Multiple output charging system and controller

A multi-port charging system includes a controller having a power input terminal coupled to a DC power output of a converter, multiple power output terminals coupled to the power input terminal, and a communications input terminal. The system includes multiple charger ports, the respective charger ports having a charging power line coupled to a respective one of the power output terminals, and a communications line coupled to the communications input terminal. The controller is configured to control the state of the control output terminal to set a voltage of the DC power output according to a selected highest common compatible voltage of one or more sink devices coupled to one or more respective ones of the charger ports.

BACKGROUND

Charging systems are useful in a variety of applications to provide convenient charging for personal devices, such as smart phones, tablets, laptop computers, etc. Due to the proliferation of battery-operated personal devices, it is desirable to provide charging systems able to charge multiple devices concurrently, for example, in automotive or home applications. Universal serial bus (USB) technology allows DC charging. USB devices are typically designed to operate at a default charging condition with 5 V and 0.5 A. Fast charging implementations, such as USB power delivery (USB-PD) allow power supplies (e.g., sources) and loads (e.g., sinks) to negotiate higher charging voltages and/or charging current levels, such as 3-21 V and 0-5 A. Multiple output or multi-port chargers provide charger ports and corresponding DC voltage supplies (e.g., AC to DC or DC to DC converters) that may adapt voltage and/or current of a given charger port to accommodate sink devices or loads that can operate at different voltages and/or currents, in order to facilitate fast charging.

However, such multi-port solutions for concurrently charging n sink devices require one converter per charger port, and each converter must have a sufficient power rating to provide desirable fast charging. This adds to charging system cost, particularly where fewer than n sink devices are typically connected at a given time and/or common charging conditions do not utilize the full power budget of the converter. In addition to cost considerations, certain applications (e.g., portable battery-operated USB chargers, automotive vehicle USB chargers, etc.) have power and size design limitations, where small low-power charging systems are needed. However, multi-port charging systems with n DC to DC converters often have a system power budget below the maximum power of the combined converters, where the total system power budget Ptot<Σ [DC to DC_(1)+DC to DC_(2)+DC to DC_(n)], resulting in poor power and system space utilization.

SUMMARY

A controller includes a power input terminal, an integer number N power output terminals coupled to the power input terminal, a communications input terminal, and a control output terminal having an integer number M states, where N is greater than 1 and M is greater than 1. The respective power output terminals are adapted to be coupled to respective charging power lines of N charger ports, and the communications input terminal is adapted to be coupled to communications lines of the respective charger ports. The power input terminal is adapted to be coupled to a power output of a converter, and the control output terminal adapted to be coupled to a control input of the converter.

In one example, the controller is an integrated circuit. In one example, the controller includes a logic circuit, such as a processor or a state machine, having a communications interface coupled to the communications input terminal, and a voltage select output coupled to the control output terminal. In one example, the controller includes a switch circuit having N switches coupled between the power input terminal and a respective one of the power output terminals, and the logic circuit includes N switch control outputs coupled to control terminals of respective ones of the switches. In one example, the logic circuit is configured to control the state of the control output terminal responsive to a highest common compatible voltage of one or more sink devices coupled to one or more respective ones of the power output terminals. In one implementation, the logic circuit is configured to select the highest common compatible voltage of the one or more sink devices responsive to sink device parameters received in communications signals of the communications input terminal, and a power budget of a converter coupled to the power input terminal.

In accordance with further aspects, a controller includes a power input terminal, N power output terminals coupled to the power input terminal, where N is an integer greater than 1, as well as a communications input terminal, a control output terminal, and a logic circuit. The control output terminal has M states, where M is an integer greater than 1. The logic circuit is configured to receive communications signals of the communications input terminal, where the communications signals have sink device parameters of one or more sink devices coupled to one or more respective ones of the power output terminals. The logic circuit is further configured to select a highest common compatible voltage of the sink device parameters according to a power budget of a converter coupled to the power input terminal. The logic circuit is also configured to control the state of the control output terminal according to the selected highest common compatible voltage of the sink device parameters to cause the converter to deliver the selected highest common compatible voltage at the power input terminal.

In one example, the logic circuit is configured to control the state of the control output terminal by generating a voltage select signal at the control output terminal, where a state of the generated voltage select signal represents the selected highest common compatible voltage of the sink device parameters. In one implementation, the logic circuit is configured to generate the voltage select signal as a digital signal having a selected one of M states.

In one example, the logic circuit includes a processor coupled to a memory, the memory configured to store the sink device parameters and the power budget. In one example, the logic circuit includes a state machine.

In one example, the logic circuit is configured to select an updated highest common compatible voltage of the sink device parameters according to the power budget responsive to connection and/or disconnection of one or more sink devices to or from one or more respective ones of the power output terminals.

In one example, the controller includes a switch circuit having N switches coupled between the power input terminal and a respective one of the power output terminals, and the logic circuit includes N switch control outputs coupled to control terminals of respective ones of the switches. In one implementation, the logic circuit is configured to generate switching control signals at the switch control outputs to selectively couple the power input terminal to selected ones of the power output terminals to which a sink device is connected.

In accordance with another aspect, a charging system includes a converter, a controller, and N charger ports, where N is an integer greater than 1. The converter has a power output, and a control input. The controller has a power input terminal, N power output terminals, a communications input terminal, and a control output terminal. The power input terminal is coupled to the power output of the converter, and the respective power output terminals are coupled to the power input terminal. The control output terminal is adapted to be coupled to a converter, and the control output terminal has M states, where M is an integer greater than 1. The respective charger ports have a charging power line coupled to a respective one of the power output terminals, and a communications line coupled to the communications input terminal. The controller is configured to control the state of the control output terminal to set a voltage of the converter power output according to a selected highest common compatible voltage of one or more sink devices coupled to one or more respective ones of the charger ports.

In one example, the controller is configured to receive communications signals of the communications input terminal, where the communications signals have sink device parameters of the sink device or devices. The controller is configured to select the highest common compatible voltage of the sink device parameters according to a power budget of the converter, and generate a voltage select signal at the control output terminal, where a state of the generated voltage select signal represents the selected highest common compatible voltage of the sink device parameters.

In one example, the charging system includes a switch circuit having N switches coupled between the power input terminal and a respective one of the power output terminals. In one implementation, the controller includes switch control outputs coupled to the control terminals of respective ones of the switches, and the controller is configured to generate switching control signals at the switch control outputs to selectively couple the power input terminal to selected ones of the power output terminals to which a sink device is connected.

DETAILED DESCRIPTION

In the drawings, like reference numerals refer to like elements throughout, and the various features are not necessarily drawn to scale. Also, the term “couple” or “couples” includes indirect or direct electrical or mechanical connection or combinations thereof. For example, if a first device couples to or is coupled with a second device, that connection may be through a direct electrical connection, or through an indirect electrical connection via one or more intervening devices and connections. One or more operational characteristics of various circuits, systems and/or components are hereinafter described in the context of functions which in some cases result from configuration and/or interconnection of various structures when circuitry is powered and operating.

Described examples include charging systems and charging controllers that provide a solution in which multiple ports are available for intelligent charging of connected sink devices using a single converter with a DC power output, and the controller sets the DC voltage of the converter according to a highest common compatible voltage of device parameters of the connected sink device parameters, and according to a power budget of the converter. Example solutions can be useful in USB-PD or other charger applications to leverage the functionality of a single output DC to DC, while reducing the size, cost and complexity of multi-port charges that have two or more converters. Moreover, the described solutions facilitate economical choice of converter size and power budget according to expected usage, while accommodating charging when most or all ports are being used.

FIG.1shows a multi-port charging system100(e.g., labeled CHARGER inFIG.1) for charging one or more battery operated devices. In one example, the charging system100is a stand-alone product, such as a portable battery-operated charger for charging one or more USB compatible devices (e.g., referred to as sink devices). In another example, the charging system100is integrated into a host device, such as a laptop or desktop computer, an automotive vehicle, an industrial system (not shown).

The charging system100includes a single converter101having a power input102adapted to be coupled to a supply103. In one example, the converter101is an AC to DC converter having a single or multiphase AC input102coupled to receive an AC input voltage signal VIN from an AC supply103. In another example, the converter101is a DC to DC converter having a DC input to receive to receive a DC input voltage signal VIN from the supply103. In one implementation, the charging system is a portable multi-port USB charger and the supply103is a battery or other DC voltage supply with features for charging the on-board battery from an AC source (not shown). In another example, the charging system100is an automotive accessory with multiple USB charging ports accessible from a passenger compartment, and the supply103is a 12 V battery. In another example, the charging system100is part of an industrial system, and the supply103is a 24 V DC source. In one example, the charging system100operates from a variety of connectable DC supplies103, with output voltages that vary widely (e.g., 3-30 V) and the converter101has a wide input voltage range to accommodate coupling the power input102to different supplies103with different DC output voltages.

The converter101also includes a power output104that provides a DC output voltage signal VO. The converter101further includes a control input105configured to receive a voltage select signal VSEL. In one example, the control input105is adapted to receive an analog voltage or current signal VSEL. In another example, the control input105is adapted to receive a single or multi-bit digital signal VSEL. The received voltage select signal VSEL in one example has an integer number of M states, where M is greater than 1. The converter101responds to the state of the voltage select signal VSEL to set the voltage VO of the power output104. In one example, the converter101is configured to provide selectable DC output voltages VO of 0, 5, 9, 12, 15, and 20 V according to the state of the received voltage select signal VSEL (e.g., M=6).

The example charging system100includes a transformer or inductor circuit106coupled to the power output104of the converter101, as well as a filter circuit107coupled to an output of the inductor or transformer circuit106. In other examples, one or both of the inductor or transformer circuit106and the filter circuit107can be omitted.

The charging system100includes a controller108. In one example, the controller108is an integrated circuit (IC). The controller108includes a power input terminal109. The power input terminal109is adapted to be coupled to a power output104of a converter101to receive a DC voltage signal PPHV. In one example, the charging system100is or includes a printed circuit board, and the controller108includes a conductive IC terminal (e.g., pin, pad, etc.) soldered to a conductive pad of the printed circuit board. In one implementation, the converter101is also an integrated circuit with output terminals104soldered to the circuit board to form an electrical connection, direct or indirect, to the power input terminal109of the controller108. The power input terminal109, in this regard, can be directly or indirectly coupled to the converter power output104, with one or more intervening devices or circuits (e.g., inductor or transformer circuit106, filter circuit107) connected therebetween.

The controller108also includes an integer number of N power output terminals110, where N is greater than 1. The respective power output terminals110are coupled, directly or indirectly to the power input terminal109. The controller108has a ground or reference voltage connection terminal111coupled to the negative DC output of the converter101, directly or through the circuits106and107. The controller108also includes a communications input terminal112and a control output terminal113. The control output terminal113is adapted to be coupled to the control input105of the converter101, for example, by circuit board connections of a printed circuit board. The control output terminal113has M states.

The controller108also includes a logic circuit114with a communications interface coupled to the communications input terminal112, and a voltage select output coupled to the control output terminal113. In one example, logic circuit114includes a processor (e.g., a microprocessor, microcontroller, FPGA, programmable circuit, etc.) coupled to a memory115. The memory115in one example stores processor-executable program instructions to implement the various charging functions and features detailed herein as well as other functions associated with operating the converter101, selectively coupling connected sink devices to the power input terminal109, communicating with connected sink devices, etc. In addition, the logic circuit114in one example communicates with other external devices, such as a host processor (not shown). The charging system100in certain examples includes user interface features, such as a user interface with a display and keyboard or touchscreen features to provide indications to users and to receive user inputs (not shown). In addition, the memory115stores parameters associated with charging capabilities of connected sink devices, as well as a power budget associated with the converter101. In another example, the logic circuit114includes a state machine. The logic circuit114communicates with connected sink devices via the communications input terminal112.

In one example, the controller108includes a switch circuit116having an integer number of N switches S1, S2, . . . , SN, where N is greater than 1. The respective switches S1, S2, . . . , SN include a first terminal coupled to the power input terminal109, a second terminal coupled to a respective one of the power output terminals110, and a control terminal. The switches in one example are transistors, such as bipolar transistors, field effect transistors (FETs). In other examples, the switches are relays, such as solid-state relays, etc. In this example, the logic circuit114includes N switch control outputs117coupled to the control terminals of respective ones of the switches S1, S2, . . . , SN. The logic circuit114generates switching control signals SC at the switch control outputs117to selectively couple the power input terminal109to selected ones of the power output terminals110.

The charging system100includes N charger ports. Only three charger ports120,130, and140are illustrated inFIG.1. The charger ports120,130, and140include respective charging power lines122,132, and142coupled to a respective one of the power output terminals110. In one example, the ports120,130, and140are USB ports with USB compatible connectors that include corresponding charging power lines122,132, and142to convey respective bus voltage signals VBUS1, VBUS2, and VBUSN from the corresponding power output terminals110of the controller to charge a connected sink device. In addition, the charger ports120,130, and140include respective communications lines124,134, and144coupled to the communications input terminal112.FIG.1shows one example, in which a first sink device126(e.g., smart phone) is connected via a USB cable128to the first port120, a second sink device136is connected via a USB cable138to the second port130, and a another sink device146is connected via a cable148to the Nthport140. The USB connectors in one example also include a corresponding ground pin (labeled GND inFIG.1), which are connected to the reference voltage connection terminal111. In addition, the example USB connectors of the charging ports120,130, and140are Type-C plugs that include two configuration channel lines CC1and CC2, one or both of which are connected to the respective communications lines124,134, and144(labeled CC inFIG.1). In one example, the logic circuit114includes N communications input terminals112as shown inFIG.1. In another implementation, the communications lines124,134, and144are connected in a single communications line112, which is coupled to a communications interface of the logic circuit114.

In one example, the logic circuit114communicates with connected sink devices126,136, and146as these are coupled to respective ones of the charger ports120,130, and140. The connected sink devices126,136, and146report their corresponding sink device parameters121,131, and141, which are received by the logic circuit114in communications signals of the communications input terminal112. The logic circuit114in one example stores the sink device parameters121,131, and141in the memory115. The memory115in one example stores a power budget150of the converter101that is coupled to the power input terminal109. In operation, the logic circuit114controls the state of the control output terminal113responsive to a highest common compatible voltage of one or more sink devices126,136,146coupled to one or more respective ones of the power output terminals110. The sink device parameters121,131, and141specify one or more compatible charging voltages and corresponding compatible current levels at which the corresponding sink devices126,136, and146can be charged.

In the example ofFIG.1, the first sink device126has parameters121stored in the memory115that inform the logic circuit114that the sink device126can be charged at a first voltage V1and corresponding first current I1, as well as at a second voltage/current pair V2/I2, etc. The parameters121indicate an integer number “i” voltage current pairs including a final ithpair Vi, Ii) for the sink device126coupled to the first charger port120. The second connected sink device136has parameters131stored in the memory115, including an integer number “j” voltage/current value pairs V1/I1, V2/I2, . . . , Vj/Ij. The final connected sink device146has parameters141stored in the memory115, including an integer number “k” voltage/current value pairs V1/I1, V2/I2, . . . , Vk/Ik. The power budget150in one example stores M selectable DC output voltage values for the voltage VO of the power output104of the converter101. In one example, with M=6, the power budget150stores values corresponding to selectable DC output voltage values VO=0, 5, 9, 12, 15, and 20 V, as well as corresponding current values or corresponding power values from which the logic circuit114determines a maximum charging current available for the M selectable voltages.

In operation, the logic circuit114controls the state of the control output terminal113to set the DC output voltage VO of the power output104according to a selected highest common compatible voltage of one or more sink devices126,136, and146coupled to one or more respective ones of the charger ports120,130, and140. The converter101operates at a selected DC output voltage according to the state of the received voltage select signal VSEL. In one example, the logic circuit114selects the highest common compatible voltage of the one or more sink devices126,136,146responsive to the sink device parameters121,131, and141received in communications signals of the communications input terminal112, and the power budget150of a converter101. The logic circuit114controls the state of the control output terminal113by generating the voltage select signal VSEL having a state that represents the selected highest common compatible voltage of the sink device parameters121,131, and141. In one example, the logic circuit114selects an updated highest common compatible voltage of the sink device parameters121,131, and141according to the power budget150in response to connection of one or more sink devices to one or more respective ones of the power output terminals110, or disconnection of one or more sink devices from one or more respective ones of the power output terminals110. In this manner, the logic circuit adapts the operation to provide a best charging condition for the currently coupled sink devices.

Referring also toFIGS.2and3,FIG.2shows a method200for charging one or more sink devices126,136,146using a single converter101, andFIG.3shows a signal diagram of example signals in the charging system ofFIG.1during operation of the logic circuit114according to the method200. In one implementation, the logic circuit114executes program instructions from the memory115in order to perform the acts or events of the method200. In another implementation, the logic circuit114includes a state machine that implements the method200. The method200as described hereinafter in association with the charging system100ofFIG.1. The method200begins at202with power up of the multiport charging system100. In one example, the logic circuit114monitors the communications input terminal112for communications signals from any connected sink device. The logic circuit114determines at204whether one or more sink devices are coupled to the charger ports. If not (NO at204), the logic circuit114continues to monitor the communications input terminal112for communications signals indicating coupling of one or more sink devices.

Once one or more sink devices are coupled to respective ones of the charger ports (YES at204), the logic circuit114adjusts the converter output voltage VO to a default value (e.g., 5 V) at205, and the logic circuit114determines at206whether multiple sink devices are coupled to respective charger ports. If only a single sink device is coupled (NO at206), the logic circuit114receives voltage and current capabilities from the connected sink device at208, and stores the received sink device parameters (e.g.,121) in the memory115. At210, the logic circuit114of the charging system100selects (e.g., evaluates) the highest compatible voltage within the converter power budget115. Where only a single sink device is connected, the logic circuit114in one example selects the highest compatible voltage from the corresponding connected sink device parameters121, and determines whether the corresponding voltage is possible according to the list of M selectable DC output voltages of the power budget150. If not, the logic circuit114evaluates the next highest voltage, and determines whether that voltage is possible using the converter101. Once the logic circuit114determines an available charging voltage of the sink device parameters121, the logic circuit114determines whether the associated charging current of the sink device parameters121is within the power budget150. If so, the logic circuit114selects this as the highest compatible voltage within the converter our budget150at210.

At212, logic circuit114negotiates with the connected sink device to cause the connected sink device to operate at the selected charging voltage, for example, using communications via the communications input terminal112. At214, the logic circuit114adjusts the converter101to the selected voltage. In one example, the logic circuit114controls the state of the control output terminal113by generating the voltage select signal VSEL having a state that represents the selected highest common compatible voltage at214in order to adjust the output voltage VO at the power output104of the converter101. In one example, at216inFIG.2, the logic circuit114generates an associated one of the switching control signals SC at the switch control output117to selectively couple the power input terminal109to a selected one of the power output terminals110to which the sink device (e.g.,126) is coupled.

The method200in this example continues at218, where the logic circuit114monitors the communications input terminal112for communications signals indicating coupling of one or more sink devices to other charger ports, and/or for loss of communications signaling indicating that the currently coupled sink device has been disconnected from the associated charger port. In response to new connection and/or disconnection (YES at218), the method200returns to204and206as described above, where the logic circuit114determines whether any sink devices are coupled to the charging system100(YES at204), and whether more than one sink devices are coupled to the charging system100(YES at206).

In response to detection of more than one sink devices being coupled to the charging system100(YES at206), the logic circuit114receives voltage and current capabilities (e.g., sink device parameters) from all currently coupled sink devices at220, and selects (e.g., evaluates) a highest common compatible voltage within the converter power budget150at222. In one example, the logic circuit114determines the highest voltage at222that is selectable for operation by the converter101, and that is common to all the stored sink device parameters (e.g.,121,131, and141in the case where three sink devices126,136, and146are coupled as shown inFIG.1). In addition, the logic circuit114determines at222whether the sum of the associated charging current from the sink device parameters at that DC output voltage are within the power budget150of the converter101. If not, the logic circuit114likewise evaluates the next lowest voltage that is selectable for operation of the converter101and that is common to all the sink device parameters for currently coupled sink devices.

In one example, the converter101is selected such that its power budget150allows charging of all coupled sink devices (e.g.,126,136, . . . ,146) when all the charger ports120,130, . . . ,140are in use, for example, at the default USB charging voltage of 5 V at 0.5 A. In another example, a smaller converter101is used, and the logic circuit114selectively implements a priority algorithm to selectively charge less than all coupled sink devices when all the charger ports are used. In one implementation, the logic circuit114implements a first in, first out priority algorithm, for example, where one or more most recently connected sink devices is/are temporarily denied charging service (e.g., by the logic circuit114opening the associated switch of the switch circuit116) while the earliest connected devices are charged.

At223, the logic circuit114determines whether there is a match that exceeds 5 V. If so (YES at223), the process200proceeds to224. At224inFIG.2, the logic circuit114negotiates with the connected sink device to cause the connected sink devices to operate as the selected highest common compatible charging voltage using communications via the communications input terminal112. At226, the logic circuit114adjusts the converter101to the selected voltage by generating the voltage select signal VSEL having a state that represents the selected highest common compatible voltage to cause the converter101to adjust the output voltage VO at the power output104. If there is no match that exceeds 5 V (e.g., NO at223), the charger maintains the default 5 V output voltage VO at the power output104. In one example, the logic circuit114generates associated ones of the switching control signals SC at the switch control output117at228to selectively couple the power input terminal109to a selected one of the power output terminals110to which the sink device (e.g.,126) is coupled. Thereafter, the multi-port charging continues at218, and the logic circuit114monitors the communications input terminal112for communications signals indicating coupling of one or more sink devices to other charger ports, and/or for loss of communications signaling indicating disconnection of one or more currently coupled sink devices from the associated charger ports.

In one implementation, the logic circuit114generates the voltage select signal VSEL to cause the converter101to output a predetermined voltage (e.g., 5 V) during negotiation and evaluation to select and implement the highest common compatible voltage, and the logic circuit115activates the associated switch is of the switch circuit116by generating the corresponding switching control signals SC at the switch control output117to couple the respective charging power lines (e.g.,122,132, and/or142) and the corresponding power output terminals110to the power input terminal109during the negotiation and evaluation operations.

In another implementation, the logic circuit114generates the switching control signals SC to disconnect all the respective charging power lines and the power output terminals110from the power input terminal109during negotiation and adjustment of the converter101according to the voltage select signal VSEL, and changes the switching control signals SC to selectively couple selected ones of the power output terminals110to the power input terminal109once the selected charging voltage has been established by the converter101.

FIG.3shows a signal diagram300with example curves310-313,321-323, and331-333that show example signals in the charging system100as a function of time during operation of the logic circuit114according to the method200. The curved310shows the DC output voltage VO at the power output104of the converter101, and the curve311shows the bus voltage signal VBUS1at the charging power line122of the charger port120. The curve312shows communications signals (CC1) of the communications line124of the first charger port120, and the curve313shows the state (e.g., ON or OFF) of the first switch S1. The signal diagram300also includes curves321-323corresponding to the second charger port130, including the curve321that shows the second bus voltage signal VBUS2at the charging power line132, the curve322that shows communications signals (CC2) of the second communications line134, and the curve323that shows the on/off state of the second switch S2. The curves331-333correspond to the final charger port140, where the curve331shows the bus voltage signal VBUSN at the charging power line142, the curve332shows communications signals (CC3) of the communications line144, and the curve333shows the on/off state of the switch SN.

In the example ofFIG.3, no sink devices are coupled to the charging system100at time T0, and the first sink device126is coupled via the cable128to the first charger port120at a time prior to T1. The logic circuit114generates the voltage select signal VSEL from T0through T1to cause the converter101to output 0 V from T0through T1. The logic circuit114receives communications from the first sink device126(curve312) prior to T1. The logic circuit114responds by setting the converter voltage (curve310) to 5 V at time T1. In this example, the logic circuit114also closes the first switch S1(curve313) at time T1, and the connected sink device126begins charging at the default voltage value of 5 V. From T1to time T2in this example, the logic circuit114receives the sink device parameters121from the sink device126, evaluates the parameters121to determine the highest compatible voltage for charging the sink device126, referred to as negotiation operation (e.g.,208-216inFIG.2). In the illustrated example, the first sink device126is capable of charging at 15 V, and the logic circuit114determines that this is an available voltage within the capabilities of the converter101. At time T2, the logic circuit114generates the voltage select signal VSEL with a state that causes the converter101to output 15 V (curve310), and the switch circuit116couples this charging voltage to the charging power line122of the charger port120(VBUS1, curve311). The device126charges at 15 V from T2to T3.

After T2and before T3, the second sink device136is coupled via the cable138to the second charger port130, and the logic circuit114receives communications from the sink device136(curve322) prior to T3. The logic circuit114responds by resetting the converter voltage (curve310) to the default 5 V value at time T3, and the logic circuit114closes the second switch S2(curve323) at time T3such that the newly connected sink device136and the previously coupled sink device126charge at the default voltage value of 5 V. Between times T3to T4, the logic circuit114receives the sink device parameters131from the newly connected sink device126, and evaluates the parameters121and131to determine the highest common compatible voltage for charging the sink devices126and136(e.g., negotiation operation at220-228inFIG.2). In this example, the second sink device136is not capable of 15 V charging, but both devices126and136can be charged at 12 V, with charging current requirements within the power budget150of the converter101. By evaluating the sink device parameters121and131, along with the power budget150, the logic circuit114selects the highest common compatible voltage of 12 V (222inFIG.2). At T4, the logic circuit114negotiates with the connected sink device to cause the coupled devices126and136to this selected voltage (224inFIG.2), and generates the voltage select signal VSEL (226) with a state that causes the converter101to output 12 V (curve310). In this configuration, the sink devices126and136charged at 12 V from T4to T5inFIG.3.

The example continues with the logic circuit114receiving communications prior to T5from a newly coupled sink device146, which has been coupled via the cable148to the charger port140inFIG.1. At time T5, the logic circuit114generates the voltage select signal VSEL to reset the converter voltage (curve310) to the default 5 V value, and closes the switch SN (curve333) such that the sink devices126,136, and146charge at the default voltage value of 5 V from T5to T6. Between T5and T6, the logic circuit114receives the sink device parameters141from the newly connected sink device146, and evaluates the parameters121,131, and141to determine the highest common compatible voltage for concurrently charging the three coupled sink devices126,136, and146(e.g., negotiation operation at220-228inFIG.2). In this example, the sink device146, although capable of charging at 12 V, would add excessive charging current requirements that would exceed the power budget150of the converter101. However, the sink device parameters121,131, and141indicate that the coupled sink devices126,136, and146can each accommodate charging at 9 V within the power budget150of the converter101.

The logic circuit114selects this voltage as the highest common compatible voltage (e.g.,222inFIG.2). At T6, the logic circuit114negotiates with the connected sink devices to cause the coupled devices126,136, and146to the 9 V selected voltage (224inFIG.2), and generates the voltage select signal VSEL (226) with a state that causes the converter101to output 9 V (curve310). In this configuration, the sink devices126,136, and146are charged at 9 V from T6to T7inFIG.3.

At T7inFIG.3, the logic circuit114detects that the first sink device126has been disconnected (e.g., decoupled) from the first charger port120(e.g., YES at218inFIG.2). In response, the logic circuit114turns the first switch S1off (curve313) at T7, and resets the converter voltage VO to the default value of 5 V. Between T7and time T8, the logic circuit114reevaluates the charger voltage in view of the sink device parameters131and141of the respective remaining sink devices136and146. In this example, both the remaining sink devices136and146can operate at a charger voltage of 15 V within the power budget150of the converter101, and the logic circuit114selects 15 V as the highest common compatible voltage (222inFIG.2). The logic circuit negotiates with the connected sink devices to cause the connected devices136and146to charge at this voltage (224), and generates the voltage select signal VSEL (226) to adjust the DC output voltage VO of the converter101to 15 V at T8. The coupled sink devices136and146charge at 15 V from T8to T9.

Prior to time T9, the logic circuit114in this example receives communications (curve312) from another sink device (not shown inFIG.1) that has been coupled to the first charger port120between T8and T9. At T8, the logic circuit114generates the voltage select signal VSEL to reset the converter voltage (curve310) to the default 5 V value, and closes the switch S1(curve313) such that the three coupled sink devices charge at 5 V from T9to T10. Between T9and T10, the logic circuit114receives the sink device parameters from the newly connected sink device coupled to charger port120, and evaluates the sink device parameters of all three coupled sink devices in order to determine the highest common compatible voltage (e.g., negotiation operation at220-228inFIG.2). In this example, the newly coupled sink device is not capable of fast charging, and can only charge at 5 V. The logic circuit114accordingly selects 5 V (222inFIG.2) is the highest common compatible voltage. At T10, the logic circuit114negotiates with the connected sink devices to cause the coupled devices to the 5 V selected voltage (224inFIG.2), and generates the voltage select signal VSEL (226) with a state that causes the converter101to output 5 V (curve310). In this configuration, the sink devices continue charging at 5 V after T10inFIG.3.

FIG.4shows a multi-port USB-PD implementation of the charging system100with a single adjustable converter101according to another embodiment. In this example, the charging system100includes USB Type C socket connectors100that individually have bus voltage (VBUS) terminals, positive and negative data terminals D+ and D−, configuration channel lines CC1and CC2, and a ground terminal (GND). The converter101in this example includes a switching converter circuit402that converts AC input power to DC output power, or converts DC input power to DC output power, including the power output terminals104as described above. The converter101includes a feedback circuit404that provides a feedback voltage signal FB to the switching converter circuit402. In operation, the switching converter circuit402regulates the DC output voltage VO at the power output104by comparing the feedback voltage signal FB to an internal reference signal (not shown). The feedback circuit404includes a resistive voltage divider circuit formed by an upper feedback resistor and an integer number M lower feedback resistors. The lower feedback resistors in this example are coupled between the upper feedback resistor and the reference voltage connection terminal111coupled to the negative DC output of the converter101, including switches between the lower feedback resistors and the reference voltage connection terminal111. In operation, the logic circuit114provides a multi-bit digital voltage select signal VSEL having M control signals to operate individual switches of the feedback circuit404. The lower feedback resistors have different values corresponding to feedback voltage signal amplitudes that drive the regulated DC output voltage VO to the designated M values for controlled selection by the logic circuit114.

The described examples can be applied to portable and integrated USB chargers for home use or integration into automotive or industrial systems, as well as in other charging applications to charge multiple sink devices using a single adjustable AC to DC or DC to DC converter. The described controller sets the DC output voltage of the converter according to the highest common compatible voltage of device parameters of the connected sink device parameters, and according to a power budget of the converter. Example solutions can be useful in USB-PD or other charger applications to leverage the functionality of a single output DC to DC, while reducing the size, cost and complexity of multi-port charges that have two or more converters. In a dual port USB-PD implementation example with a DC to DC converter101capable of 3-21 V at 0-6 A, a first sink device connects to Port A and reports its sink capabilities (e.g., 5 V at 3 A; 9 V at 2.3 A; and 20 V at 1 A). The logic circuit115and the sink device negotiate a power delivery contract of 20 V at 1 A. Thereafter, a second sink device connects to Port B. The logic circuit114communicates using the USB Power Delivery protocol and negotiates with the connected sink device to cause the sink device attached to Port A to 5 V at 3 A. The logic circuit114then establishes a connection with the Port B sink device at 5 V at 3 A, and requests the sink device parameters from the sink device coupled to Port B. The second sink device reports capabilities of 5 V at 1.5 A; 9 V at 1.8 A; and 15 V at 1.2 A. The 9 V option is available for both devices. The logic circuit114then negotiates ports A and B to 9 V, resulting in the first sink device of Port A establishing a 9 V at 2 A contract and the second device of Port B establishing a 9 V at 1 A contract. Both sink devices are charged from the common DC to DC converter101that operates with a DC output voltage VO of 9 V and the total current for port A and port B is below the maximum rating of the source (e.g., 2.3 A+1.8 A=4.1 A<6 A capability of the power budget150). In certain examples, the logic circuit114operates within the boundaries of the USB-PD specifications to interrogate multiple USB sink connections and map a voltage and current profile common to all connected sink devices. In accordance with the USB-PD specifications, all sink devices are presumed to be operable for charging at the default value of 5 V. Described examples of the controllers108and systems100use the USB-PD controller108to use a single DC to DC or other converter101and establish contracts with all connected USB sink devices without exceeding either the individual capabilities of each sink device or the total power available from the DC to DC converter101.

Modifications are possible in the described examples, and other implementations are possible, within the scope of the claims.