Patent Publication Number: US-2021167623-A1

Title: Systems and methods for universal serial bus (usb) power delivery with multiple charging ports

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application claims the benefit and priority of and priority to U.S. National Stage application Ser. No. 17/268,935, filed on Feb. 16, 2021, which is a national stage application of International Application No. PCT/US2019/048739, filed Aug. 29, 2019, the entire disclosures of which are incorporated by reference herein. 
    
    
     BACKGROUND 
     All residential and commercial buildings have wall outlets for powering AC-powered devices, such as lights, appliances, electronic devices, computers, and mobile devices. The AC-powered devices typically have a power cord with a plug configured to be connected to and removed from the wall outlet. 
     An outlet is a female connector with slots or holes in the wall outlet. The slots are configured to receive a male connector often referred to as a plug. The plug has protruding prongs, blades, or pins that fit into matching slots in the wall outlet. The wall outlet is enclosed by a cover typically called a wall plate, face plate, outlet cover, socket cover, or wall cover. Different countries have different national standards for wall outlets. The national standards differ by voltage rating, current rating, connector shape, connector size, and connector type. 
     Due to proliferation of various rechargeable consumer electronic devices, such as cell phones, laptops, tablets, personal digital assistants (PDA&#39;s), and the like, there is a need to charge and/or connect to such devices. Most of these devices are powered by low voltage. Recharging these devices may be facilitated through the use of standard interfaces, such as a Universal Serial Bus (USB). 
     There have been developed a number of standards and solutions for providing power via USB. USB standards define the physical and electrical specifications of USB. Examples of these standards include USB 3.1, USB Power Delivery, and their revisions. USB has several types of connectors including USB Type-A and Type-C. Such USB Connectors can be used to supply power to a device. 
     SUMMARY 
     Embodiments of the present disclosure are described in detail with reference to the drawing figures wherein like reference numerals identify similar or identical elements. 
     An aspect of the present disclosure features a universal serial bus (USB) charging system configured to charge connected electronic devices. The system includes a power supply including a power supply including a plurality of power converters and a plurality of power supply outputs electrically coupled to the plurality of power converters, respectively, each of the plurality of power converters configured to convert an input voltage to a plurality of different output voltages; a plurality of charging ports electrically coupled to the plurality of power supply outputs, respectively, each of the plurality of charging ports configured to connect to, and provide an output voltage selected from the plurality of different output voltages to, an electronic device; and a controller in electrical communication with the power supply and the plurality of charging ports. The controller includes one or more processors and a memory having stored thereon instructions which, when executed by the processor, cause the controller to: communicate information regarding the plurality of different output voltages to first and second electronic devices via respective first and second charging ports of the plurality of charging ports; receive, via the respective first and second charging ports, information regarding first and second output voltages selected from the plurality of different output voltages by the respective first and second electronic devices; and control the power supply to provide the selected first output voltage to the first electronic device and to provide the selected second output voltage to the second electronic device. 
     In another aspect of the present disclosure, the USB charging system further includes a first power delivery (PD) integrated circuit and a second PD integrated circuit, the first and second PD integrated circuits in electrical communication with the controller and configured to selectively disable transmission of electrical energy to corresponding charging ports. 
     In an aspect of the present disclosure, the controller communicates a first set of output voltages to the first electronic device and communicates a second set of output voltages to the second electronic device, wherein the first set is different from the second set. 
     In another aspect of the present disclosure, the instructions, when executed by the one or more processors, further cause the controller to determine the first and second sets of output voltages based on at least one parameter associated with the first and second electronic devices, respectively. 
     In yet another aspect of the present disclosure, the at least one parameter is at least one of the current being drawn by each of the first and second electronic devices, the charge levels of each of the first and second electronic devices, the period over which each of the first and second electronic devices have been charged by the USB charging system, and the priority level of each of the first and second electronic devices. 
     In a further aspect of the present disclosure, the charging ports are USB Type-C charging ports. 
     In yet a further aspect of the present disclosure, the priority level is determined based on the order in which the first and second electronic devices are connected to the USB charging system. 
     In an aspect of the present disclosure, the system further includes a current sense resister coupled to each of the first and second charging ports. The instructions, when executed by the one or more processors, cause the controller to measure voltage across each of the current sense resistors and determine a charge level of each of the first and second electronic devices based on the measured voltages. 
     In another aspect of the present disclosure, the controller determines a first set of output voltages that includes an output voltage greater than the output voltages in the second set of output voltages, if the first electronic device has the lower charge level than the second electronic device. In yet another aspect of the present disclosure, the first and second sets of output voltages are determined based on total power that can be provided by the USB charging system. 
     Yet another aspect of the present disclosure presents a method for charging electronic devices. The method includes communicating information regarding different output voltages to first and second electronic devices via first and second charging ports, respectively, receiving, via the respective first and second charging ports, information regarding first and second output voltages selected by the respective first and second electronic devices from the different output voltages, converting an input voltage to the selected first and second output voltages, and providing the selected first output voltage to the first electronic device and providing the selected second output voltage to the second electronic device. 
     In an aspect of the present disclosure, a first set of output voltages is communicated to the first electronic device and a second set of output voltages is communicated to the second electronic device, wherein the first set is different from the second set. 
     In another aspect of the present disclosure, the method includes determining the first and second sets of output voltages based on at least one parameter associated with each of the first and second electronic devices, respectively. 
     In yet another aspect of the present disclosure, the at least one parameter is at least one of the current being drawn by each of the first and second electronic devices, the charge levels of each of the first and second electronic devices, the period over which each of the first and second electronic devices have been charged, and the priority level of each of the first and second electronic devices. 
     In a further aspect of the present disclosure, the method includes determining the priority level based on the order in which the first and second electronic devices are connected to the USB charging system. 
     In yet a further aspect of the present disclosure, the method includes measuring a first current supplied to the first electronic device, determining a first charge level based on the first current, measuring a second current supplied to the second electronic device, and determining a second charge level based on the second current. 
     In another aspect of the present disclosure, the method includes determining whether the first electronic device has a lower charge level than the second electronic device, wherein the first and second sets of output voltages are determined so that the first set of output voltages includes an output voltage greater than the output voltages in the second set of output voltages, if it is determined that the first electronic device has a lower charge level than the second electronic device. In yet another aspect of the present disclosure, the first and second sets of output voltages are determined based on total power that can be provided by the USB charging system. 
     According to an aspect of the present disclosure, a universal serial bus (USB) charging system includes a power supply including a plurality of power converters and a plurality of power supply outputs electrically coupled to the plurality of power converters, respectively. Each of the plurality of power converters is configured to convert an input voltage to a plurality of output voltages. A plurality of charging ports are electrically connected with the plurality of power supply outputs, respectively. Each of the plurality of charging ports is configured to provide an output voltage selected from the plurality of output voltages to an electronic device. A logic circuit is in electrical communication with the power supply and the plurality of charging ports. The logic circuit is configured to provide direct feedback to the power supply to output a particular output voltage of the plurality of output voltages to the plurality of charging ports. 
     According to an aspect of the present disclosure, a first power converter of the plurality of power converters simultaneously outputs a first output voltage different from a second output voltage output by a second power converter of the plurality of power converters. 
     According to an aspect of the present disclosure, each respective electronic device connected with each respective charging port of the plurality of charging ports may receive a same output voltage. 
     According to an aspect of the present disclosure, each of the plurality of charging ports may be a USB Type-C charging port. 
     According to an aspect of the present disclosure, voltages of the plurality of output voltages may range from substantially 5 volts to substantially 20 volts. 
     According to an aspect of the present disclosure, the logic circuit may include a first power delivery (PD) controller integrated circuit (IC) and a second PD controller IC. The first PD controller IC may be electrically connected with a first charging port of the plurality of charging ports. The second PD controller IC may be electrically connected with a second charging port of the plurality of charging ports. 
     According to an aspect of the present disclosure, the first PD controller IC may be in electrical communication with the second PD controller IC. 
     According to an aspect of the present disclosure, the USB charging system may include a thermistor electrically connected with at least one PD controller IC. The thermistor may be configured to reduce power delivery to the at least one charging port of the plurality of charging ports in response to a temperature exceeding a first predetermined threshold. The reduced power delivery to the at least one charging port of the plurality of charging ports may be maintained at an above-zero level until a temperature of the charging port is reduced below a second predetermined threshold. 
     According to an aspect of the present disclosure, each of the plurality of power converters may be an AC to DC power converter or a DC to DC power converter. 
     According to an aspect of the present disclosure, a method for charging a plurality of electronic devices using a USB charging system includes providing AC power from a power source to an AC/DC converter. The method includes receiving, at the AC/DC converter, the AC power from the power source. The AC/DC converter includes a plurality of power converters and a plurality of power supply outputs electrically coupled to the plurality of power converters, respectively. Each of the plurality of power converters is configured to convert the AC power to a plurality of different DC output voltages. The method includes receiving, at the AC/DC converter, direct feedback from a logic circuit in direct electrical communication with the AC/DC converter, and outputting a particular DC output voltage from the AC/DC converter in response to the direct feedback received. The logic circuit is in electrical communication with a plurality of charging ports. The method includes delivering the particular DC output voltage to each of the plurality of electronic devices respectively connected with each of the plurality of charging ports. 
     According to an aspect of the present disclosure, a first power converter of the plurality of power converters simultaneously outputs a first output voltage different from a second output voltage output by a second power converter of the plurality of power converters. 
     According to an aspect of the present disclosure, each respective electronic device connected with each respective charging port of the plurality of charging ports may receive a same output voltage. 
     According to an aspect of the present disclosure, each of the plurality of charging ports may be a USB Type-C charging port. 
     According to an aspect of the present disclosure, the plurality of output voltages may range from substantially 5 volts to substantially 20 volts. 
     According to an aspect of the present disclosure, the logic circuit may include a first power delivery (PD) controller integrated circuit (IC) and a second PD controller IC, the first PD controller IC electrically connected with a first charging port of the plurality of charging ports and the second PD controller IC electrically connected with a second charging port of the plurality of charging ports. The first PD controller IC may be electrically connected with the second PD controller IC. 
     According to an aspect of the present disclosure, a thermistor may be electrically connected with at least one PD controller IC. The thermistor may be configured to reduce power delivery to the at least one charging port of the plurality of charging ports in response to a temperature exceeding a first predetermined threshold. The reduced power delivery to the at least one charging port of the plurality of charging ports is maintained at an above-zero level until a temperature of the charging port is reduced below a second predetermined threshold. 
     According to an aspect of the present disclosure, a firmware-upgradable USB receptacle includes a USB receptacle having a logic circuit including at least one power delivery (PD) controller integrated circuit (IC). The logic circuit has a first memory storing firmware configured to control the logic circuit. At least one USB charging port is in communication with the logic circuit. The firmware stored on the first memory of the logic circuit is modified by communicably coupling a device to the at least one USB charging port. The device has a processor and a second memory storing computer instructions configured to modify the firmware stored on the first memory of the logic circuit. The firmware stored on the first memory of the logic circuit is modified by transmitting computer instructions from the device to the logic circuit. 
     According to an aspect of the present disclosure, the device may be a Smartphone, a USB drive, a Tablet, or a computer. The Smartphone, USB drive, tablet or computer may have a firmware update application thereon. The firmware update application is configured to modify the firmware stored on the first memory of the logic circuit. 
     According to an aspect of the present disclosure, the at least one USB charging port may be a USB Type-C charging port. 
     According to an aspect of the present disclosure, the device may be communicably coupled to the at least one USB charging port through a USB cable. The USB cable may be a USB Type-C cable. 
     According to an aspect of the present disclosure, a system for wirelessly modifying firmware includes a USB receptacle having a logic circuit including at least one power delivery (PD) controller integrated circuit (IC). The logic circuit has a first memory storing firmware configured to control the logic circuit. The logic circuit has a first wireless antenna. The firmware stored on the first memory of the logic circuit is modified by communicably coupling a device to the logic circuit through a wireless connection. The device has a second wireless antenna configured to communicate with the first wireless antenna of the logic circuit. The device has a processor and a second memory storing computer instructions configured to modify the firmware stored on the first memory of the logic circuit. The firmware stored on the first memory of the logic circuit is modified by wirelessly transmitting computer instructions from the device to the logic circuit. 
     According to an aspect of the present disclosure, the first wireless antenna of the logic circuit may communicate with the second wireless antenna of the device through a Bluetooth or WiFi signal. 
     According to an aspect of the present disclosure, the device may be a Smartphone, a USB drive, a Tablet, or a computer. The device may have a firmware update application thereon. The firmware update application is configured to modify the firmware stored on the first memory of the logic circuit. 
     According to an aspect of the present disclosure, a USB charging system includes an AC-DC power supply configured to output a plurality of output voltages. A USB Type-A charging port is in electrical communication with the AC-DC power supply. The USB Type-A charging port is configured to provide a first output voltage to a first electronic device. A USB Type-C charging port is in electrical communication with the AC-DC power supply. The USB Type-C charging port is configured to provide a second output voltage to a second electronic device. The first and second output voltages differ from each other. A voltage regulator is in electrical communication with the AC-DC power supply and the USB Type-A charging port. The voltage regulator is configured to maintain the first output voltage provided by the USB Type-A charging port. A switch is in electrical communication with the AC-DC power supply and the USB Type-A charging port. The switch is configured to bypass the voltage regulator. A logic circuit is in electrical communication with the voltage regulator and the switch. The logic circuit is configured to enable or disable the voltage regulator by opening or closing the switch. 
     According to an aspect of the present disclosure, each respective electronic device connected with each respective charging port may receive a different output voltage. 
     According to an aspect of the present disclosure, the first output voltage may be a fixed output voltage, and the second output voltage may be a variable output voltage. 
     According to an aspect of the present disclosure, voltages of the plurality of output voltages may range from substantially 5 volts to substantially 20 volts. 
     According to an aspect of the present disclosure, the voltage regulator may be a linear voltage regulator or a DC-DC converter. 
     According to an aspect of the present disclosure, a USB charging system includes an AC-DC power supply configured to output a plurality of output voltages. A first USB Type-C charging port is in electrical communication with the AC-DC power supply. The first USB Type-C charging port is configured to provide a first output voltage to a first electronic device. A second USB Type-C charging port is in electrical communication with the AC-DC power supply. The second USB Type-C charging port is configured to provide a second output voltage to a second electronic device. The first and second output voltages differ from one another. A voltage regulator is in electrical communication with the AC-DC power supply and the first or second USB Type-C charging ports. The voltage regulator is configured to regulate the first or second output voltages of the first or second USB Type-C charging ports. A first switch is in electrical communication with the AC-DC power supply and the first USB Type-C charging port. The first switch is configured to bypass the voltage regulator. A second switch is electrically connected with the AC-DC power supply and the second USB Type-C charging port. The second switch is configured to bypass the voltage regulator. A logic circuit is in electrical communication with the voltage regulator and the first and second switches. The logic circuit is configured to enable or disable the voltage regulator by opening or closing the first or second switches. 
     According to an aspect of the present disclosure, a third switch may be in electrical communication with the AC-DC power supply and the first USB Type-C charging port. The third switch may be configured to activate the voltage regulator. A fourth switch may be in electrical communication with the AC-DC power supply and the second USB Type-C charging port. The fourth switch may be configured to activate the voltage regulator. 
     According to an aspect of the present disclosure, each of the first, second, third and fourth switches may be configured to be individually enabled or disabled by the logic circuit. 
     According to an aspect of the present disclosure, each respective electronic device connected with each respective charging port may receive a different output voltage. 
     According to an aspect of the present disclosure, each respective electronic device connected with each respective charging port may receive a different output voltage. 
     According to an aspect of the present disclosure, voltages of the plurality of output voltages may range from substantially 5 volts to substantially 20 volts. 
     According to an aspect of the present disclosure, the voltage regulator may be a linear voltage regulator or a DC-DC converter. 
     According to an aspect of the present disclosure, the logic circuit is configured to regulate a wattage delivered to two or more charging ports of the plurality of charging ports. The logic circuit is configured to detect a temperature of two or more charging ports of the plurality of charging ports. The logic circuit is configured to reduce a wattage delivered to a particular charging port of the plurality of charging ports if a temperature detected in the particular charging port of the plurality of charging ports exceeds a predetermined threshold. 
     According to an aspect of the present disclosure, a maximum wattage deliverable to each charging port of the plurality of charging ports is from about 1 watt to about 100 watts. 
     According to an aspect of the present disclosure, the plurality of charging ports includes a USB Type-A port, a USB Type-C port, or a Line-Voltage port. 
     According to an aspect of the present disclosure, a thermistor is configured to collect temperature data for the USB charging system and communicate the temperature data to the logic circuit. 
     According to an aspect of the present disclosure, the logic circuit is configured to detect a current drawn by two or more charging ports of the plurality of charging ports (e.g., a current drawn by line voltage ports). The logic circuit is configured to reduce a current drawn by a particular charging port of the plurality of charging ports if a temperature detected in the particular charging port of the plurality of charging ports exceeds a predetermined threshold. and/or if a current drawn by a particular line voltage port exceeds a predetermined threshold 
     According to an aspect of the present disclosure, a thermally conductive housing is in thermal contact with the power supply, the plurality of charging ports and the logic circuit. The thermally conductive housing is configured to transfer heat away from at least one of the power supply, the charging ports of the plurality of charging ports, or the logic circuit to reduce a temperature of the USB charging system. 
     According to an aspect of the present disclosure, the thermally conductive housing includes a metal, such as Aluminum. 
     According to an aspect of the present disclosure, the logic circuit is configured to monitor a state of charge of a device connected with each charging port of the plurality of charging ports. The logic circuit is configured to regulate a wattage delivered to the device connected with each charging port of the plurality of charging ports. The logic circuit is configured to reduce a wattage delivered to a first charging port of the plurality of charging ports when a state of charge of a first device connected with the first charging port of the plurality of charging ports exceeds a predetermined threshold. The logic circuit is configured to increase a wattage delivered to a second device connected with a second charging port of the plurality of charging ports when the state of the charge of the first device exceeds the predetermined threshold. 
     According to an aspect of the present disclosure, a maximum combined wattage deliverable to the first and second charging ports may be about 60 watts. The maximum combined wattage deliverable to the first and second charging ports may also be above or below 60 watts. 
     According to an aspect of the present disclosure, the reduced wattage delivered to the first device connected with the first charging port of the plurality of charging ports is maintained at an above-zero level, by the logic circuit, when the state of charge of the first device is below a maximum state of charge for the first device. 
     According to an aspect of the present disclosure, the reduced wattage delivered to the first device connected with the first charging port of the plurality of charging ports is maintained at 0 watts, by the logic circuit, when the state of charge of the first device reaches a maximum state of charge for the first device. 
     According to an aspect of the present disclosure, when the state of charge of the first device reaches the maximum state of charge for the first device, the increased wattage delivered to the second device is maintained at up to about 60 watts by the logic circuit. The increased wattage may also be above or below 60 watts. 
     According to an aspect of the present disclosure, a first current sensor is connected with the first charging port. A second current sensor is connected with the second charging port. The first current sensor communicates data of a first load current in the first current sensor to the logic circuit. The second current sensor communicates data of a second load current in the second current sensor to the logic circuit. 
     According to an aspect of the present disclosure, the logic circuit is configured to receive the data of the first load current and the second load current, and adjust the wattage delivered to the device connected with each charging port of the plurality of charging ports in real-time. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       One or more aspects of the present invention are particularly pointed out and distinctly claimed as examples in the claims at the conclusion of the specification. The foregoing and other objects, features, and advantages of the present invention may be more readily understood by one skilled in the art with reference being had to the following detailed description of several embodiments thereof, taken in conjunction with the accompanying drawings wherein like elements are designated by identical reference numerals throughout the several views, and in which: 
         FIG. 1  depicts a block diagram of a USB power delivery system architecture in accordance with an exemplary embodiment of the disclosure; 
         FIG. 2  depicts a schematic diagram of an example embodiment of the AC/DC converter of  FIG. 1 ; 
         FIG. 3  depicts a schematic diagram of an example embodiment of a pair of DC/DC buck converters of  FIG. 1 ; 
         FIG. 4  depicts a schematic diagram of an example embodiment of a pair of switching elements of  FIG. 1 ; 
         FIG. 5A  depicts a schematic diagram of an example embodiment of a pair of USB power delivery controller integrated circuits of  FIG. 1 ; 
         FIG. 5B  depicts a schematic diagram of an example embodiment of a pair of USB power delivery controller integrated circuits of  FIG. 1 ; 
         FIG. 6  depicts a schematic diagram of an example embodiment of a master controller of  FIG. 1 ; 
         FIG. 7  depicts a schematic diagram of an example embodiment of USB Type-C power distribution connectors of  FIG. 1 ; 
         FIG. 8  is a flow chart illustrative of the method of delivering power in accordance with the present disclosure; 
         FIG. 9  is a flow chart illustrative of the method of charging electronic devices in accordance with the present disclosure; 
         FIG. 10  depicts an example graph of battery percentage over time for two electronic devices, in accordance with the present disclosure; 
         FIG. 11  depicts an example graph of power delivered to two electronic devices over time, in accordance with the present disclosure; 
         FIG. 12  is a flow chart illustrative of the method of charging electronic devices in accordance with the present disclosure; 
         FIG. 13  depicts a block diagram of a USB power delivery system architecture including a direct feedback system in accordance with an exemplary embodiment of the disclosure; 
         FIG. 14  depicts a schematic diagram of an example embodiment of switching elements of  FIG. 13 ; 
         FIG. 15  depicts a schematic diagram of an example embodiment of a pair of USB power delivery (PD) controller integrated circuits (IC) of  FIG. 13 ; 
         FIG. 16  depicts a schematic diagram of an example embodiment of the AC/DC converter of  FIG. 13 ; 
         FIG. 17  depicts a block diagram of a USB power delivery system architecture including a direct feedback system and thermistors in accordance with an exemplary embodiment of the disclosure; 
         FIG. 18  depicts exemplary mechanical and electrical connections between a power board and a logic board in accordance with an exemplary embodiment of the disclosure; 
         FIG. 19  is a cross-sectional view along lines  18   a - 18   b  of a mechanical connection between a power board and a logic board in accordance with an exemplary embodiment of the disclosure; 
         FIGS. 20A and 20B  each depict an exemplary system for upgrading firmware of a USB receptacle in accordance with an exemplary embodiment of the disclosure; 
         FIG. 21  depicts an exemplary system for wirelessly upgrading firmware of a USB receptacle in accordance with an exemplary embodiment of the disclosure; 
         FIG. 22  is a block diagram of a USB Type-A charging port, a USB Type-C charging port, a single AC-DC power supply and a single voltage regulator in accordance with an exemplary embodiment of the disclosure; 
         FIG. 23  is a flowchart of an exemplary algorithm employed by a logic circuit of the USB charging systems of  FIGS. 22 and 24 ; 
         FIG. 24  is a block diagram of two USB Type-C charging ports and a single voltage regulator in accordance with an exemplary embodiment of the disclosure; 
         FIG. 25  depicts a block diagram of a USB power delivery system architecture including a logic circuit configured to regulate a temperature of a plurality of charging ports in accordance with an exemplary embodiment of the disclosure; 
         FIG. 26  depicts a block diagram of a USB power delivery system architecture including a logic circuit configured to detect a flow of current and regulate a temperature of a plurality of charging ports in accordance with an exemplary embodiment of the disclosure; 
         FIG. 27  depicts a block diagram of a USB power delivery system architecture including a logic circuit configured to regulate a temperature of a plurality of charging ports, and a thermally conductive housing in accordance with an exemplary embodiment of the disclosure; 
         FIG. 28  depicts a block diagram of a USB power delivery system architecture including a logic circuit configured to detect a flow of current and regulate a temperature of a plurality of charging ports, and a thermally conductive housing in accordance with an exemplary embodiment of the disclosure. 
         FIG. 29  depicts a block diagram of a USB power delivery system architecture including a logic circuit configured to regulate wattages delivered to electronic devices connected with each of a plurality of charging ports in accordance with an exemplary embodiment of the disclosure; 
         FIG. 30  depicts exemplary hysteresis bands in accordance with aspects of the present disclosure; and 
         FIGS. 31A, 31B, 31C, 31D and 31E  depict an exemplary algorithm employable by a USB power receptacle for dynamic load sharing. 
     
    
    
     The figures depict embodiments of the present disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the present disclosure described herein. 
     DETAILED DESCRIPTION 
     The present disclosure is directed to systems and methods for implementing USB power delivery mechanisms with multiple charging ports. Embodiments of the present disclosure are described herein below with reference to the accompanying drawings. However, it is to be understood that the disclosed embodiments are merely exemplary of the disclosure and may be embodied in various forms. Well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure. 
     For the purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to the exemplary embodiments illustrated in the drawings, and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the present disclosure is thereby intended. Any alterations and further modifications of the inventive features illustrated herein, and any additional applications of the principles of the present disclosure as illustrated herein, which would occur to one skilled in the relevant art and having possession of this disclosure, are to be considered within the scope of the present disclosure. 
     “About” or “approximately” or “substantially” as used herein may be inclusive of the stated value and means within an acceptable range of variation for the particular value as determined by one of ordinary skill in the art, considering the measurement in question and the error associated with measurement of the particular quantity (e.g., the limitations of the measurement system). For example, “about” or “substantially” may mean within one or more standard variations, or within ±30%, 20%, 10%, 5% of the stated value. 
     Descriptions of technical features or aspects of an exemplary embodiment of the present disclosure should typically be considered as available and applicable to other similar features or aspects in another exemplary embodiment of the present disclosure. Accordingly, technical features described herein according to one exemplary embodiment of the present disclosure may be applicable to other exemplary embodiments of the present disclosure, and thus duplicative descriptions may be omitted herein. 
     Exemplary embodiments of the present disclosure will be described more fully below (e.g., with reference to the accompanying drawings). Like reference numerals may refer to like elements throughout the specification and drawings. 
     Line voltage refers to a voltage, typically Alternating Current (AC), that is supplied to buildings/residences (e.g., electric light and power), for example, 110 V AC, 115 V AC, 120 V AC, 125 V AC, 208 V AC, 220 V AC, 230 V AC, 240 V AC, single or multiphase. Line voltage is typically made available to the end user standard plug/outlet configurations standardized by the National Electrical Manufacturers&#39; Association (NEMA) configurations. One such standardized configuration is a NEMA 5-15 configuration which denotes a nominal 125 V AC/15 Amp outlet. 
     Low voltage refers to a voltage which is less than a certain threshold (50 Volts for example, AC or DC). This reduced voltage is typically used for communication, signaling, data/multimedia transmission, low voltage charging, and the like. For the purposes of this application, the term low voltage also includes optical transmission (although no electrical voltage is actually transmitted by optical transmission). 
     Low voltage ports denote any suitable type of low voltage ports, such as, but not limited, to Universal Serial Bus (USB), Audio/Video/Multimedia ports, Digital Visual Interface (DVI), Ethernet/data ports, High Definition Multimedia Interface (HDMI), IEEE 1394 (FireWire), Separate Video (S-Video), Video Graphics Array (VGA), Telephone, and the like, or any suitable combination thereof. For the purposes of this application, low voltage ports can also include fiber optic ports (although no electrical voltage is actually transmitted by fiber optic ports). USB ports can further be broken out into various form factors such as Type A, Type B, Type C, Mini-A, Mini-B, Micro-A, Micro-B, or any other suitable form. 
     The USB power delivery systems and methods of the present disclosure can provide power delivery charging capabilities to multiple ports. The total power is shared when multiple devices are connected. It is contemplated that the USB power delivery systems and methods of the present disclosure can have single or multiple ports by simply adding DC/DC sections and control logic. Most existing USB Type-C chargers are single port or dual port with no power distribution functionality. The USB Type-C power delivery systems and methods of the present disclosure can provide full or partial power delivery voltages depending on the status of the devices connected to the USB power delivery systems. 
       FIG. 1  depicts a USB power delivery system architecture  100  in accordance with the present disclosure. In an embodiment, the alternating current (AC) power source  110  supplies AC power to an AC/DC converter  200 . It is contemplated that the AC power source  110  can be any AC power source such as from a residential or commercial electrical system, from a solar power supply&#39;s inverter, an AC generator, or any other suitable power supply source. The AC/DC converter  200  converts the AC voltage supplied by the power supply, for example 120 V AC, to a lower level DC voltage, for example, 17 V DC. 
     Next, the DC voltage generated at the AC/DC converter  200  is processed by a DC/DC converter block  300 . The DC/DC converter block  300  may step down the DC voltage. The DC/DC converter block  300  may include, for example, a number of buck converters  302   a ,  302   b  as well as voltage control logic  306 . It is contemplated that other types of DC/DC converters may be used such as, for example, linear regulators. 
     In an aspect of the present disclosure, the outputs  304   a ,  304   b  of the DC/DC converter block  300  supply power to a logic circuit  400  that includes switching elements  404   a ,  404   b , USB power distribution (PD) integrated circuits (IC)  402   a ,  402   b , and a master controller IC  406 . The master controller IC  406  decides how much power to supply through the USB power delivery controller ICs  402   a ,  402   b , to either of the two USB Type-C power distribution connectors  190   a ,  190   b.    
     The USB power delivery system  100  advertises or publishes available voltage levels to devices connected to the connectors  190   a ,  190   b , which, in turn, reply with requested voltage levels. The available voltage levels may be determined based on the charge levels of one or more devices connected to either or both of the USB Type-C power distribution connectors  190   a ,  190   b  and the output power capacity of the USB power delivery system  100 . The USB power delivery system  100  then outputs voltages to either or both of the USB Type-C power distribution connectors  190   a ,  190   b  based on the voltage levels requested by the connected one or more devices. 
     The first USB power delivery controller IC  402   a , and the second USB power delivery controller IC  402   b , are electrically coupled to the master controller IC  406  and configured to selectively disable transmission of electrical energy to corresponding connectors  190   a ,  190   b . This includes disabling transmission of electrical energy to a connector  190   a ,  190   b  when a corresponding electronic device connected to a connector  190   a ,  190   b  is fully charged or when an overcurrent condition is detected. 
     The master controller IC  406  communicates with the voltage control logic  306  to control the DC/DC buck boost converters  302   a ,  302   b . Ultimately, the two or more USB Type-C connectors  190   s ,  190   b  are supplied power from the logic circuit  400  for supplying power to devices connected to these USB Type-C connectors  190   s ,  190   b . It is contemplated that devices can be electric and/or electronic. In an embodiment, mechanical terminals  170  and receptacles  180   a ,  180   b  may operate off of the same power supply  110 . It is contemplated that these receptacles  180   a ,  180   b  may be used to supply AC power to a variety of items, for example, lights, TVs, radio, etc. 
       FIG. 2  depicts a schematic of an AC/DC converter  200  in accordance with the present disclosure. The AC/DC converter  200  typically takes an input from an AC power source  110  and processes it through the bridge rectifier  202 . Bridge rectifier  202  converts AC to DC voltage by providing full wave rectification from a two-wire AC input. The polarity of the output is the same regardless of the polarity of the input. The DC signal created by the bridge rectifier  202  may have some amount of ripple on it, which is filtered out by filtering capacitors and inductors coupled to the output terminals of the bridge rectifier  202 . The DC voltage is then stepped down with a transformer  204  and further filtered by a filter  206 . A flyback converter  208  may be used to regulate the DC voltage. 
       FIG. 3  depicts a schematic of a pair of DC/DC buck-boost converters  302   a ,  302   b , in accordance with the present disclosure. The regulated voltage produced by the AC/DC converter  200  is further processed by a pair of buck-boost converters. A DC/DC buck-boost converter  302   a ,  302   b  is a type of DC/DC converter that can have an output voltage magnitude that is either greater than or less than the input voltage magnitude. Typically, DC/DC buck-boost converters  302   a ,  302   b  utilize an internal PWM controller to support a wide range of output voltages, for example, 3.3 V to 65 V. 
       FIGS. 4, 5A, and 5B  depict a schematic of a pair of switching elements  404   a ,  404   b , and a pair of USB power delivery controller ICs  402   a ,  402   b , in accordance with the present disclosure. The voltage VBUS (for example, 5, 9, or 15 V DC) from the DC/DC buck-boost converters  302   a ,  302   b  is provided to the switching element  404   a ,  404   b , which are controlled by the USB power delivery controller ICs  402   a ,  402   b  by outputting a gate control current. The USB power delivery controller ICs  402   a ,  402   b , may include a current sense amplifier, a high voltage regulator, overvoltage protection, overcurrent protection, and supply switch blocks. The USB power delivery controller ICs  402   a ,  402   b  also may provide Electro-static discharge (ESD) protection to the USB Type-C power distribution connectors  190   a ,  190   b.    
     The USB power delivery controller ICs  402   a ,  402   b  can operate in accordance with BC 1.2, Apple®, Qualcomm&#39;s® quick charge 4.0, and Samsung® AFC. In one embodiment, the USB power delivery controller ICs  402   a ,  402   b , can supply full power delivery charging capability to multiple ports. When multiple devices are connected to the USB power delivery system  100 , the total power that can be output from the USB power delivery system  100  can be shared between those devices. Thus, full or partial power delivery voltages can be provided to the devices. It is contemplated that there are multiple USB Type-C power distribution connectors  190   a ,  190   b , that can share power delivery according to an appropriate ratio (e.g., based on a charge level of the devices connected to the connectors  190   a ,  190   b ) or supply one of the connectors  190   a ,  190   b  full power delivery. It is contemplated that other types of connectors, including other types of USB connectors may be used. 
       FIG. 6  depicts a schematic of a master controller IC  406  in accordance with the present disclosure. The master controller IC  406  determines the charging voltage levels that can be supplied to one or more electronic devices connected to one or more of the connectors  190   a ,  190   b  without exceeding the output power capacity of the USB power delivery system, and transmits the charging voltage levels to the one or more electronic devices. When the master controller IC  406  receives the charging voltage levels selected by the one or more electronic devices, the master controller IC  406  communicates with the voltage control logic  306  of  FIG. 1  to cause the voltage control logic  306  to adjust the output voltages of the pair of DC/DC buck boost converters  302   a ,  302   b  based on the charging voltage levels selected by the one or more electronic devices. 
     In one embodiment, the master controller IC  406  can re-determine the voltage levels for charging the first device and/or the second device based on further communications with the first device and/or the second device; and output a first voltage at an updated first voltage level and/or a second voltage at an updated second voltage level. In another embodiment, the master controller IC  406  communicates to the first and/or second devices the charging voltage levels available through its respective low voltage port connections. The device charging voltage for each device is determined by the master controller IC  406  as a function of an available charging power and the voltage level for charging the first device and/or the second device. The USB power delivery controller ICs  402   a ,  402   b  handle all USB C protocols and performs functions such as overcurrent protection. 
     In one embodiment, the master controller IC  406  can cause the USB power delivery system  100  to determine a priority of the first and second devices including determining which of the first device or the second device is first connected to a charging system. In another embodiment, the master controller IC  406  causes the USB power delivery system  100  to determine the priority of the first and second devices including measuring, estimating, or deducing the charge level of the first device and the second device. The charging according to the priority includes charging the device having the lower charge level with a higher voltage level than the device having the higher charge level. As used herein, charge level refers to the level at which a rechargeable battery is charged relative to full charge. It may also be referred to as state of charge. 
     In one embodiment, a first device, when connected to the first USB Type-C power distribution connector  190   a , may request two thirds of the power capacity of the USB power delivery system  100 , and a second device, when connected to the second USB Type-C connector  190   b , may also request two thirds of the power capacity of the USB power delivery system  100 . The master controller IC  406  may determine that the first device has priority and deliver the two thirds of the available power to the first device, and only one third of the available power to the second device. 
     In another embodiment, a first device, when connected to the first USB Type-C power distribution connector  190   a , may request two thirds of the available power, and a second device, when connected to the second USB Type-C connector  190   b , may also request two thirds of the available power. The master controller IC  406  may determine that both devices should share power equally and deliver half of the available power to the first device and the other half of the available power to the second device. It is contemplated that any division of power between the two USB Type-C power distribution connectors  190   a ,  190   b  may be determined by the master controller IC  406 . 
       FIG. 7  depicts a schematic of USB Type-C power distribution connectors  190   a ,  190   b  in accordance with the present disclosure. The USB Type-C power distribution connectors  190   a ,  190   b  connect with both the USB power delivery system  100  and external devices. In an embodiment, the USB Type-C power distribution connectors  190   a ,  190   b  conform to a standard configuration, for example, a double-sided connector with 24 pins. The female connector may include four power pins and four ground pins, two differential pairs for high-speed USB data, four shielded differential pairs for Enhanced SuperSpeed data, two Sideband Use (SBU) pins, and two Configuration Channel (CC) pins. The CC pins on the device are used to carry USB power distribution communications. 
       FIG. 8  is a flow chart illustrative of a method of delivering power  800  in accordance with the present disclosure. The method  800  includes various blocks described in an ordered sequence. However, those skilled in the art will appreciate that one or more blocks of the method  800  may be performed in a different order, repeated, and/or omitted without departing from the scope of the present disclosure. Further, the below description of the method  800  refers to various actions or tasks performed by the master controller IC  406 , but those skilled in the art will appreciate that in some instances, the master controller IC  406  performs the actions or tasks via one or more software applications, such as the application which could be firmware, executing on the master controller IC  406 . 
     The method may begin with the master controller IC  406  communicating or publishing different voltage levels to first and second electronic devices via respective first and second connectors  190   a ,  190   b  (block  810 ). For example, a USB Type-C device, such as a mobile device or a laptop, may be connected to the first USB Type-C power distribution connector  190   a . Then, the master controller IC  406  receives first and second voltage levels from the respective first and second electronic devices via the respective first and second charging connectors (block  820 ). The communication of the voltage levels may be conducted through the Configuration Channel (CC) pins of the USB connectors  190   a ,  190   b . The second device may be different from the first device, with different power or charging requirements. For example, the first device could require 2 watts and the second device could require 7 watts. 
     The master controller IC  406  then causes an input voltage to be converted to the first and second output voltages having the selected first and second voltage values, respectively (block  830 ). For example, the first electronic device may select +15 V DC, whereas the second electronic device may select +5 V DC. Thus, the input voltage, which may be 120 V AC, gets converted via the pair of DC/DC buck-boost converters  302   a ,  302   b  to +15 V DC and +5 V DC, respectively. 
     Finally, the master controller IC  406  controls the power supply (comprised of the USB power delivery controller ICs  402   a ,  402   b  and the DC/DC converter block  300 ) to output a first voltage at the received first voltage level to the first electronic device and output the second voltage at the received second voltage level to the second electronic device (block  840 ). For example, the master controller IC  406  may determine that the first electronic device has requested +5 V DC, and communicate that information to both the USB power delivery controller IC  402   a  and the DC/DC converter block  300 , which may adjust its output according to this request. The master controller IC  406  may also determine that the second electronic device requested +15 V DC. That information is communicated to the USB power delivery controller IC  402   b  and the DC/DC converter block  300 , which may adjust its output according to this request. 
     It is contemplated that the master controller IC  406  could determine the priority levels of the devices, and set the maximum power to be supplied to the devices and the corresponding sets of voltage levels to be published to the devices, accordingly. This priority can be set, for example, by determining which device was connected first, by determining which one was closer to being fully charged (e.g., by deducing the charge level), or by a communication via USB communications. It is contemplated that additional charging ports can be utilized by adding additional logic and DC sections. 
     In another embodiment, the USB power delivery system  100  can deduce the charge level of the connected electronic devices by measuring the charge time and/or the current being provided to the connected electronic devices and analyzing the measurements in view of charging profiles provided by the connected electronic devices. Based on the deduction, the USB power delivery system  100  can reprioritize the charging of the electronic devices. In another embodiment, reprioritizing may be based on how long a single electronic device has been plugged into a USB Type-C power distribution connector  190   a ,  190   b . For example, if an electronic device has been plugged in for a substantial period, the electronic device is likely to be substantially charged and all or a large portion of output charging power may be reallocated to a more recently plugged in electronic device. 
       FIG. 9  is a flow chart illustrative of a method of charging electronic devices  900  in accordance with the present disclosure. The method may begin with the USB power delivery system  100  publishing available voltages (e.g., 5V, 9V, and 15V) to two devices connected to the connectors  190   a ,  190   b  (block  910 ). Next, the USB power delivery system  100  determines the battery charge level of the two devices based on the current draw (block  920 ). Optionally, the USB power delivery system  100  may also determine the charge level based on the amount of time the device has been charging (block  930 ). For example, a timer starts when a device is plugged into a first connector  190   a . Then another timer starts when a device is plugged into the second charging port  190   b . The USB power delivery system  100  can then determine which device has the higher battery charge level based on charging profiles of the devices (e.g., the charging profiles illustrated in  FIG. 10  and/or  FIG. 11 ) and the timers. 
     Next, depending on which device has a higher battery charge level (block  940 ), the USB power delivery system  100  prioritizes which device receives more power. If the second device is determined at block  940  to have a higher battery charge level, then the USB power delivery system  100  directs more power to the first device than to the second device by changing the voltage values that are published to each device (block  950 ). If the first device is determined at block  940  to have a higher battery charge level, then the USB power delivery system  100  directs more power to the second device than to the first device by changing the voltage values that are published to each device (block  960 ). 
       FIG. 12  is a flow chart illustrating an exemplary embodiment of a method of charging devices in accordance with the present disclosure. The method may begin with a first device being plugged into the first USB Type-C power distribution connector  190   a  of the USB power delivery system  100 . In an embodiment, the current supplied to the first device is measured using a current sense resistor (block  1202 ). Next, the master controller IC  406  determines whether a second device is plugged in during the charging of the first device (block  1204 ). If no second device is plugged in during the charging of the first device, then the USB power delivery system  100  allocates or continues to allocate the maximum amount of power to the first device by publishing all available voltage levels to the first device (block  1206 ). 
     If a second device is plugged in during the charging of the first device, then the USB power delivery system  100  measures the current supplied to the first device again and measures the current supplied to the second device (block  1208 ). 
     Next, the USB power delivery system  100  determines whether there is a significant difference between the two current measurements for the first device (block  1210 ). The significant difference may be a threshold difference indicating that the charging of the first device has transitioned from stage A to stage B of the charging cycle. If there is no significant difference between the current measurements for the first device (indicating that the charging of the first device has not transitioned from stage A to stage B of the charging cycle), the USB power delivery system  100  supplies at least equal power allocation to the first electronic device and the second electronic device (block  1212 ). Charging power is allocated equally to the first and second devices by publishing the same sets of available voltage values to the first and second devices. The published sets of available voltage values may include a maximum voltage value that, if supplied to both the first and second devices, would be within the charging capacity of the USB power delivery system  100 . 
     If there is a significant difference between the current measurements for the first device, the USB power delivery system  100  determines that the first device has entered stage B (trickle charging) as depicted in  FIG. 11  and allocates more power to the second device than to the first device (block  1214 ). This may be accomplished by publishing higher voltage voltages to the second device than to the first device. 
     In embodiments where the USB power delivery system  100  is configured to supply a constant current to the first and second electronic devices, different charging powers may be allocated between first and second electronic devices by publishing different sets of voltage values to the first and second electronic devices corresponding to those different charging powers. 
       FIG. 13  depicts a block diagram of a USB power delivery system architecture including a direct feedback system in accordance with an exemplary embodiment of the disclosure.  FIG. 14  depicts a schematic diagram of an example embodiment of switching elements of  FIG. 13 .  FIG. 15  depicts a schematic diagram of an example embodiment of a pair of USB power delivery (PD) controller integrated circuits (IC) of  FIG. 13 .  FIG. 16  depicts a schematic diagram of an example embodiment of the AC/DC converter of  FIG. 13 . 
     Referring to  FIGS. 13-16 , according to an aspect of the present disclosure, a universal serial bus (USB) charging system  1300  includes a power supply  110  including a plurality of power converters (e.g., AC/DC power converters  200 ) and a plurality of power supply outputs electrically coupled to the plurality of power converters, respectively. Each of the plurality of power converters is configured to convert an input voltage (e.g., 20 VAC) to a plurality of output voltages (e.g., 5, 9 or 15 VDC). A plurality of charging ports (e.g., USB port  190   a  and/or USB port  190   b ) are electrically connected with the plurality of power supply outputs, respectively. Each of the plurality of charging ports is configured to provide an output voltage selected from the plurality of output voltages to an electronic device. A logic circuit  400  is in electrical communication with the power supply and the plurality of charging ports. The logic circuit  400  is configured to provide direct feedback to the power supply to output a particular output voltage of the plurality of output voltages to the plurality of charging ports. Thus, the DC/DC converter block  300  described in more detail above may be omitted. Additionally, as described in more detail below, the master IC  406  may be omitted. Accordingly, a size, weight and manufacturing cost of the USB charging system  1300  may be reduced, while still maintaining a desired output power at the charging ports. 
     As an example, the electronic device receiving the output voltage may be a Smartphone, computer, Tablet or any other electronic device. The output voltage may be used to charge a battery of the electronic device. 
     According to an aspect of the present disclosure, each respective electronic device connected with each respective charging port of the plurality of charging ports may receive a same output voltage. For example, a single desired output voltage may be output to the logic circuit  400  and each of a plurality of devices respectively connected with a plurality of charging ports may receive a same output power. 
     According to an aspect of the present disclosure, each of the plurality of charging ports may be a USB Type-C charging port. According to an aspect of the present disclosure, voltages of the plurality of output voltages may range from about 5 volts to about 20 volts. However, exemplary embodiments of the present disclosure are not limited thereto, and other desired voltages may be output to the charging ports. As an example, logic circuit  400  may provide direct feedback to the power supply to output one of 5, 9 or 15 volts of direct current. 
     According to an aspect of the present disclosure, each of the plurality of power converters may be an AC to DC power converter. Each of the plurality of output voltages may be a DC output voltage. 
     An exemplary DC voltage to watts calculation formula is provided below, whish Power P is in watts (W), Voltage V is in volts (V) and current I is in amps (A): 
     
       
      
       P 
       (W) 
       =V 
       (V) 
       ×I 
       (A)  
      
     
     As an example, an output voltage of 5 Volts (direct current DC) at a current of 6 Amps provides 30 Watts according to the above-noted formula. 
     According to an aspect of the present disclosure, the logic circuit may include a first power delivery (PD) controller integrated circuit (IC)  402   a  and a second PD controller IC  402   b . The first PD controller IC  402   a  may be electrically connected with a first charging port  190   a  of the plurality of charging ports. The second PD controller IC  402   b  may be electrically connected with a second charging port  190   b  of the plurality of charging ports. 
     According to an aspect of the present disclosure, the first PD controller IC  402   a  may be electrically connected with the second PD controller IC  402   b . The master IC  406  may be omitted and the first PD controller IC  402   a  may be directly connected with the second PD controller IC  402   b.    
     As an example, the logic circuit  400  may include the Cypress® EZ-PD™ CCG3PA USB Type-C port controller. Thus, the output voltage received at the logic circuit may range from 3.0V to 24.5V DC, and the logic circuit  400  may tolerate 30V of output voltage. Thus, the output voltage may range from 3.0V DC to 30V DC. 
     According to an aspect of the present disclosure, a method for charging a plurality of electronic devices using a USB charging system includes providing AC power from a power source  110  to an AC/DC converter  200 . The method includes receiving, at the AC/DC converter  200 , the AC power from the power source  100 . The AC/DC converter  200  includes a plurality of power converters and a plurality of power supply outputs electrically coupled to the plurality of power converters, respectively. Each of the plurality of power converters is configured to convert the AC power to a plurality of different DC output voltages. The method includes receiving, at the power source  100  (e.g., at the AC/DC converter  200 ), direct feedback from a logic circuit  400  in direct electrical communication with the AC/DC converter  200 , and outputting a particular DC output voltage from the AC/DC converter  200  in response to the direct feedback received. The logic circuit  400  is in electrical communication with a plurality of charging ports (e.g., any of USB charging ports  190   a  and/or  190   b , Line-Voltage Ports  2591   a  and/or  2591   b , and/or additional charging ports having substantially the same configuration). The method includes delivering the particular DC output voltage to each of the plurality of electronic devices respectively connected with each of the plurality of charging ports. 
     The method of charging a plurality of electronic devices according to an aspect of the present disclosure includes detecting, by the logic circuit  400 , a temperature of two or more charging ports and reducing a wattage delivered to a particular charging port of the plurality of charging ports if a temperature detected in the particular charging port of the plurality of charging ports exceeds a predetermined threshold. The reduced wattage (e.g., reduced to below 30 watts) delivered to the particular charging port of the plurality of charging ports may be maintained at an above-zero level until a temperature of the particular charging port of the plurality of charging ports is reduced below a second predetermined threshold. Multiple temperature thresholds can be employed, each indicating a reduced wattage delivered to the particular charging port of the plurality of charging ports. A supply of power to a particular charging port may also be completely cut off and reduced to zero if a predetermined temperature threshold is reached, or if a predetermined threshold is reached multiple times within a predetermined time period. 
     Alternatively, or in conjunction with detecting a temperature of two or more charging ports, the logic circuit  400  can detect a current drawn by two or more charging ports of the plurality of charging ports (e.g., a current drawn by each line voltage port) and reduce a current drawn by a particular charging port of the plurality of charging ports if a temperature determined in the particular charging port of the plurality of charging ports exceeds a predetermined threshold and/or if a current drawn by a particular line voltage port exceeds a predetermined threshold. 
     The temperature in a particular charging port may also be reduced using a thermally conductive housing (see, e.g., thermally conductive housings  2701  or  2801  in  FIGS. 27 and 28 , respectively) in thermal contact with the plurality of charging ports. The thermally conductive housing transfers heat away from the charging ports of the plurality of charging ports to reduce a temperature of the charging ports of the plurality of charging ports. As an example, the thermally conductive housing may have a molecular structure configured to draw heat along the directional arrows illustrated in  FIGS. 27-28 . The molecular structure of the thermally conductive housing may draw heat along a path of least resistance away from the charging ports to reduce the temperature of the charging ports. The thermally conductive housing may include or be formed of aluminum. The thermally conductive housing may be in thermal contact with the power supply  110 , the plurality of charging ports and the logic circuit  400 . The thermally conductive housing is configured to transfer heat away from at least one of the power supply  110 , the charging ports of the plurality of charging ports, or the logic circuit  400  to reduce a temperature of the USB charging system (e.g., USB charging system  2700  or  2800 ). The thermally conductive housing may be configured to transfer heat away from any suitable heat generating, or heat retaining component, to reduce a temperature of any other suitable component or to reduce the temperature of the device as a whole. 
     As an example, the electronic device receiving the output voltage may be a Smartphone, computer, Tablet or any other electronic device. The output voltage may be used to charge a battery of the electronic device. 
     According to an aspect of the present disclosure, each respective electronic device connected with each respective charging port of the plurality of charging ports may receive a same output voltage. For example, a single desired output voltage may be output to the logic circuit  400  and each of a plurality of devices respectively connected with a plurality of charging ports may receive a same output power. 
     According to an aspect of the present disclosure, each of the plurality of charging ports may be a USB Type-C charging port. According to an aspect of the present disclosure, voltages of the plurality of output voltages may range from substantially 5 volts to substantially 20 volts. However, exemplary embodiments of the present disclosure are not limited thereto, and other desired voltages may be output to the charging ports. As an example, logic circuit  400  may provide direct feedback to the power supply to output one of 5, 9 or 15 volts of direct current. 
     As an example, an output voltage of 5 Volts (direct current DC) at a current of 6 Amps provides 30 Watts according to the above-noted formula. 
     According to an aspect of the present disclosure, the logic circuit may include a first power delivery (PD) controller integrated circuit (IC)  402   a  and a second PD controller IC  402   b . The first PD controller IC  402   a  may be electrically connected with a first charging port  190   a  of the plurality of charging ports. The second PD controller IC  402   b  may be electrically connected with a second charging port  190   b  of the plurality of charging ports. 
     According to an aspect of the present disclosure, the first PD controller IC  402   a  may be electrically connected with the second PD controller IC  402   b . The master IC  406  may be omitted and the first PD controller IC  402   a  may be directly connected with the second PD controller IC  402   b.    
     As an example, the logic circuit  400  may include the Cypress® EZ-PD™ USB Type-C port controller. Thus, the output voltage received at the logic circuit may range from 3.0V to 24.5V DC, and the logic circuit  400  may tolerate 30V of output voltage. 
       FIG. 16  depicts an exemplary schematic of an AC/DC converter  200  in accordance with the present disclosure. The AC/DC converter  200  typically takes an input from an AC power source  110  and processes it through the bridge rectifier  202 . Bridge rectifier  202  converts AC to DC voltage by providing full wave rectification from a two-wire AC input. The polarity of the output is the same regardless of the polarity of the input. The DC signal created by the bridge rectifier  202  may have some amount of ripple on it, which is filtered out by filtering capacitors and inductors coupled to the output terminals of the bridge rectifier  202 . The DC voltage is then stepped down with a transformer  204  and further filtered by a filter  206 . A flyback converter  208  may be used to regulate the DC voltage. 
       FIG. 17  depicts a block diagram of a USB power delivery system architecture including a direct feedback system and thermistors in accordance with an exemplary embodiment of the disclosure. 
     Referring to  FIG. 17 , according to an aspect of the present disclosure, a USB charging system  1700  may include a thermistor (e.g., thermistor  1701  or thermistor  1702 ) electrically connected with at least one PD controller IC (e.g.,  402   a  or  402   b ). The USB charging system  1700  may be substantially the same as the USB charging system  1300  described in more detail above, and thus duplicative descriptions may be omitted below. The thermistor may be configured to reduce power delivery to the at least one charging port of the plurality of charging ports in response to a temperature exceeding a first predetermined threshold. The reduced power delivery to the at least one charging port of the plurality of charging ports may be maintained at an above-zero level until a temperature of the charging port is reduced below a second predetermined threshold. Thus, use of the thermistor may prevent a binary on/off power delivery scheme in which power is completely cut off in the event of excess heat generation. As a result, a reduced power output may be applied to a USB charging port while a temperature level is reduced. This may allow continuous charging to occur (at a reduced rate) for a connected device, even when a temperature above a predetermined threshold occurs. As a result, charging times of the connected device may be reduced, and overall power use efficiency may be increased when compared with a binary on/off power delivery scheme. 
       FIG. 18  depicts exemplary mechanical and electrical connections between a power board and a logic board in accordance with an exemplary embodiment of the disclosure.  FIG. 19  is a cross-sectional view along lines  18   a - 18   b  of a mechanical connection between a power board and a logic board in accordance with an exemplary embodiment of the disclosure. 
     Referring to  FIGS. 18 and 19 , a mechanical connection is illustrated between a power board  1902  and a logic board  1901 . The mechanical connection is formed by a projection  1903  extending from the power board  1902  through an aperture in the logic board  1901 . Thus, strength and rigidity of a mechanical connection between the power board  1902  and the logic board  1901  may be increased. This may prevent movement between the boards, thus decreasing a failure rate of connections between the boards. 
     Referring to  FIG. 18 , an electrical connection between the power board  1902  and the logic board  1901  formed through a post may be divided into a split connection (i.e., two separated electrical connections) in a single post. For example, a first electrical connection  1801  may be separated from a second electrical connection  1802  between the power board  1902  and the logic board  1901  by a first slit  1803  and a second split  1804  in the post. Thus, two separate electrical connections may be formed in a relatively small amount of space. Thus, a size of the power board  1902  and/or the logic board  1901  may be reduced, and an overall size of a USB receptacle employing the power board  1902  and the logic board  1901  may be reduced. 
       FIGS. 20A and 20B  each depict an exemplary system for upgrading firmware of a USB receptacle in accordance with an exemplary embodiment of the disclosure.  FIG. 21  depicts an exemplary system for wirelessly upgrading firmware of a USB receptacle in accordance with an exemplary embodiment of the disclosure. 
     As an example, the logic circuit  2006  described in more detail below with reference to  FIGS. 20A, 20B and 21  may include the Cypress® EZ-PD™ CCG3PA USB Type-C port controller. Thus, the logic circuit may have a fully programmable power supply mode, and firmware that may be modified and custom tailored, as desired. Unless otherwise specified below, the logic circuit  2006  described in more detail below may have substantially the same configuration as the logic circuit  400  described in more detail above, and thus duplicative descriptions may be omitted below. Unless otherwise specified below, the USB charging port  2008  described in more detail below may have substantially the same configuration as the charging ports (e.g.,  190   a  and/or  190   b ) described in more detail above, and thus duplicative descriptions may be omitted below. 
     Referring to  FIG. 20A , according to an aspect of the present disclosure, a system for modifying firmware includes a USB receptacle having a logic circuit  2006  including at least one power delivery (PD) controller integrated circuit (IC)  2007 . The logic circuit  2006  has a first memory storing firmware configured to control the logic circuit  2006 . At least one USB charging port  2008  is in communication with the logic circuit  2006 . However, exemplary embodiments of the present disclosure are not limited to a single USB charging port. For example, as described herein, any number of desired charging ports may be included in the USB receptacle and may be controlled by the logic circuit  2006 . 
     The firmware stored on the first memory of the logic circuit  2006  is modified by communicably coupling a device  2001  to the at least one USB charging port  2008 . While the device may be a Smartphone or a laptop computer, exemplary embodiment are not limited thereto and other devices such as a tablet, desktop computer or other desired devices may be employed to update firmware, as described herein. The device  2001  has a processor and a second memory storing computer instructions configured to modify the firmware stored on the first memory of the logic circuit  2006 . The firmware stored on the first memory of the logic circuit  2006  is modified by transmitting computer instructions from the device  2001  to the logic circuit  2006 . 
     According to an aspect of the present disclosure, the device  2001  may include a device operating system  2003  configured to control the functionality of the device  2001  and may include hardware (e.g., Type-C controller hardware)  2004  configured to interface with and control a transfer of a firmware modification from the device  2001  to the logic circuit  2006 . 
     According to an aspect of the present disclosure, the device  2001  may be a Smartphone, a USB drive, a Tablet, or a computer. The Smartphone, USB drive, tablet or computer may have a firmware update application thereon. The firmware update application is configured to modify the firmware stored on the first memory of the logic circuit  2006 . Thus, the device  2001  may be able to access and modify firmware of the logic circuit  2006  without the use of external or specialized hardware between the device  2001  and the logic circuit  2006 . This may be achieved by directly accessing the logic circuit  2006  using any device that is capable of connecting and interfacing with a USB charging port of the USB receptacle including the logic circuit  2006 . 
     According to an aspect of the present disclosure, the USB charging port may be a USB Type-C charging port. 
     According to an aspect of the present disclosure, the device may be communicably coupled to the at least one USB charging port through a USB cable. The USB cable may be a USB Type-C cable. The USB Type-C cable may be a generic cable that does not include specialized hardware configured to interface with the logic circuit  2006 . 
     Referring to  FIG. 20B , the device  2001  may be communicably coupled to the USB charging port  2008  of the logic circuit  2006  via an external hardware module  2010 . The hardware module  2010  may include a cable  2009  connected with the device  2001  and a USB cable connected with the USB charging port  2008 . The external hardware  2010  may include a processor and a memory storing computer instructions thereon. The computer instructions stored on the external hardware may be configured to modify the firmware stored on the first memory of the logic circuit  2006 . 
     A system and method for wirelessly updating firmware is described in more detail below. Unless otherwise specified below, the logic circuit  2106  described in more detail below may be substantially the same as the logic circuit  2006  described in more detail above, and thus duplicative descriptions may be omitted below. Unless otherwise specified below, the device  2101  described in more detail below may be substantially the same as the device  2001  described in more detail above, and thus duplicative descriptions may be omitted below. 
     Referring to  FIG. 21 , according to an aspect of the present disclosure, a system for wirelessly modifying firmware includes a USB receptacle having a logic circuit  2106  including at least one power delivery (PD) controller integrated circuit (IC)  2107 . The logic circuit  2106  has a first memory storing firmware configured to control the logic circuit  2106 . The logic circuit  2106  has a first wireless antenna  2111 . The firmware stored on the first memory of the logic circuit  2106  is modified by communicably coupling a device  2101  to the logic circuit through a wireless connection  2105 . The device  2101  has a second wireless antenna  2110  configured to communicate with the first wireless antenna  2111  of the logic circuit  2106 . The device  2101  has a processor and a second memory storing computer instructions configured to modify the firmware stored on the first memory of the logic circuit  2106 . The firmware stored on the first memory of the logic circuit  2106  is modified by wirelessly transmitting computer instructions from the device  2101  to the logic circuit  2106 . 
     According to an aspect of the present disclosure, the USB receptacle including the logic circuit  2106  may also include a USB charging port  2108  in communication with the logic circuit  2106 . The device  2101  may include a device operating system  2103  configured to control the functionality of the device  2101  and may include hardware (e.g., Type-C controller hardware)  2104  configured to interface with and control a transfer of a firmware modification from the device  2101  to the logic circuit  2106 . 
     According to an aspect of the present disclosure, the first wireless antenna  2111  of the logic circuit  2106  may communicate with the second wireless antenna  2110  of the device  2101  through a Bluetooth or WiFi signal. Thus, the wireless antennas described herein may be Bluetooth and/or WiFi capable wireless antennas. Alternatively, the wireless antennas described herein may communicate with a cellular communication network and may pull down firmware updates from the cloud and modify the firmware of the logic circuit  2106  using a firmware modification pulled down from the cloud and transferred to the logic circuit  2106 . 
     According to an aspect of the present disclosure, the device  2101  may be a Smartphone, a USB drive, a Tablet, or a computer. The device may have a USB firmware update application  2102  thereon. The firmware update application  2102  is configured to modify the firmware stored on the first memory of the logic circuit  2106 . Thus, the firmware of the logic circuit  2106  may be updated wirelessly without a connection with a USB port in communication with the logic circuit  2106 . 
       FIG. 22  is a block diagram of a USB Type-A charging port, a USB Type-C charging port, a single AC-DC power supply and a single voltage regulator in accordance with an exemplary embodiment of the disclosure. 
       FIG. 22  depicts a relatively high power USB charger receptacle (e.g., with an AC-DC power supply providing an output voltage of greater than 5 volts) with the ability to charge devices with multiple output voltages through a USB Type-A port or a USB Type-C port. The USB Type-C port will meet the USB PD specification and be used to charge devices at multiple output voltages for an output voltage of relatively high power (e.g., above 5 volts and as high as substantially 20 volts). As an example, a constant 5 volt output voltage may be provided by the USB Type-A port, while a higher output voltage is provided by the USB Type-C port. 
     Referring to  FIG. 22 , according to an aspect of the present disclosure, a USB charging system includes an AC-DC power supply  2201  configured to output a plurality of output voltages. A USB Type-A charging port  2202  is electrically connected with the AC-DC power supply  2201 . The USB Type-A charging port  2202  is configured to provide a first output voltage to a first electronic device. A USB Type-C charging port  2203  is electrically connected with the AC-DC power supply  2201 . The USB Type-C charging port  2203  is configured to provide a second output voltage to a second electronic device. A voltage regulator  2204  is electrically connected with the AC-DC power supply  2201  and the USB Type-A charging port  2202 . The voltage regulator  2204  is configured to maintain the first output voltage provided by the USB Type-A charging port  2202 . A switch  2205  is electrically connected with the AC-DC power supply  2201  and the USB Type-A charging port  2202 . The switch  2205  is configured to bypass the voltage regulator  2204 . A logic circuit (see, e.g.,  FIG. 13 ) is in electrical communication with the voltage regulator  2204  and the switch  2205 . The logic circuit is configured to enable or disable the voltage regulator  2204  by opening or closing the switch  2205 . 
     According to an aspect of the present disclosure, each respective electronic device connected with each respective charging port (e.g., ports  2202  or  2203 ) may receive a different output voltage. Voltages of the plurality of output voltages may range from substantially 5 volts to substantially 20 volts. 
     According to an aspect of the present disclosure, the first output voltage may be a fixed output voltage (e.g., 5 volts), and the second output voltage may be a variable output voltage (e.g. a voltage of from above 5 volts to substantially 20 volts). The variable output voltage may be determined by the electronic device connected with the USB Type-C port  2203 . 
     According to an aspect of the present disclosure, the voltage regulator may be a linear voltage regulator or a DC-DC converter. 
       FIG. 24  is a block diagram of two USB Type-C charging ports and a single voltage regulator in accordance with an exemplary embodiment of the disclosure. 
       FIG. 24  depicts two independent voltage USB Type-C ports with a single DC-DC converter stage. This will allow the AC to DC power supply output voltage to be higher than the output voltage of one of the USB ports. The AC to DC power supply will be connected to a voltage regulator (e.g., a DC to DC converter or a linear voltage regulator) and one or more switches to the USB ports. This will allow the receptacle to have two different DC charging voltages at the same time. The DC to DC converter or linear voltage regulator and the switches will be controlled by the same microcontroller to verify that there is never more than the safe charging voltage at the USB port. The microcontroller will also verify that the receptacle will never advertise a higher charging power than the AC to DC power supply can provide. While two USB Type-C charging ports are illustrated and described, exemplary embodiments of the present disclosure are not limited thereto, and additional charging ports may be employed. 
     Referring to  FIG. 24 , according to an aspect of the present disclosure, a USB charging system includes an AC-DC power supply  2401  configured to output a plurality of output voltages. A first USB Type-C charging port  2402  is electrically connected with the AC-DC power supply  2401 . The first USB Type-C charging port  2402  is configured to provide a first output voltage to a first electronic device. A second USB Type-C charging port  2403  is electrically connected with the AC-DC power supply  2401 . The second USB Type-C charging port  2403  is configured to provide a second output voltage to a second electronic device. A voltage regulator  2404  is electrically connected with the AC-DC power supply  2401  and the first or second USB Type-C charging ports  2402  or  2403 . The voltage regulator  2404  is configured to regulate the first or second output voltages of the first or second USB Type-C charging ports  2402  or  2403 . A first switch  2405  is electrically connected with the AC-DC power supply  2401  and the first USB Type-C charging port  2402 . The first switch  2405  is configured to bypass the voltage regulator  2404 . A second switch  2406  is electrically connected with the AC-DC power supply  2401  and the second USB Type-C charging port  2403 . The second switch  2406  is configured to bypass the voltage regulator  2404 . A logic circuit (see, e.g.,  FIG. 13 ) is in electrical communication with the voltage regulator  2404  and the first and second switches  2405  and  2406 . The logic circuit is configured to enable or disable the voltage regulator  2404  by opening or closing the first or second switches  2405  or  2406 . 
     According to an aspect of the present disclosure, a third switch  2407  may be electrically connected with the AC-DC power supply  2401  and the first USB Type-C charging port  2402 . The third switch  2407  may be configured to activate the voltage regulator  2404 . A fourth switch  2408  may be electrically connected with the AC-DC power supply  2401  and the second USB Type-C charging port  2403 . The fourth switch  2408  may be configured to activate the voltage regulator  2404 . 
     According to an aspect of the present disclosure, each of the first, second, third and fourth switches  2405 - 2408  may be configured to be individually enabled or disabled by the logic circuit. 
       FIG. 23  is a flowchart of an exemplary algorithm employed by a logic circuit of the USB charging systems of  FIGS. 22 and 24 . 
     Referring to  FIG. 23 , an exemplary software flow chart for control of the USB Type A and Type C ports with independent voltages is illustrated. Independent voltages may be achieved by providing a DC-DC converter parallel to a pass-through switch. When the voltage at the output of power supply is greater than 5V (safe limit for Type-A), the DC-DC converter is used to convert the higher voltage to 5V for the Type-A port. If voltage at the output of power supply is 5V, then the pass-through switch is used to supply 5V to USB Type A. 
     Referring again to  FIG. 17 , and to  FIGS. 25-28 , USB charging systems  2500 ,  2600 ,  2700  and  2800  are described. The USB charging systems  2500 ,  2600 ,  2700  and  2800  may be substantially the same as the USB charging systems  1300  or  1700  described in more detail above unless otherwise indicated, and thus duplicative descriptions may be omitted below. 
     According to an aspect of the present disclosure, the logic circuit  400  is configured to regulate a wattage delivered to two or more charging ports of the plurality of charging ports (e.g., any of USB charging ports  190   a  and/or  190   b , and/or additional charging ports having substantially the same configuration). The plurality of charging ports described herein may include a USB Type-A port, or a USB Type-C port, or a Line-Voltage port ( 2591   a  and/or  2591 ) in any desired combination. The logic circuit  400  is configured to detect a temperature of two or more charging ports of the plurality of charging ports. The logic circuit  400  is configured to reduce a wattage delivered to a particular charging port of the plurality of charging ports if a temperature detected in the particular charging port of the plurality of charging ports exceeds a predetermined threshold. The logic circuit  400  may be in electrical communication with any of thermistors  2501 ,  2502 ,  2503  and/or  2504 . The thermistors are configured to detect a temperature of each charging port and communicate the detected temperature to the logic circuit  400 . The thermistors  2501 ,  2502 ,  2503  and  2504  may be substantially the same as the thermistors (e.g., thermistor  1701  or thermistor  1702 ) described above with reference to  FIG. 17  unless otherwise indicated, and thus duplicative descriptions may be omitted herein. Instead of thermistors, any suitable temperature sensors may be used, non-limiting examples of which are thermocouples, resistance temperature detectors (RTDs), silicon bandgap temperature sensors. Additionally, a temperature sensor may be integral to one or more integrated circuit chips, controllers, logic circuits, or the like. 
     As an example, a maximum wattage deliverable to each charging port of the plurality of charging ports is at least 30 watts. Thus, a wattage in excess of 30 watts may be applied to one or more of the charging ports to relatively rapidly charge an electronic device connected with a particular charging port. The systems and methods described herein allow for an increased wattage to be applied (e.g., in excess of 30 watts) to reduce a charging time of an electronic device, while also dynamically reducing the wattage applied for some periods of time to maintain a desired temperature at the charging port. This allows a connected electronic device to be charged in a minimal amount of time, while also regulating a temperature of the corresponding charging port (e.g., to prevent overheating or exceeding a permitted temperature threshold). As described herein, reducing the power applied to charging port below 30 watts, but above 0 watts, allows the electronic device to be charged at a reduced rate, while allowing the temperature of the corresponding charging port to be reduced. As described herein, the temperature of a particular charging port may be reduced through passive and/or active processes. For example, passive cooling may be employed by using a thermally conductive housing, and active cooling may be employed by using a fan configured to blow air within, or exhaust from, a charging system described herein. 
     According to an aspect of the present disclosure, the thermistors  2501 ,  2502 ,  2503  and  2504  are each configured to collect temperature data for the USB charging system (e.g., USB charging systems  2500 ,  2600 ,  2700  or  2800 ) and communicate the temperature data to the logic circuit  400 . 
     The logic circuit  400  may control a combination of USB Type C ports (e.g., 2 USB Type C Ports  190   a ,  190   b , as illustrated), Line-Voltage Ports (e.g., 2 Line-Voltage Ports  2591   a ,  2591   b ), and/or USB Type A ports (not shown). 
     As an example, 30 watts may be provided to one or more of the USB Type C ports (e.g., an output voltage of 5 Volts (direct current DC) at a current of 6 Amps provides 30 Watts). However, power greater than 30 watts may be provided to one or more of the USB Type C ports (e.g., by increasing the output voltage above 5 Volts, or the current above 6 Amps). 
     According to an aspect of the present disclosure, the logic circuit  400  is configured to detect a current drawn by two or more charging ports of the plurality of charging ports. The logic circuit  400  is configured to reduce a current drawn by a particular charging port of the plurality of charging ports if a temperature determined in the particular charging port of the plurality of charging ports exceeds a predetermined threshold. Detecting a current drawn by two or more charging ports may be performed as an alternative method to determining a temperature of two or more charging ports, or may be employed simultaneously with directly measuring a temperature of each charging port. The current drawn by each charging port may be determined using current sensors  2601 ,  2602 ,  2603  and/or  2604 . The current sensors are each in electrical communication with the logic circuit  400 . Each charging port may be connected with both a thermistor and a current sensor. 
     As an example, each of the current sensors  2601 ,  2602 ,  2603  and  2604  may be a coil (e.g. a toroid coil), Hall Effect sensor, or a voltage over a known resistance (e.g. a shunt). 
     Referring particularly to  FIGS. 27-28 , a thermally conductive housing (e.g., thermally conductive housing  2701  or  2801 ) is in thermal contact with the plurality of charging ports. The thermally conductive housing is configured to transfer heat away from the charging ports of the plurality of charging ports to reduce a temperature of the charging ports of the plurality of charging ports. 
     According to an aspect of the present disclosure, the thermally conductive housing includes a metal or other high thermal conductivity material. The thermally conductive housing can passively transfer heat along a desired direction through conduction and/or convection. As an example, heat may be transferred through a metal housing initially through conduction and subsequently through convection. 
     As an example, the thermally conductive housing may have a molecular structure arranged to draw heat (e.g., to passively draw heat) along the directional arrows illustrated in  FIGS. 27-28 . The molecular structure of the thermally conductive housing may draw heat along a path of least resistance away from the charging ports to reduce the temperature of the charging ports. For example, a combination of metals having different thermal conductivity characteristics may be included in the thermally conductive housing to control a path of least resistance along which heat generated in at least one charging part can be passively transferred. A combination of copper, aluminum, brass, steel and/or bronze may be included in the thermally conductive housing. Additionally, the thermally conductive housing may draw heat along a plurality of paths according to the relative thermal resistance of each of such paths. 
     Referring to  FIGS. 29, 30, and 31A to 31E , a USB charging system  2900  and method for dynamic load sharing is described. The USB charging system  2900  can be employed to dynamically charge multiple electronic devices (e.g., two electronic devices  2910   a  and  2910   b ) at relatively high wattage (e.g., at 60 watts of combined total output) to reduce an amount of overall time for charging the multiple electronic devices by allocating power to the device in need of more power to reach a full charge. The systems and methods described with reference to  FIGS. 29, 30, and 31A to 31  are deployable as firmware of a USB charging receptacle (e.g., a 60 watt USB charging device) having at least two dynamically controlled USB charging ports (e.g., USB Type-C charging ports). While a 60 watt USB charging system is described as an example, the systems and methods described herein are similarly applicable to USB charging systems above or below 60 watts. 
     When electronic devices  2910   a  and  2910   b  are respectively connected with and charging via first and second USB charging ports  190   a  and  190   b  and one device reaches its maximum state of charge (SoC), the current supplied to that one device is reduced and the current supplied to the other device is increased. Thus, the device that is yet to reach its maximum SoC when another device has already reached its maximum SoC gets to charge faster thus reducing an overall charging time for multiple electronic devices. 
     According to an aspect of the present disclosure, the logic circuit  400  is configured to monitor a state of charge of devices  2910   a  and  2910   b  connected with charging ports  190   a  and  190   b , respectively. The logic circuit  400  is configured to dynamically regulate a wattage delivered each of devices  2910   a  and  2910   b . As an example, a maximum combined wattage deliverable to the first and second charging ports  190   a  and  190   b  is about 60 watts. 
     The logic circuit  400  is configured to reduce a wattage delivered to first charging port  190   a  when a state of charge of the first device  2910   a  connected with the first charging port  190   a  exceeds a predetermined threshold (e.g., when a maximum state of charge or a near maximum state of charge is reached). The logic circuit  400  is configured to increase a wattage delivered to the second device  2910   b  connected with the second charging port  190   b  when the state of the charge of the first device  2910   a  exceeds the predetermined threshold. 
     After a reduction/increase in supplied current, new power delivery outputs (PDOs) are advertised to ports  190   a  and  190   b  depending on the output current/power of ports  190   a  and  190   b . Thus, there is no need to disconnect/reconnect any device to advertise new PDOs to ports  190   a  or  190   b . In both ports  190   a ,  190   b  charging voltages and currents are changed (by advertising new PDOs) based on measuring the SoC of the electronic devices connected in real time. An exemplary algorithm for implementing dynamic load sharing in USB charging system  2900  is described in more detail below with reference to  FIGS. 30 and 31A to 31E . 
     As an example, a reduced wattage delivered to the first device  2910   a  connected with the first charging port  190   a  is maintained at an above-zero level, by the logic circuit  400 , when the state of charge of the first device  2910   a  is below a maximum state of charge for the first device  2910   a . Thus, a minimal wattage may be applied to the first charging port  190   a , while a significantly higher wattage is applied to the second charging port  190   b , or the reverse may be applied if second device  2910   b  reaches the predetermined charging threshold (e.g., the maximum state of charge of the second device  2910   b ) before the first device  2910   a . This process allows a nearly charged device to continue charging while a second device at a lower level of charge is charged at a faster rate, thus reducing an overall amount of time needed to charge two devices. 
     Alternatively, the reduced wattage delivered to the first device  2910   a  connected with the first charging port  190   a  can be maintained at 0 watts, by the logic circuit  400 , when the state of charge of the first device  2910   a  reaches the maximum state of charge for the first device  2910   a . Thus, in this scenario the increased wattage delivered to the second device  2910   b  is maintained at about 60 watts by the logic circuit  400 . 
     According to an aspect of the present disclosure, a first current sensor  2901  in electrical communication with the logic circuit  400  is connected with the first charging port  190   a . A second current sensor  2902  in electrical communication with the logic circuit  400  is connected with the second charging port  190   b . The first current sensor  2901  communicates data of a first load current in the first current sensor  2901  to the logic circuit  400 . The second current sensor  2902  communicates data of a second load current in the second current sensor  2902  to the logic circuit  400 . Thus, the logic circuit  400  can continuously receive data of a current received in the first and second charging ports  190   a  and  190   b  (e.g., in real-time). Alternatively, the logic circuit  400  can periodically receive data of a current received in the first and second charging ports  190   a  and  190   b  (e.g., by sampling). 
     Referring particularly to  FIGS. 30 and 31A to 31E , an exemplary algorithm  3100  employing hysteresis bands  3000  is described. The algorithm described below can be employed by firmware of a USB charging receptacle, as described herein. 
     In an exemplary algorithm, three power delivery outputs (PDOs) can be advertised to each of two charging ports (see, e.g., USB ports  190   a  and  190   b ). The three PDOs that are advertised depend on load power consumed by a port nearing full charge (i.e., a “lower power port”). The difference between the 5V3 A PDO and the regular PDO is that in 5V, 3 A PDO, the lower power port nearing full charge is always advertised with only the 5V, 3 A PDO whereas in the regular PDO, both the ports are advertised with at least one PDO other than 5V, 3A. 
     If at least one port is charging at 5V, 3 A, then the corresponding device connected with that port is already in the 5V, 3 A PDO state. The other states where both electronic devices get charged at identical voltages (other than 5V) are regular PDO states. 
     When an electronic device connected with a charging port is operating in a regular PDO state, the firmware checks periodically if the power consumed by one of the ports is less than 6 W. If this proposition is true, then a counter is initialized to 3 and is decremented. If this proposition is false, then the counter is reinitialized to 3. If the counter equals 0 then the lower power port is advertised only with 5V, 3 A PDO. If the higher power port is charging at 20V, 1.5 A, then it get advertised with 15V, 2 A, 9V, 2.5 A and 5V, 3 A PDOs. If the higher power port is charging at “x” V(x=15V, 9V or 5V) then it is re-advertised with “x” V PDO and 5V, 3 A PDO. This condition is referred to as a 5V, 3 A condition. 
     In the 5V, 3 A condition, the firmware checks at a predetermined rate if the lower power port is within two thresholds. (a). P(lower power port) &gt;4 W and (b). P(lower power port) &lt;7 W 
     If the power P(lower power port)&lt;4 W, then a counter is initialized to 3 and is decremented. If the counter equals 0, then the lower power port is advertised with 5V, 900 mA PDO. The higher power port is advertised with 20V, 1.5 A, 15V, 2 A, 9V, 2.5 A and 5V, 3A PDOs. This is referred to as Reduced PDO state. At the Reduced PDO state, the counter is reset to 0. 
     In the 5V, 3 A condition, if the Power P(lower power port) &gt;7 W at least once, then converter is switched back to the regular PDO state. The counter is reset to 0. 
     In the Reduced PDO state, the firmware checks at a predetermined rate P(lower power port) &gt;7 W at least once, then converter is switched back to the regular PDO state. The firmware also checks if Power P(lower power port) &gt;5 W at least once, then converter is switched back to the 5V, 3 A state. The counter is reset to 0. 
     While several embodiments of the disclosure have been shown in the drawings, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Any combination of the above embodiments is also envisioned and is within the scope of the appended claims. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular embodiments. Those skilled in the art will envision other modifications within the scope of the claims appended hereto.