Adaptive USB charging method and system

• US 8,892,912 B2
• Filed: 05/03/2011
• Issued: 11/18/2014
• Est. Priority Date: 02/11/2011
• Status: Active Grant

• Current Assignee: VIA Labs Incorporated (VIA Technologies)
• Original Assignee: VIA Technologies Incorporated (VIA Technologies)
• Inventors: Lai, Yi-Lin, Huang, Bo-Ming, Wu, Kuo-Yu
• Primary Examiner(s): Yanchus, III, Paul
• Assistant Examiner(s): Chang, Eric
• Application Number:
  US13/100,110
• Publication Number:
  US 20120210146A1
• Time in Patent Office: 1,295 Days
• Field of Search: 713/300
• US Class Current: 713/300
• CPC Class Codes: G06F 1/263 Arrangements for using multiple switchable power supplies, e.g. battery and AC G06F1/30 takes precedence
• CPC Class Codes: G06F 1/266 Arrangements to supply power to external peripherals either directly from the computer or under computer control, e.g. supply of power through the communication port, computer controlled power-strips
• CPC Class Codes: G06F 1/3212 Monitoring battery levels, e.g. power saving mode being initiated when battery voltage goes below a certain level

Abstract

An adaptive universal serial bus (USB) charging method and system are disclosed. In a low-power state, a USB device is charged with a non-USB charging mode. The non-USB charging mode is retained when no variation of a data signal coupled to the USB device is detected. When the data signal possesses variation for a first period, it is switched to a third proprietary charging mode.

Claims

1. An adaptive Universal Serial Bus (USB) charging method, comprising:

charging a USB device according to a non-USB charging mode in a low-power state;

retaining the non-USB charging mode when no variation on a data signal coupled to the USB device is detected;

switching to a third proprietary charging mode when variation on the data signal for a first period is detected; and

keeping track of a second period and then switching to the non-USB charging mode in the third proprietary charging mode;

wherein the data signal is from a positive data input pin and a negative data input pin of the USB device.

2. The method of claim 1, further comprising:

directly switching to the non-USB charging mode when removal of the USB device is detected in the third proprietary charging mode.

3. The method of claim 2, further comprising:

detecting a voltage level of the data signal, according to which a pull-high resistor or a pull-low resistor is controllably coupled to the data signal; and

detecting state transition on the data signal to determine the removal of the USB device.

4. The method of claim 1, further comprising:

setting a register to switch the non-USB charging mode to a first proprietary charging mode or a second proprietary charging mode, and then subjecting the USB device to charging, wherein a charging current of the first proprietary charging mode is different from a charging current of the second proprietary charging mode.

5. The method of claim 1, further comprising:

keeping track of a third period after switching to the non-USB charging mode, and continuously detecting the variation on the data signal for the first period when the third period is equal to a predetermined period.

6. The method of claim 4, wherein the first proprietary charging mode and the second proprietary charging mode are a first current charging mode and a second current charging mode, respectively, defined in APPLE USB Power Adaptor, and the third proprietary charging mode is a dedicated charging port (DCP) charging mode defined in Battery Charging Specification.

7. The method of claim 1, wherein the variation on the data signal is detected by:

comparing a positive data signal and a first reference signal, thereby generating a first comparison result;

comparing a negative data signal and a second reference signal, thereby generating a second comparison result; and

converting the first comparison result and the second comparison result to two digital logic values, and determining the variation on the data signal according to state transition on one of the two digital logic values;

wherein the data signals include the positive data signal and the negative data signal.

8. The method of claim 1, further comprising:

when going back to a normal-power state from the low-power state, switching to a predetermined charging mode, and disconnecting a USB power for a period and then reconnecting the USB power, followed by entering the normal-power state, wherein the USB device performs USB data transfer and USB charging at the same time in the predetermined charging mode.

9. The method of claim 8, wherein the low-power state is a state S3, S4 or S5 defined in Advanced Configuration and Power Interface (ACPI), wherein the state S3 indicates a standby state, the state S4 indicates a hibernation state, and the state S5 indicates a soft off state;

wherein the normal-power state is a state S0 defined in ACPI to indicate a working state.

10. The method of claim 1, further comprising:

charging the USB device according to a charging downstream port (CDP) charging mode when the USB device is detected to support the CDP charging mode in a normal-power state;

retaining the CDP charging mode and a USB power when entering the low-power state from the normal-power state; and

switching to a predetermined charging mode when entering the normal-power state from the low-power state.

11. The method of claim 1, further comprising:

determining whether the USB device supports a high speed or a speed higher than the high speed, when the USB device is detected not to support a charging downstream port (CDP) charging mode in a normal-power state;

charging the USB device according to a standard downstream port (SDP) charging mode if the USB device is determined not to support the high speed or the speed higher than the high speed;

retaining the SDP charging mode and a USB power when entering the low-power state from the normal-power state; and

switching to a predetermined charging mode when entering the normal-power state from the low-power state.

12. The method of claim 1, further comprising:

determining whether the USB device supports a high speed or a speed higher than the high speed, when the USB device is detected not to support a charging downstream port (CDP) charging mode in a normal-power state;

charging the USB device according to a standard downstream port (SDP) charging mode if the USB device is determined to support the high speed or the speed higher than the high speed; and

when entering the low-power state from the normal-power state, switching to the non-USB charging mode, and disconnecting a USB power for a period and then reconnecting the USB power, followed by entering the low-power state.

13. An adaptive Universal Serial Bus (USB) charging system, comprising:

a controller configured to charge a USB device according to a non-USB charging mode in a low-power state; and

a detect unit configured to detect variation on a data signal coupled to the USB device;

wherein the controller retains the non-USB charging mode when the detect unit detects no variation on the data signal coupled to the USB device;

the controller controls a switch to switch to a third proprietary charging mode when the detect unit detects variation on the data signal for a first period;

wherein the data signal is from a positive data input pin and a negative data input pin of the USB device, and wherein the controller controls the switch to switch to the non-USB charging mode when a second period elapses.

14. The system of claim 13, wherein the controller directly switches to the non-USB charging mode when the detect unit detects removal of the USB device in the third proprietary charging mode.

15. The system of claim 14, further comprising:

a control circuit configured to controllably couple a pull-high resistor or a pull-low resistor to the data signal according to a voltage level of the data signal detected by the detect unit;

wherein the detect unit detects state transition on the data signal to determine the removal of the USB device.

16. The system of claim 13, wherein the controller sets a register to switch the non-USB charging mode to a first proprietary charging mode or a second proprietary charging mode, and accordingly charges the USB device, wherein a charging current of the first proprietary charging mode is different from a charging current of the second proprietary charging mode.

17. The system of claim 13, wherein the controller keeps track of a third period after switching to the non-USB charging mode, and continuously detects the variation on the data signal for the first period when the third period is equal to a predetermined period.

18. The system of claim 16, wherein the first proprietary charging mode and the second proprietary charging mode are a first current charging mode and a second current charging mode, respectively, defined in APPLE USB Power Adaptor, and the third proprietary charging mode is a dedicated charging port (DCP) charging mode defined in Battery Charging Specification.

19. The system of claim 13, wherein the detect unit comprises:

a first comparator configured to compare a positive data signal and a first reference signal, thereby generating a first comparison result;

a second comparator configured to compare a negative data signal and a second reference signal, thereby generating a second comparison result; and

a logic conversion unit configured to convert the first comparison result and the second comparison result to two digital logic values, and determine the variation on the data signal according to the two digital logic values;

wherein the data signals include the positive data signal and the negative data signal.

20. The system of claim 13, further comprising:

when going back to a normal-power state from the low-power state, switching to a predetermined charging mode by the switch, and disconnecting a USB power for a period and then reconnecting the USB power, followed by entering the normal-power state, wherein the USB device performs USB data transfer and USB charging at the same time in the predetermined charging mode.

21. The system of claim 20, wherein the low-power state is a state S3, S4 or S5 defined in Advanced Configuration and Power Interface (ACPI), wherein the state S3 indicates a standby state, the state S4 indicates a hibernation state, and the state S5 indicates a soft off state;

wherein the normal-power state is a state S0 defined in ACPI to indicate a working state.

22. The system of claim 13, further comprising:

a charging downstream port (CDP) detect unit configured to detect a CDP charging mode, wherein the USB device is charged according to the CDP charging mode when the USB device is detected to support the CDP charging mode in a normal-power state;

wherein the CDP charging mode and a USB power are retained when entering the low-power state from the normal-power state; and

switching to a predetermined charging mode when entering the normal-power state from the low-power state.

23. The system of claim 13, further comprising:

a charging downstream port (CDP) detect unit configured to detect a CDP charging mode, wherein the USB device is determined whether to support a high speed or a speed higher than the high speed, when the USB device is detected not to support a charging downstream port (CDP) charging mode in a normal-power state;

the USB device is charged according to a standard downstream port (SDP) charging mode if the USB device is determined not to support the high speed or the speed higher than the high speed;

wherein the SDP charging mode and a USB power are retained when entering the low-power state from the normal-power state; and

switching to a predetermined charging mode when entering the normal-power state from the low-power state.

24. The system of claim 13, further comprising:

a charging downstream port (CDP) detect unit configured to detect a CDP charging mode, wherein the USB device is determined whether to support a high speed or a speed higher than the high speed, when the USB device is detected not to support a charging downstream port (CDP) charging mode in a normal-power state;

the USB device is charged according to a standard downstream port (SDP) charging mode if the USB device is determined to support the high speed or the speed higher than the high speed;

wherein the switch is controlled to switch to the non-USB charging mode, and disconnect a USB power for a period and then reconnect the USB power, followed by entering the low-power state, when entering the low-power state from the normal-power state.