Patent Description:
Power requirements for modern electronics devices are increasing very rapidly; e.g., devices having larger displays, LTE devices (radios, modems, etc.), multicore processors, and so on. To maintain acceptable up times, such devices utilize batteries with higher capacity. In such systems, battery charging times tend to be very long when conventional power sources are used. The reasons include: (<NUM>) limited power capability (USB 5V/<NUM>. 8A max); and (<NUM>) voltage headroom issues between input power source and battery. Furthermore, many readily available power sources (e.g., monitors, notebooks, etc.) cannot be utilized because of their high-voltage operation vs. what the portable device can tolerate. Implementing a solution that requires the use of a secondary portable device connector significantly increases solution and consumer cost (proprietary connector, wall adapter, etc.).

With battery capacities increasing, 5V input voltage does not provide enough voltage headroom to achieve sufficiently high charge currents due to cable, connector, PCB, and charger impedances. Many batteries now have a float voltage of <NUM>. 35V which makes this issue worse, especially since the trend is toward the use of higher voltages. For example, a <NUM> stack provides about <NUM>. 4V or <NUM>. 7V, thus requiring a voltage higher than 5V to charge efficiently. Attention is drawn to <CIT> describing a battery charger may include a charger connector to be coupled to a corresponding device connector of a portable device including a rechargeable battery. The battery charger may also include a charging circuit connected to the charger connector, and a controller connected to the charger connector and the charging circuit. The controller may be for causing a portable device connected to the charger connector to identify its corresponding portable device type and its corresponding rechargeable battery type from among a plurality of different portable device types and different battery types, and for causing the charging circuit to charge the rechargeable battery based thereon. Attention is further drawn to <CIT> describing a method and system for supplying power to a host via a USB port. The power is transmitted to the host using the standard VBUS and GND lines that are part of standard USB cables and connectors. The peripheral device includes a special USB descriptor block. During the standard enumeration process, the host reads this USB descriptor block and recognizes that the device can provide power to the host. A set feature command is used to start the power transmission to the host.

Further embodiments of the invention are described in the dependent claims.

A circuit for charging a battery from an external device may include a detection circuit to detect an electrical configuration of the signal lines that comprise a cable for connecting the circuit to the external device. A configuration circuit may assert one of several electrical configurations on the signal lines in response to the detection circuit. In response, the external device may supply a voltage on a power line at a voltage level corresponding to the electrical configuration asserted on the signal lines.

In some embodiments, the circuit operates in accordance with the USB Battery Charging Specification. The power line may be VBUS and the signal lines may be the D+ and D- lines as set forth in the USB Specification. The circuit can be backward compatible with industry standards, allowing for existing standardized connectors and cabling, while at the same time allowing for a greater range of operational voltages beyond the standard 5V operating level of the USB specification.

The following detailed description and accompanying drawings provide a better understanding of the nature and advantages of the present disclosure.

In the following description, for purposes of explanation, numerous examples and specific details are set forth in order to provide a thorough understanding of the present disclosure. It will be evident, however, to one skilled in the art that the present disclosure as expressed in the claims may include some or all of the features in these examples alone or in combination with other features described below, and may further include modifications and equivalents of the features and concepts described herein.

<FIG> shows a circuit <NUM> in accordance with embodiments of the present disclosure. The circuit <NUM> may be included in a portable device <NUM> such as a smartphone, computer tablet, and so on. The portable device <NUM> may include a battery <NUM> to power the portable device. In some embodiments, the battery <NUM> may be a rechargeable battery that the circuit <NUM> may charge. The battery <NUM> may be a single cell configuration, or may be a multi-cell stack.

The portable device <NUM> may be connected to an external device <NUM>. In some embodiments, the external device <NUM> may be an alternating current (AC) adapter such as a wall adapter. In other embodiments, the external device <NUM> may be an electronic device that can supply power to the portable device. For example, the external device <NUM> may be laptop computer that supplies power from its own battery pack or by virtue of being connected to an AC supply.

The portable device <NUM> and external device <NUM> may have respective connectors <NUM> and <NUM>. A cable <NUM> may electrically connect the portable device <NUM> and the external device <NUM>.

In some embodiments, the circuit <NUM> may include charging circuitry <NUM>, detection circuitry <NUM>, control circuitry <NUM>, and configuration circuitry <NUM>. The circuit <NUM> may include a power bus <NUM> for electrical connection to a power line in the cable <NUM>. The circuit <NUM> may further include a signal bus <NUM> comprising a plurality of signal bus lines for electrical connection to signal lines in the cable <NUM>. The number of signal bus lines comprising the signal bus <NUM> may vary from one embodiment to another. For example, a design based on the USB Specification defines two signal bus lines, D+ and D-, while another design may employ more than two signal bus lines.

In some embodiments, the charging circuitry <NUM> may be connected to the power bus <NUM> to transfer power from a voltage supplied by the external device <NUM> to charge the battery <NUM>; e.g., via a coupling 102a. The charging circuitry <NUM> may be of any known design, such as a switching charger design for instance. In some embodiments, the coupling 102a may comprise battery terminals that the battery <NUM> can connect to. In other embodiments, the charging circuitry <NUM> may be connected to any load other than a battery. In still other embodiments, the charging circuitry <NUM> may be connected to both a load and to a battery (e.g., battery <NUM>).

The detection circuitry <NUM> may be connected to the signal bus <NUM> to detect various electrical configurations on the signal bus lines comprising the signal bus. The external device <NUM> may assert an electrical configuration on the signal lines of the cable <NUM> that the detection circuitry <NUM> may detect on the signal bus <NUM>. In some embodiments, the detection circuitry <NUM> may comprise voltage comparators, current sensors, and the like to detect an electrical configuration on the signal bus <NUM>.

An electrical configuration asserted on the signal bus lines of the signal bus <NUM> may be a voltage level (including ground potential) asserted one or more signal bus lines, or multiple voltage levels asserted on several signal bus lines. An electrical configuration may also be one or more currents flowing respectively in one or more of the signal bus lines. In some embodiments, an electrical configuration may be asserted by connecting one or more of the signal bus lines to a resistor (or other passive device such as a capacitor or inductor), or connecting together one or more of the signal bus lines. In some embodiments, an electrical configuration may be asserted using a combination of voltage, current flows, and/or resistor (or other passive device).

In some embodiments, the electrical configuration asserted on the signal bus lines of the signal bus <NUM> is analog in nature. In other aspects useful for the understanding of the invention and not corresponding to the claims, the electrical configuration can be communicated through or by the signal bus <NUM>. For example, the electrical configuration may be digital in nature where the signal bus lines of the signal bus <NUM> communicate digital information. Although the remainder of the present disclosure will mainly describe electrical configurations as analog signals, one of ordinary skill in the art will appreciate that the electrical configuration may be asserted or detected in various ways on the signal bus <NUM>.

As mentioned above, an electrical configuration may be asserted on the signal bus lines of the signal bus <NUM> by an external device <NUM> electrically connected to the signal bus via cable <NUM>. Similarly, an electrical configuration may be asserted on the signal bus lines by the configuration circuitry <NUM>. In some embodiments, for example, the configuration circuitry <NUM> may include voltage sources, current sources, switches (e.g., MOS switches), passive devices (e.g., a resistor), and the like to assert some combination of voltage levels and/or current levels on one or more of the signal bus lines that comprise the signal bus <NUM>.

The control circuitry <NUM> may be connected to receive one or more signals 104a from the detection circuitry <NUM>. The signals 104a may be indicative of a detected electrical configuration asserted on the signal bus <NUM> by the external device <NUM>. The control circuitry <NUM> may be connected to provide one or more control signals 106a to the configuration circuitry <NUM> in order to assert a particular electrical configuration on the signal bus <NUM>.

The portable device <NUM> may further comprise device electronics (load) <NUM>. For example, if the portable device <NUM> is a computer tablet, the device electronics <NUM> may comprise the components such as a processor, memory, display, etc. The device electronics <NUM> may be connected to the power bus <NUM> via connector 114a to draw power received by the circuit <NUM>.

The external device <NUM> may include a voltage selector <NUM> and a power section <NUM>, in addition to other electronic circuitry (not shown) comprising the external device. For example, the external device <NUM> may be laptop computer, or the external device may be a power supply (e.g., an AC adapter), etc. The power circuit <NUM> may provide a voltage at one of several selectable voltage levels that can be delivered to the portable device <NUM> via cable <NUM>. For example, the external device <NUM> may include a power bus <NUM> that is connected to the power line in the cable <NUM>. The voltage selector <NUM> may connect the voltage produced by the power section <NUM> to the power bus <NUM>. In some embodiments, the voltage selector <NUM> may be connected to a signal bus <NUM> comprising a plurality of signal bus lines, which may be electrically connected to signal bus <NUM> via cable <NUM>. As will be explained in more detail below, the voltage selector <NUM> may detect or sense an electrical configuration on the signal bus <NUM> and control or otherwise signal the power section <NUM> to output a voltage level that corresponds to the detected electrical configuration. The voltage selector <NUM> may comprise digital logic, analog circuitry, or a combination of digital and analog components to detect or sense the electrical configuration on the signal bus <NUM>.

One of ordinary skill will appreciate that embodiments according to the present disclosure include any electronic device. In more general embodiments, the portable device <NUM> may be any electronic device and the circuit <NUM> may omit the charging circuitry <NUM>. Referring to <FIG>, for example, an electronic device <NUM>' may comprise a circuit <NUM>' in accordance with the present disclosure that does not necessarily include circuitry for charging a battery. For example, the electronic device <NUM>' may not use a battery or otherwise does not provide for a rechargeable battery, and thus may omit battery charging circuitry. As in <FIG>, the device electronics <NUM> in the electronic device <NUM>' may be powered by a voltage on the power bus <NUM>.

As another example, <FIG> shows an embodiment in which an electronic device <NUM>" may provide the voltage that is received on the power bus <NUM> to another electronic device 10a; e.g., using a connection <NUM>. In some embodiments, electronic component <NUM>" may be an electrical connection between the power bus <NUM> and the connection <NUM>. In other embodiments, the electronic component <NUM>" may include device electronics for the electronic device <NUM>" that are powered by the power bus <NUM>.

<FIG> illustrates an operation of the circuit <NUM> in conjunction with an external device according to principles of the present disclosure. At block <NUM>, the circuit <NUM> may detect an attachment to an external device (e.g., <NUM>, <FIG>). For example, the circuit <NUM> may include circuitry (not shown) to detect the presence of a voltage on the power bus <NUM> that is provided by the external device <NUM>.

At block <NUM>, the circuit <NUM> may determine what kind of external device is attached to the circuit. For example, the external device <NUM> may be a conventional power supply that supplies a single output voltage. In accordance with the present disclosure, the circuit may be attached to an external device that is capable of supplying a voltage at any one of several selectable voltage levels.

In some embodiments, the external device <NUM> may assert an electrical configuration on the signal bus <NUM> to indicate what kind of device it is. Merely to illustrate, suppose the signal bus <NUM> comprises two signal bus lines. An electrical configuration on the two signal bus lines may be asserted by the external device <NUM> (e.g., using voltage selector <NUM>) by connecting a resistor between two of the signal bus lines and applying a predetermined direct current (DC) voltage level on the other signal bus line. Another electrical configuration might involve applying two different DC voltage levels on each of the signal bus lines, and so on.

The detection circuitry <NUM> may sense the particular electrical configuration asserted by the external device by sensing the signal bus lines comprising the signal bus <NUM>. Based on the electrical configuration sensed by the detection circuitry <NUM>, signal(s) 104a may be provided to the control circuitry <NUM> to indicate the kind of external device that is attached to the circuit <NUM>. In accordance with the present disclosure, if at block <NUM>, the electrical configuration sensed at block <NUM> indicates that the external device <NUM> is of a first kind (e.g., has selectable voltage levels) then additional processing may be performed, as described below. If the external device <NUM> is not of the first kind, then the circuit <NUM> may operate under the assumption that it is attached to an external device that is capable of outputting a single voltage level, and at block <NUM> receive the voltage from the external device. Accordingly, at block <NUM>, the voltage received by the circuit <NUM> may then be used to charge a battery (e.g., <NUM>, <FIG>) or provide power to a load (e.g., <NUM>).

If, at block <NUM>, the external device <NUM> is determined to be of the first kind where the external device supports multiple selectable output voltage levels, then in accordance with principles of the present disclosure, the circuit <NUM> at block <NUM> may use the configuration circuitry <NUM> to assert an electrical configuration on the signal bus <NUM> from among several predefined electrical configurations. In some embodiments, for example, the circuit <NUM> may support different kinds of battery <NUM>, having different voltage levels for proper battery charging. For instance, some batteries may be charged with <NUM> volts, other batteries may require <NUM> volts, <NUM> volts, <NUM> volts, and so on. Likewise, different types of loads <NUM> may operate at different voltage levels. Accordingly, the control circuitry <NUM> may generate signals 106a to operate the configuration circuitry <NUM> to assert an electrical configuration on the signal bus <NUM> that corresponds to a specified voltage level.

Each predefined electrical configuration may be associated with a predefined voltage level. Merely to illustrate this point, consider the following example. Suppose the signal bus <NUM> comprises two signal bus lines. A first electrical configuration that may be asserted on the signal bus lines may include asserting <NUM>. 5V on one line and 3V on the other line. This configuration may be associated with a voltage level say, for example, 10V. A second electrical configuration might be to short the first and second signal bus lines, and this configuration may be associated with a voltage level of, say, 15V, and so on.

If the circuit <NUM> requires 10V, then the configuration circuitry <NUM> may assert the first electrical configuration on the signal bus <NUM>. Likewise, if the circuit <NUM> requires 15V, then the configuration circuitry <NUM> may assert the second electrical configuration on the signal bus <NUM>, and so on. In accordance with principles of the present disclosure, the circuit <NUM> may specify to the external device <NUM> what voltage level to output when the external device can support multiple outputs by asserting a suitable electrical configuration on the signal bus lines that the external device may detect. These voltage levels, of course, are merely to illustrate an example; specific voltage levels will depend on implementation, adherence to industry specs. , and so on.

In some embodiments, the electrical configuration asserted on the signal bus <NUM> may be detected by the external device <NUM> at block 210a, and in response, the external device may reconfigure itself to output a voltage level that corresponds to the detected electrical configuration. At block <NUM>, the circuit <NUM> may receive a voltage from the external device <NUM> at the specified voltage level. For example, the circuit <NUM> may use the received voltage to charge a battery (e.g., <NUM>, <FIG>) or to provide power to a load (e.g., <NUM>, <FIG>).

A specific embodiment according to principles of the present disclosure may be incorporated in the Universal Serial Bus (USB) interface (e.g., USB Specification, Revision <NUM>) as depicted in <FIG>. More particularly, the embodiment depicted in <FIG> may include an embodiment of circuit <NUM> that is based on the USB Battery Charging Specification, Revision <NUM> (BC1. A large majority of devices conform to BC1. <NUM>, and so this embodiment may have desirable benefits from in terms of manufacturing and installed user base. Accordingly, in some embodiments, circuit <NUM> may operate in conformance with BC1. <NUM>, thus providing for devices that are compatible with existing devices, are easy to manufacture (since most of the circuitry has already been designed), and offer benefits of the present disclosure.

A portable device <NUM> may attach to an external device <NUM>. The portable device <NUM> may be any electronic device that incorporates a USB interface; e.g., mobile communication device, digital camera, computer tablet, etc. Likewise, the external device <NUM> may be any electronic device that incorporates a USB interface and can provide power to the portable device <NUM>, including power supplies, battery chargers, other electronic devices such as a computer, and so on.

A cable (e.g., cable <NUM>, <FIG>) that mechanically and electrically connects the portable device <NUM> and the external device <NUM> may comprise four wires including a power line called VBUS, signal bus lines D+ and D-, and a ground line. These four wires are found in standard USB A and USB B plugs (e.g., connectors <NUM> and <NUM>, <FIG>). Accordingly, VBUS constitutes an example of power bus <NUM> and <NUM> shown in <FIG>. The D+ and D- lines represent an example of signal lines comprising signal bus <NUM> and <NUM> shown in <FIG>.

In some embodiments, the portable device <NUM> may include a comparator to compare a voltage asserted on VBUS with a voltage level VOTG_SESSN_VLD. The comparator may be used to determine that an attachment to external device <NUM> has been made; e.g., when the voltage level on VBUS exceeds VOTG_SESSN_VLD.

The portable device <NUM> may include detection circuitry 312a, 312b, which produce respective signals DCH_DET and CHG_DET. As explained above in connection with the detection circuitry <NUM> shown in <FIG>, the detection circuitry 312a, 312b in <FIG> may detect different electrical configurations on the D+ and D- lines, as will be described in more detail below.

Configuration circuitry 322a may include voltage sources VDP_SRC, VDP_UP & resistor RDP_UP, VLGC_HI & current source IDP_SRC, and IDP_SINK, and their respective switches for selective connection to the D+ line. Additional configuration circuitry 322b may also include VDM_UP, VDM_SRC, RDM_DWN, and IDM_SINK, and their respective switches for selective connection to the D- line. As explained above in connection with the configuration circuitry <NUM> shown in <FIG>, the configuration circuitry 322a, 322b in <FIG> may assert different electrical configurations on the D+ and D- lines, as will be described in more detail below.

In accordance with the present disclosure, the external device <NUM> may include a power supply <NUM> having an output voltage with selectable voltage levels. For example, the selectable voltage levels may be 5V, 9V, 12V, and 20V. Of course, fewer or more levels may be provided, different levels may be output, and so on. The external device <NUM> may further include comparators 324a, 324b, 324c, and 324d for detecting voltage levels and current flows (e.g., through resistors RDAT_LKG and RDM_DWN) on the D+ and D- lines. The voltage levels and current flows define different electrical configurations that can be asserted on the D+ and D- lines by the portable device <NUM>. The reference levels shown in <FIG> use <NUM> V voltage levels, but it will be appreciated that in other embodiments, the reference levels may be at other voltage levels.

As will be explained below, the external device <NUM> may also assert different electrical configurations on the D+ and D- lines using the resistors RDAT_LKG and RDM_DWN. In some embodiments, a glitch filter <NUM> may be provided to avoid false positive detections due to noise on the D+ line.

An illustrative example of an external device <NUM> (<FIG>) is the power supply <NUM> (e.g., wall adapter), shown in <FIG>, that can provide 9V, 12V, and 20V voltage levels, in addition to the 5V that is conventionally provided on VBUS. A transformer may be used to electrically isolate the high-power primary side <NUM> from the low-power secondary side <NUM>, which interfaces with the external environment. The secondary side <NUM> may include an interface IC having connections for the D+ and D- lines. The interface IC may include detection circuitry such as comparators 324a-324d shown in <FIG>, for example. In some embodiments, the interface IC may be integrated into the AC/DC control IC. A primary side <NUM> may provide a selectable output voltage level on VBUS. For example, the primary side <NUM> may include a power section <NUM> that is coupled to the secondary side <NUM>. In the particular example shown in <FIG>, an optical coupling <NUM> comprising a transmitting LED on the side of the secondary side <NUM> may transmit optical signals to a receiving LED on the side of the power section <NUM> to control the output of the power section.

The interface IC may include circuitry and logic (not shown) that can detect and decode a particular electrical configuration asserted on the D+ and D- lines. The 9V, 12V, and 20V switches may be activated to control, via a resistor network 402a, the optical signal that is produced by the transmitting LED; e.g., by controlling the frequency of the optical signal. The optical signal may then be received by the receiving LED and sensed a controller in the power section <NUM>. The controller may generate a voltage on VBUS having a voltage level based on the optical signal sensed by the receiving LED. It will be appreciated, of course, that the use of resistor network 402a and optical LEDs is simply illustrative and that in other embodiments, the secondary side <NUM> may communicate with the primary side <NUM> using any known signaling technique other than optical signaling; e.g., a digital signal may be sent from the secondary side to the primary side.

It will be appreciated that the external device <NUM> need not be a power supply per se, but may be any electronic device that is configured to provide multiple output voltage levels. For example, in some embodiments, the external device <NUM> may be a laptop computer that incorporates voltage selector <NUM> and includes a power source having selectable output voltage levels.

<FIG> illustrates processing in accordance with the present disclosure, when the portable device <NUM> (<FIG>) attaches to an external device. As explained above, in some embodiments, the portable device <NUM> may operate in accordance with BC1. <NUM> in which the portable device <NUM> is viewed as attaching to a port on the external device. Going forward, the terms "external device" and "port" may be used concurrently and/or interchangeably. Typical values for voltage levels mentioned below may be set in accordance with BC1. <FIG>, for example, shows a table of voltage values set forth in BC1.

At loop <NUM>, the portable device <NUM> may detect an attachment event. For example, an external device may output a voltage on VBUS. In accordance with BC1. <NUM>, if the portable device <NUM> detects a voltage level on VBUS > VOTG_SESSN VLD for a predetermined period of time, the portable device <NUM> may determine that an attachment to the external device has occurred.

At block <NUM>, the portable device <NUM> may determine whether the external device is a dedicated charging port (DCP) or not. At block <NUM>, if a DCP is detected, processing continues at block <NUM>; otherwise, a standard downstream port (SDP) or a charging downstream port (CDP) has been detected. The DCP, SDP, and CDP are port types defined in BC1.

In accordance with BC1. <NUM>, block <NUM> may include a primary detection step and a secondary detection step. The portable device <NUM> may perform primary detection to detect if the external device is an SDP by asserting an electrical configuration (i.e., a voltage level) on the D+ line and sensing an electrical configuration (i.e., a voltage level) asserted on the D- line. If an SDP is detected, then the NO branch of block <NUM> is taken and the portable device <NUM> may proceed in accordance with detection of a SDP. If the external device is determined not to be an SDP, then the portable device <NUM> may perform secondary detection to detect whether the external device is a DCP or a CDP by asserting an electrical configuration on the D- line and sensing an electrical configuration on the D+ line. If a CDP is detected, then the NO branch of block <NUM> is taken and the portable device <NUM> may proceed in accordance with detection of a CDP.

If a CDP is not detected, then in some embodiments, processing proceeds to block <NUM>. In other embodiments, before proceeding to block <NUM>, the portable device <NUM> may perform additional detection steps in block <NUM> to detect for attached devices that may be proprietary, may conform to other standards, or are otherwise non-compliant with BC1. <NUM>; e.g., Apple® power adapters typically do not conform to BC1. <NUM>, laptop manufacturers may produce power adapters that use proprietary circuitry, and so on. If a non-BC1. <NUM> port is not detected, then processing may proceed to block <NUM>.

Continuing with <FIG>, if processing reaches block <NUM>, the portable device <NUM> has determined that it is attached to a DCP. An external device in accordance with the present disclosure (e.g., <NUM>, <FIG>) appears electrically like a DCP at this point; i.e., the external device shorts together the D+ and D- lines using, for example, a switch connected between the D+ and D- lines as shown in <FIG>. A conventional DCP is typically specified to output 5V. By comparison, an external device according to the present disclosure may output any one of several higher voltage levels (e.g., 9V, 12V, 20V, etc.), in addition to a 5V level. Accordingly, an external device in accordance with the present disclosure may be referred to as a high voltage DCP (HVDCP). In accordance with principles of the present disclosure, the portable device <NUM> may perform an additional detection to distinguish between an external device that is a conventional DCP and an HVDCP. Thus, in some embodiments, the portable device <NUM> may assert a voltage level VDP_SRC on the D+ line, at block <NUM>.

If the external device is a conventional DCP, the short between D+ and D- will be maintained. Accordingly, at block <NUM>, the portable device <NUM> will sense that the voltage level asserted at D- is >VDAT_REF and detect that a conventional DCP is attached.

If the external device is an HVDCP (e.g., <NUM>, <FIG>), then, in accordance with the present disclosure, the HVDCP will respond to the D+ line being asserted at VDP_SRC by opening the short between the D+ and D- line. Accordingly, at block <NUM>, the portable device <NUM> will sense a voltage level asserted at D- that is ≤ VDAT_REF, which may indicate that an HVDCP is attached. At block <NUM>, if the portable device <NUM> continues to detect a voltage on VBUS, that may serve to indicate to the portable device that the external device is still attached and that the external device is an HVDCP.

At this point, the portable device <NUM> may select an operating voltage to receive from the HVDCP. If 5V operation is desired at block <NUM>, the portable device <NUM> may assert the following electrical configuration on the D+ and D- lines at block 514a: VDP_SRC on D+ and ground potential on D-. Similarly, if 9V operation is desired at block <NUM>, the portable device may assert the following electrical configuration on the D+ and D- lines at block 516a: VDP_UP on D+ and VDM_SRC on D-. If 12V operation is desired at block <NUM>, the portable device may assert the following electrical configuration on the D+ and D- lines at block 518a: VDP_SRC on D+ and VDM_SRC on D-. If 20V operation is desired at block <NUM>, the portable device may assert the following electrical configuration on the D+ and D- lines at block 516a: VDP UP on D+ and VDMUP on D-.

It can be appreciated, of course, that any suitable combination of voltage levels may be associated with the different operating voltages. It can be further appreciated that in some embodiments, different current flows can be asserted on the D+ and D-lines instead of asserting voltage levels. More generally, combinations of different voltage levels and current flows may be asserted on the D+ and D- lines.

Continuing with <FIG>, in some embodiments, if at block <NUM> a voltage level is still present on VBUS, processing may loop back to block <NUM>. The loop allows the portable device <NUM> to dynamically change the operating voltage as needed, providing a high degree of flexibility of operation in the portable device <NUM>. Thus, for example, at a time t<NUM>, the portable device <NUM> may assert a first electrical configuration on the D+ and D- lines to receive a first voltage level on VBUS. At a subsequent time t<NUM> (without having to re-attach) the HVDCP, the portable device <NUM> may assert a second electrical configuration on the D+ and D- lines to receive a second voltage level on VBUS.

Referring now to <FIG>, processing in an external device (e.g., <NUM>, <FIG>) in accordance with the present disclosure, namely an HVDCP, will now be discussed. At block <NUM>, the HVDCP may initialize itself for detection as a DCP. For example, the HVDCP may assert 5V on VBUS and short the D+ and D- lines. In addition, the D+ line is pulled down using resistor RDAT_LKG (about <NUM> KΩ) per BC1. In this state, the HVDCP appears electrically to be a DCP. The HVDCP enters a loop <NUM> until the D+ line exceeds VDATREF.

When the HVDCP is attached to the portable device <NUM>, the portable device will proceed through its detection sequence as described above. If the portable device <NUM> can accept different output voltage levels on VBUS, the portable device can indicate this fact to the HVDCP by asserting VDP_SRC on the D+ line (block <NUM>, <FIG>), which the HVDCP will detect at blocks <NUM> and <NUM>.

At blocks <NUM> and <NUM>, a timer (not shown) in the HVDCP may be initiated while the HVDCP is sensing the D+ line using the glitch filter <NUM> (<FIG>). The glitch filter <NUM> may provide a measure of safety by avoiding a false positive indication that the portable device <NUM> accept different voltage levels. At block <NUM>, if the D+ line remains >VDAT_REF after the timeout, this may indicate to the HVDCP that the portable device <NUM> can receive different operating voltage levels and is looking for an HVDCP. Accordingly, at block <NUM>, the HVDCP may open the short between the D+ and D- lines and pull down the D- line through resistor RDM_DWN to indicate to the portable device <NUM> that it is attached to an HVDCP.

At block <NUM>, if the HVDCP senses an electrical configuration where the D-line is >VDAT_REF, then at block 614a the HVDCP will output 5V on VBUS. At block <NUM>, if the HVDCP senses an electrical configuration where the D+ line is >VDAT_REF, then at block 616a the HVDCP will output 12V on VBUS. Similarly, at block <NUM>, if the HVDCP senses an electrical configuration where the D- line is >VSEL_REF, then at block 618a the HVDCP will output 20V on VBUS. Otherwise, at block <NUM> the HVDCP will output 9V on VBUS. In some embodiments, VSEL_REF may be set to 2V ± <NUM>.

Processing continues to block <NUM> to check that the D+ line continues to be >VDAT_REF. If so, processing loops back to block <NUM>, allowing the HVDCP to change its output voltage to a different level.

The foregoing processing between the portable device <NUM> and the HVDCP may be summarized in the flow chart shown in <FIG>. At <NUM>, an HVDCP is attached to the portable device. The HVDCP is initially configured to appear as a DCP by outputting 5V on VBUS and shorting its D+ and D- lines. At <NUM>, the portable device performs detection according to BC1. At <NUM>, the portable device detects a DCP, thus marking completion of the detection process per BC1. The portable device then asserts VDP_SRC on the D+ line, in accordance with principles of the present disclosure, to see if the attached DCP is an HVDCP. At <NUM>, the HVDCP senses the D+ line to look for VDP_SRC, which indicates the portable device is capable of receiving multiple voltage levels. At <NUM>, the HVDCP opens the short between D+ and D- and turns on RDM_DWN to signify to the portable device that an HVDCP is attached. At <NUM>, the portable device asserts an electrical configuration on D+ and D- corresponding to a desired voltage level. At <NUM>, the HVDCP outputs the desired voltage level.

An advantageous aspect of the present disclosure is that backward compatibility with existing devices is maintained. For example, a portable device in accordance with the principles of the present disclosure will recognize and operate with an HVDCP, according to the processing outlined in <FIG> and <FIG> above. Moreover, a portable device in accordance with the principles of the present disclosure will recognize and operate with non-HVDCP devices, such as an SDP, CDP, DCP, and in some embodiments, non-BC1. <NUM> ports (e.g., Apple® power adapters) per blocks <NUM>, <NUM>, and <NUM> in <FIG>. From the HVDCP side, an HVDCP will operate with a portable device of the present disclosure in accordance with the processing outlined in <FIG> and <FIG> above. Moreover, an HVDCP will operate with a conventional portable device by virtue of the loop <NUM>-<NUM> in <FIG>. Since a conventional portable device will not assert VDP_SRC on the D+ signal line after DCP detection, processing in the HVDCP will take the NO branch from block <NUM>.

Claim 1:
An electronic circuit (<NUM>) in a portable device comprising:
a power bus (<NUM>) connectable to an external device (<NUM>);
a signal bus (<NUM>) connectable to the external device; and
characterized in further comprising
circuitry (<NUM>, <NUM>, <NUM>) connected to the signal bus and configured to apply thereto an electrical configuration from among a plurality of electrical configurations in response to sense a predetermined electrical configuration on the signal bus, each of the electrical configurations associated with a voltage level,
wherein the electrical configuration applied to the signal bus lines of the signal bus is analog in nature and is a voltage level, including ground potential, applied to one or more signal bus lines, or multiple voltage levels each applied to another one of several signal bus lines, or one or more currents flowing respectively in one or more signal bus lines, or connecting one or more of the signal bus lines to a resistor or a capacitor or a inductor, or connecting together one or more of the signal bus lines, or a combination of voltage, current flows, and/or resistor or capacitor or inductor,
wherein the power bus is configured to receive a voltage from the external device at a voltage level that is substantially equal to the voltage level associated with the electrical configuration applied to the signal bus by the circuitry after the electrical configuration is applied to the signal bus by the circuitry.