High voltage dedicated charging port

[0001] This disclosure claims priority to US Application No. 13/956,574 filed August 1, 2013 and is a continuation-in-part of US Application No. 13/759,865 filed February 5, 2013 , which also claims priority to US Provisional Application No. 61/719,822 filed October 29, 2012, each are incorporated herein in their entirety by reference for all purposes.

BACKGROUND

[0002] Unless otherwise stated herein, the approaches described in this section are not prior art to the claims of this application and are not admitted to be prior art by inclusion in this subsection.

[0003] Power requirements for modern electronic devices are increasing very rapidly; for example, devices with larger screens, LTE devices (radios, modems, etc.), multi-core processors, etc. To maintain acceptable operating times, these devices use larger capacity batteries. In such systems, charging times tend to be very long when conventional power sources are used. Reasons include: (1) limited power capacity (USB 5V/1.8A max); and (2) problems with peak voltage signal levels between the input power source and the battery. On the other hand, many readily available power sources (eg monitors, laptops, etc.) cannot be used due to their higher voltage operation than what the portable device can tolerate. Implementing a solution that requires the use of a secondary portable device connector significantly increases the cost of the solution and the consumer (proper connector, wall adapter, etc.).

[0004] With increasing battery capacities, the 5V input voltage does not provide sufficient voltage signal level to achieve high enough charge currents due to the impedances of the cable, connector, PCB, and charger. Many batteries now have a float voltage of 4.35V which makes this problem worse, especially as the trend is towards higher voltages. For example, a 2S battery provides approximately 8.4V or 8.7V, thus requiring a voltage greater than 5V to charge efficiently.

SYNTHESIS

[0005] A circuit for charging a battery of an external device may include a detection circuit for detecting an electrical configuration of signal lines comprising a wire for connecting the circuit to the external device. A configuration circuit can 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 reasserted electrical configuration on the signal lines.

[0006] In some embodiments, the circuit operates in accordance with the USB Battery Charging Specification. The power line can be VBUS and the signal lines can be D+ and D- as stated in the USB specification. The circuit can be backwards-compatible with industry standards, allowing for standardized connectors and cabling, while at the same time allowing a greater range of operating voltages beyond the standard 5V operating level of the USB specification.

[0007] The following detailed description and accompanying figures provide a better understanding of the nature and advantages of the present disclosure.

BRIEF DESCRIPTION OF THE FIGURES

[0008] Fig. 1 is a high level generic block diagram of circuitry in accordance with the present disclosure.

[0009] Figs. 1A and 1B show additional illustrative embodiments in accordance with the present disclosure.

[0010] Fig. 2 is a functional flowchart of high level processing in accordance with the present disclosure.

[0011] Fig. 3 shows an illustrative embodiment based on the USB specification.

[0012] Fig. 4 illustrates an example of an external device.

[0013] Fig. 5 shows a functional flowchart of the processing in the handheld device shown in Fig. 3.

[0014] Fig. 6 shows a flowchart of the processing function in the external device shown in Fig. 3.

[0015] Fig. 7 shows the voltage according to the levels of the USB Battery Charging Specification.

[0016] Fig. 8 is a summary of the operation of the system according to the present disclosure.

DETAILED DESCRIPTION

[0017] In the following description, for purposes of explanation, numerous examples and specific details are set forth in order to provide a complete understanding of the present disclosure. It will be apparent, however, to those of skill in the art that the present disclosure as expressed in the claims may include some or all of the features of these examples alone or in combination with other features described below, and may include , in addition, modifications and equivalents of the characteristics and concepts described in the present.

[0018] Fig. 1 shows a circuit 100 according to embodiments of the present disclosure. The circuit 100 can be included in a portable device 10, such as a smartphone, tablet computer, etc. Portable device 10 may include a battery 12 to power the portable device. In some embodiments, battery 12 may be a rechargeable battery that circuitry 100 can charge. Battery 12 may be a single cell configuration, or it may be a multi-cell battery.

[0019] The portable device 10 may be connected to an external device 14. In some embodiments, the external device 14 may be an alternating current (AC) adapter, such as a wall adapter. In other embodiments, external device 14 can be an electronic device that can supply power to the portable device. For example, the external device 14 may be the laptop computer that supplies power from its own battery or by virtue of being connected to an AC power supply.

[0020] Portable device 10 and external device 14 may have respective connectors 22 and 24. A cable 26 may be electrically connected to portable device 10 and external device 14.

[0021] In some embodiments, circuit 100 may include circuitry 102, detection circuitry 104, control circuitry 106, and configuration circuitry 108. Load circuitry 100 may include a power bus 114 for electrical connection to a line on cable 26. Circuit 100 may further include a signal bus 112 comprising a plurality of signal bus lines for electrical connection to signal lines on cable 26. The number of signal bus lines that comprise the signal bus 112 may vary from one embodiment to another. For example, one 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.

[0022] In some embodiments, charging circuit 102 may be connected to power bus 114 to transfer power from a voltage supplied by external device 14 to charge battery 12; for example, through a coupling 102a.

The charging circuit 102 can be of any known design, such as a switching charger design for example. In some embodiments, coupling 102a may comprise battery terminals that battery 12 may connect to. In other embodiments, charging circuit 102 may be connected to any load other than a battery. In yet other embodiments, charging circuit 102 may be connected to both a load and a battery (eg, battery 12).

[0023] Detection circuit 104 may be connected to signal bus 112 to detect various electrical configurations on the signal bus lines that comprise the signal bus. External device 14 can assert an electrical pattern on the signal lines of cable 26 that detection circuitry 104 can detect on signal bus 112. In some embodiments, detection circuitry 104 may comprise voltage comparators, current sensors, and the like, to detect an electrical configuration on signal bus 112.

[0024] An asserted electrical configuration on the signal bus lines of signal bus 112 may be one voltage level (including ground potential) that asserts one or more signal bus lines, or multiple voltage levels asserted across several signal bus lines. An electrical configuration can also be one or more currents that respectively flow in one or more of the signal bus lines. In some embodiments, an electrical configuration can 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. signal bus. In some embodiments, an electrical configuration can be asserted using a combination of voltage, current flows, and/or resistance (or other passive device).

[0025] In some embodiments, the electrical configuration restated on the signal bus lines of signal bus 112 is analog in nature. In other embodiments, the electrical configuration may be communicated through or over signal bus 112. For example, the electrical configuration may be digital in nature where the signal bus lines of signal bus 112 communicate digital information. Although the remainder of the present disclosure will primarily describe electrical patterns as analog signals, those of skill in the art will appreciate that the electrical pattern can be asserted or detected in a variety of ways on signal bus 112.

[0026] As mentioned above, an electrical configuration can be asserted on the signal bus lines of signal bus 112 by an external device 14 electrically connected to the signal bus via cable 26. Similarly, an electrical configuration it can be asserted on the signal bus lines by configuration circuitry 108. In some embodiments, for example, the configuration circuitry 108 may include voltage sources, current sources, switches (eg, MOS switches), passive devices (eg, a resistor), and the like, to assert some combination of levels. of voltage and/or current levels on one or more of the signal bus lines that comprise the signal bus 112.

[0027] Control circuit 106 may be wired to receive one or more signals 104a from sense circuit 104. Signals 104a may be indicative of a detected electrical configuration asserted on signal bus 112 by external device 14. The Control circuit 106 may be connected to provide one or more control signals 106a to configuration circuits 108 in order to assert a particular electrical configuration on signal bus 112.

[0028] Portable device 10 may further comprise electronics (charging) 101. For example, if portable device 10 is a tablet computer, electronics 101 may comprise components such as a processor, memory, display, etc. Electronic devices 101 may be connected to power bus 114 through connector 114a to draw power received by circuit 100.

[0029] The external device 14 may include a voltage selector 122 and a power section 124, in addition to other electronic circuitry (not shown) that comprise the external device. For example, the external device 14 may be a laptop computer, or the external device may be a power source (eg, an AC adapter), etc. Power circuit 124 may provide a voltage at one of several selectable voltage levels that may be delivered to portable device 10 via cable 26. For example, external device 14 may include a power bus 134 that is connected to the power line on the cable 26. The voltage selector 122 can connect the voltage produced by the power section 124 to the power bus 134. In some embodiments, voltage selector 122 may be connected to signal bus 132 comprising a plurality of signal bus lines, which may be electrically connected to signal bus 112 via cable 26. As will be explained in more detail below, voltage selector 122 can detect or sense an electrical configuration on signal bus 132 and control or otherwise signal power section 124 to output a voltage level that corresponds to the detected electrical configuration. Voltage selector 122 may comprise digital logic, analog circuitry, or a combination of digital and analog components to sense or sense the electrical configuration on signal bus 132.

[0030] Those of skill in the art will appreciate that embodiments in accordance with the present disclosure include any electronic device. In more general embodiments, portable device 10 can be any electronic device and circuit 100 can omit charging circuit 102. Referring to Fig. 1A, for example, an electronic device 10' may comprise circuitry 100' in accordance with the present disclosure that does not necessarily include circuitry for charging a battery. For example, the electronic device 10' may not use a battery or otherwise provide a rechargeable battery, and therefore may omit battery charging circuitry. As in Fig. 1, the electronic devices 101 in the electronic device 10' can be powered by a voltage on the power bus 114.

[0031] As another example, Fig. 1B shows an embodiment where an electronic device 10 can provide the voltage that is received on power bus 114 to another electronic device 10a; for example, using a connection 116. In some embodiments, the electronic component 101 may be an electrical connection between the power bus 114 and the connection 116. In other embodiments, electronic component 101 may include electronics for electronic device 10 that is powered by power bus 114.

[0032] Fig. 2 illustrates an operation of circuit 100 in conjunction with an external device in accordance with the principles of the present disclosure. At block 202, circuit 100 may detect a coupling to an external device (eg, 14, Fig. 1). For example, circuitry 100 may include circuitry (not shown) to detect the presence of a voltage on power bus 114 that is provided by external device 14.

[0033] At block 204, circuit 100 can determine what type of external device is connected to the circuit. For example, external device 14 may be a conventional power source that supplies a single output voltage. In accordance with the present disclosure, the circuit may be linked to an external device that is capable of supplying a voltage at any of several selectable voltage levels.

[0034] In some embodiments, external device 14 may assert an electrical pattern on signal bus 132 to indicate what type of device it is. Just to illustrate, assume that signal bus 132 is made up of two signal bus lines. An electrical configuration on the two signal bus lines can be asserted by external device 14 (for example, using voltage selector 122) 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 could involve the application of two different DC voltage levels on each of the signal bus lines, etc.

[0035] The detection circuit 104 can detect the particular electrical configuration, asserted by the external device by detecting the signal bus lines comprising the signal bus 112. On the basis of the electrical configuration detected by the detection circuit detection 104, signals 104a may be provided to control circuitry 106 to indicate the type of external device connected to circuit 100. In accordance with the present disclosure, if at block 206, the electrical configuration detected at block 204 indicates that external device 14 is of a first kind (eg, has selectable voltage levels) then further processing can be performed, as described below. If the external device 14 is not of the first class, then the circuit 100 can operate under the assumption that it is attached to an external device that is capable of outputting a single voltage level, and at block 208 it receives the voltage from the external device. Consequently, at block 208, the voltage received by circuit 100 can then be used to charge a battery (eg, 26, Fig. 1) or provide power to a load (eg, 101).

[0036] If, at block 206, it is determined that the external device 14 is of the first class where the external device supports multiple selectable output voltage levels, then, in accordance with the principles of the present disclosure, the circuit 100 at block 212 may use configuration circuitry 108 to assert an electrical configuration on signal bus 112 among several predefined electrical configurations. In some embodiments, for example, circuit 100 can support different types of battery 12, which have different voltage levels for proper battery charging. For example, some batteries can be charged with 5 volts, other batteries may require 9 volts, 12 volts, 20 volts, etc. Similarly, different types of loads 101 can operate at different voltage levels. Accordingly, control circuitry 106 can generate signals 106a to operate configuration circuitry 108 to assert an electrical configuration on signal bus 112 that corresponds to a specified voltage level.

[0037] Each predefined electrical configuration may be associated with a predefined voltage level. Just to illustrate this point, consider the following example. Assume that the signal bus 112 is made up of two signal bus lines. A first electrical configuration that can be asserted on the signal bus lines may include asserting 1.5V on one line and 3V on the other line. This setting can be associated with a voltage level, that is, for example, 10V. A second electrical configuration could be to short the first and second signal bus lines, and this configuration can be associated with a voltage level of eg 15V etc.

[0038] If circuit 100 requires 10V, then configuration circuit 108 can assert the first electrical configuration on signal bus 112. Similarly, if circuit 100 requires 15V, then configuration circuit 108 can assert the second electrical configuration on the signal bus 112, etc. In accordance with the principles of the present disclosure, circuit 100 may specify to external device 14 what voltage level to output at when the external device can support multiple outputs by asserting a suitable electrical configuration on the signal bus lines that the device external can detect. These voltage levels, of course, are merely to illustrate an example; specific voltage levels will depend on the application, compliance with industry specifications, etc.

[0039] In some embodiments, the asserted electrical configuration in bus signal 112 may be detected by external device 14 at block 210a, and in response, the external device may reconfigure itself to output a voltage level which corresponds to the electrical configuration detected. At block 212, circuit 100 may receive a voltage from external device 14 at the specified voltage level. For example, circuit 100 may use the received voltage to charge a battery (eg, 26, Fig. 1) or to provide power to a load (eg, 101, Fig. 1).

[0040] A specific embodiment in accordance with the principles of the present disclosure may be incorporated into the Universal Serial Bus (USB) interface (eg, the USB specification, Revision 2.0) as depicted in Fig. 3. More particularly, the embodiment depicted in Fig. 3 may include an embodiment of circuit 100 that is based on the USB Battery Charging Specification, Revision

1.2 (BC1.2). A large majority of products are BC1.2 compliant, and so this realization can have desirable benefits in terms of manufacturing and installed user base. Accordingly, in some embodiments, circuit 100 can operate in accordance with BC1.2, thus providing devices that are compatible with existing devices, easy to manufacture (since most circuitry has already been designed), and offer benefits of this disclosure.

[0041] A portable device 302 can be attached to an external device 304. The portable device 302 can be any electronic device that incorporates a USB interface; e.g. mobile communication device, digital camera, tablet computer, etc. Similarly, external device 304 can be any electronic device that incorporates a USB interface and can provide power to portable device 302, including power supplies, battery chargers, other electronic devices such as a computer, etc.

[0042] A cable (for example, cable 26, Fig. 1) that mechanically and electrically connects the portable device 302 and the external device 304 may comprise four cables including a power line called VBUS, D+ signal bus lines, and D-, and a ground line. These four cables are found in standard USB A and USB B plugs (for example connectors 22 and 24, Fig. 1). Accordingly, VBUS constitutes an example of the power bus 114 and 134 shown in Fig. 1. Lines D+ and D- represent an example of signal lines comprising signal bus 112 and 132 shown in Fig. 1.

[0043] In some embodiments, portable device 302 may include a comparator for comparing an asserted voltage on VBUS with a VOTG_SESSN_VLD voltage level. The comparator may be used to determine that a link to an external device 304 has been made; for example, when the voltage level on VBUS exceeds VOTG_SESSN_VLD.

[0044] The portable device 302 may include detection circuits 312a, 312b, which produce respective signals DCH_DET and CHG_DET. As explained above in connection with the detection circuit 104 shown in Fig. 1, the detection circuit 312a, 312b in Fig. 3 can detect different electrical configurations on the D+ and D- lines, as will be described in more detail below.

[0045] The configuration circuits 322a can include voltage sources VDP_SRC, VDP_UP and resistors RDP_UP, VLGC_HI and current sources IDP_SRC and IDP_SINK, and their respective switches for selective connection to the D+ line. Additional configuration circuits 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 circuit 108 shown in Fig. 1, the configuration circuit 322a, 322b in Fig. 3 can assert different electrical configurations on the D+ and D- lines, as will be described in more detail below.

[0046] In accordance with the present disclosure, external device 304 may include a power source 314 having an output voltage with selectable voltage levels. For example, the selectable voltage levels can be 5V, 9V, 12V, and 20V. Of course, fewer or more levels may be provided, different levels may be output, and so on. External device 304 may further include comparators 324a, 324b, 324c, and 324d for sensing voltage levels and current flows (eg, 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 302. The reference levels shown in Fig. 3 they use 1V voltage levels, but it will be appreciated that in other embodiments, the reference levels may be at other voltage levels.

[0047] As will be explained below, the external device 304 can also assert different electrical configurations on the D+ and D- lines using the resistors RDAT_LKG and RDM_DWN. In some embodiments, a miss filter 334 may be provided to prevent false positive detections due to noise on the D+ line.

[0048] An illustrative example of an external device 304 (Fig. 3) is the power source 400 (eg, wall adapter), shown in Fig. 4, which can provide 9V, 12V, and 20V voltage levels. , in addition to the 5V that is conventionally provided on VBUS. A transformer can be used to electrically isolate the high power primary side 404 from the low power secondary side 402, which interacts with the external environment. The secondary side 402 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. 3, for example. In some embodiments, the interface IC may be integrated into AC/DC control ICs. A primary side 404 may provide a selectable output voltage level on VBUS. For example, the primary side 404 may include a power section 412 that couples to the secondary side 402. In the particular example shown in Fig. 4, an optical coupling 414 comprising an LED on the secondary side 402 side may transmitting optical signals to an LED receiver on the power section side 412 to control the output of the power section.

[0049] The interface IC may include circuitry and logic (not shown) that can detect and decode a particular electrical configuration, restated on the D+ and D- lines. The 9V, 12V, and 20V switches can be activated to control, through a network of resistors 402a, the optical signal that is produced by the LED transmission; for example, by controlling the frequency of the optical signal. The optical signal can then be received by the LED receiver and sensed by a driver in power section 412. The driver can generate a voltage on VBUS having a voltage level based on the optical signal detected by the LED receiver. It will of course be appreciated that the use of the network of resistors 402a and optical LEDs is merely illustrative and that in other embodiments, the secondary side 402 may communicate with the primary side 404 using any known signaling technique other than optical signaling; for example, a digital signal can be sent from the secondary side to the primary side.

[0050] It will be appreciated that external device 304 need not be a power source per se, but can be any electronic device that is configured to provide multiple output voltage levels. For example, in some embodiments, external device 304 may be a laptop computer that incorporates a voltage selector 402 and includes a power supply that has selectable output voltage levels.

[0051] Fig. 5 illustrates processing in accordance with the present disclosure, when portable device 302 (Fig. 3) is connected to an external device. As explained above, in some embodiments, the portable device 302 may operate in accordance with BC1.2 where the portable device 302 is viewed as attaching to a port on the external device. Hereinafter, the terms external device and port can be used concurrently and/or interchangeably. The typical values ​​of the voltage levels mentioned below can be established according to BC1.2. Fig. 7, for example, shows a table of voltage values ​​set to BC1.2.

[0052] In loop 502, portable device 302 may detect a pairing event. For example, an external device can output a voltage on VBUS. According to BC1.2, if the portable device 302 detects a voltage level on VBUS > VOTG_SESSN_VLD for a predetermined period of time, the portable device

302 can determine that a link to the external device has occurred.

[0053] At block 504, the portable device 302 can determine whether the external device is a dedicated charging port (DCP) or not. At block 506, if a DCP is detected, processing continues at block 508; otherwise, a standard downstream port (SDP) or a charging downstream (CDP) port has been detected. DCP, SDP, and CDP are port types defined in BC1.2.

[0054] According to BC1.2, block 504 may include a primary detection stage and a secondary detection stage. The portable device 302 can perform primary detection to detect whether the external device is an SDP by asserting an electrical configuration (i.e., a voltage level) on the D+ line and detecting an electrical configuration (i.e., a voltage level). voltage) reaffirmed on the D- line. If an SDP is detected, then the NO branch of block 506 is taken and the portable device 302 may proceed in accordance with the detection of an SDP. If the external device is determined not to be an SDP, then the portable device 302 can 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 detecting an electrical configuration on the D+ line. If a CDP is detected, then the NO branch of block 506 is taken and the portable device 302 may proceed in accordance with the detection of a CDP.

[0055] If a CDP is not detected, then in some embodiments, processing proceeds to block 508. In other embodiments, before proceeding to block 508, portable device 302 may perform additional detection steps in block 504 to detect connected devices that may be suitable, may conform to other standards, or otherwise not. agree with BC1.2; for example, Apple® power adapters typically do not conform to BC1.2, laptop manufacturers may produce power adapters that use proprietary circuitry, etc. If a non-BC1.2 port is not detected, then processing may proceed to block 508.

[0056] Continuing with Fig. 5, if the processing reaches block 508, it has been determined that the portable device 302 binds a DCP. An external device in accordance with the present disclosure (eg, 304, Fig. 3) appears electrically as a DCP at this point; that is, the external device is shorted together with the D+ and D- lines, using, for example, a switch connected between the D+ and D- lines, as shown in Fig. 3. A conventional DCP is typically specified at 5V output. By comparison, an external device in accordance with the present disclosure can output any of several higher voltage levels (eg, 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 the principles of the present disclosure, the portable device 302 may perform additional detection to distinguish between an external device that is a conventional DCP and an HVDCP. Therefore, in some embodiments, portable device 302 may assert a VDP_SRC voltage level on the D+ line, at block 508.

[0057] If the external device is a conventional DCP, the short between D+ and D- will be maintained. Accordingly, at block 510, the portable device 302 will sense that the asserted voltage level at D- is > VDAT_REF and will detect that a conventional DCP is attached.

[0058] If the external device is an HVDCP (eg, 304, Fig. 3), then according to the present disclosure, the HVDCP will respond to the D+ line asserting itself in VDP_SRC by opening the short between the D line + and D-. Accordingly, at block 510, the portable device 302 will detect a D-asserted voltage level that is < VDAT_REF, which may indicate that an HVDCP is engaged. At block 512, if the portable device 302 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.

[0059] At this point, the portable device 302 can select an operating voltage to receive from the HVDCP. If 5V operation is desired at block 514, portable device 302 can assert the following electrical configuration on the D+ and D- lines at block 514a: VDP_SRC at D+ and at ground potential D-. Similarly, if 9V operation is desired at block 516, 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 518, 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 516, the portable device can assert the following electrical configuration on the D+ and D- lines at block 516a: VDP_UP on D+ and VDM_UP on D-.

[0060] It can of course be appreciated 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 may be asserted on the D+ and D- lines instead of asserting voltage levels. More generally, combinations of different voltage levels and current flows can restate on the D+ and D- lines.

[0061] Continuing with Fig. 5, in some embodiments, if at block 522 a voltage level is still present on VBUS, processing may return to block 514. The loop allows portable device 302 to dynamically change the voltage of operation as needed, providing a high degree of operating flexibility in the portable device 302. Thus, for example, at a time t1, the portable device 302 can assert a first electrical configuration on the D+ and D- lines to receive a first voltage level on VBUS. At a later time t2 (without having to reconnect) the HVDCP, the portable device 302 can assert a second electrical configuration on the D+ and D- lines to receive a second voltage level on VBUS.

[0062] Referring now to Fig. 6, processing in an external device (eg, 304, Fig. 3), in accordance with the present disclosure, ie, an HVDCP, will be discussed. At block 602, the HVDCP may be independently initialized for detection as a DCP. For example, the HVDCP can assert 5V on VBUS and short the D+ and D- lines. Also, the D+ line is stepped down using resistor RDAT_LKG (about 500 KOhms) by BC1.2. In this state, the HVDCP electrically appears to be a DCP. The HVDCP goes into a 604 loop until the D+ line exceeds VDAT_REF.

[0063] When the HVDCP is attached to the portable device 302, the portable device will proceed through its detection sequence as described above. If the portable device 302 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 508, Fig. 5), which the HVDCP will detect in blocks 606 and 608.

[0064] In blocks 606 and 608, a timer (not shown) in the HVDCP may be started while the HVDCP is detecting the D+ line using fault filter 334 (Fig. 3). Fault filter 334 may provide a safety measure by preventing a false positive indication that portable device 302 accepts different voltage levels. At block 610, if the D+ line remains >VDAT_REF after the timeout, this may indicate to the HVDCP that the portable device 302 can receive different operating voltage levels and is searching for an HVDCP. Consequently, at block 612, the HVDCP may short the D+ and D- lines and short the D- line through the RDM_DWN resistor to indicate to the portable device 302 that it is coupled to an HVDCP.

[0065] At block 614, if the HVDCP detects an electrical configuration where the D- line is > VDAT_REF, then at block 614a the HVDCP will output 5V on VBUS. At block 616, if the HVDCP detects an electrical configuration where the D+ line is > VDAT_REF, then at block 616A the HVDCP will output 12V on VBUS. Similarly, at block 618, if the HVDCP detects an electrical configuration where the D- line is > VSEL_REF, then at block 618a the HVDCP will output 20V on VBUS. Otherwise, at block 620 the HVDCP will output 9V on VBUS. In some embodiments, VSEL_REF may be set to 2V ± 0.2V.

[0066] Processing continues at block 622 to check that the D+ line is still >VDAT_REF. If so, processing returns to block 614, allowing the HVDCP to change its output voltage to a different level.

[0067] The above process between the portable device 302 and the HVDCP can be summarized in the flowchart shown in Fig. 8. At 802, an HVDCP is coupled 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 804, the portable device performs detection in accordance with BC1.2. At 806, the portable device detects a DCP, thus marking the completion of the detection process by BC1.2. The portable device then asserts VDP_SRC on the D+ line, in accordance with the principles of the present disclosure, to see if the coupling DCP is an HVDCP. At 808, the HVDCP senses the D+ line looking for VDP_SRC, indicating that the portable device is capable of receiving multiple voltage levels. At 810, the HVDCP opens the short between D+ and D- and turns RDM_DWN on to signify the portable device that an HVDCP is attached. At 812, the portable device asserts an electrical configuration on the D+ and D- lines corresponding to a desired voltage level. At 814, the HVDCP outputs the desired voltage level.

[0068] 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, in accordance with the processing described in Figs. 5 and 6 above. On the other hand, 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-BC1.2 ports (for example, adapters power Apple®) according to blocks 502, 504, and 506 in Fig. 5. From the HVDCP side, an HVDCP will operate a portable device of the present disclosure according to the processing described in Figs. 5 and 6 above. On the other hand, an HVDCP will operate with a conventional portable device by virtue of the 602-604 loop in Fig. 6. Since a conventional portable device will not assert VDP_SRC on the +D signal line after DCP detection, the process in the HVDCP it will take the NO branch of block 604.

[0069] The above description illustrates various embodiments of the present invention along with examples of how aspects of the particular embodiments may be implemented. The above examples are not to be considered as the only embodiments, and are presented to illustrate the flexibility and advantages of particular embodiments as defined by the following claims. Based on the foregoing description and the following claims, other arrangements, embodiments, implementations, and equivalents may be employed without departing from the scope of the present disclosure defined by the claims.

[0070] The following is claimed: