System and Method for Rapidly Charging a USB Device

• US 20080042616A1
• Filed: 08/17/2006
• Published: 02/21/2008
• Est. Priority Date: 08/17/2006
• Status: Active Grant

• Current Assignee: Microchip Technology Incorporated
• Original Assignee: Standard Microsystems Corporation (Microchip Technology Incorporated)
• Inventors: Monks, Morgan H., Bohm, Mark R.
• Granted Patent: US 7,631,111 B2
• Time in Patent Office: Days
• US Class Current: 320/106
• CPC Class Codes: H02J 7/0036 using connection detecting circuits H02J7/0034 takes precedence
• CPC Class Codes: H04L 12/10 Current supply arrangements

Abstract

System and method for enumerating and/or enumerating a device. The device may be a USB portable device which adheres to a first standard, e.g., the USB specification, and may engage in enumeration with respect to a USB hub/USB host device. Where a battery included in the device is sufficiently low, the device may engage in low power enumeration, e.g., to begin charging the device using enumerated power. Low power enumeration may allow the device to enumerate even when the device is incapable of powering on. Additionally, or alternatively, the device may determine whether the hub/host device is capable of providing high power charging. If it is, the device may begin charging the battery of the device using power provided by the hub/host device at a high power level.

Claims

1. A method for charging a device, comprising:

detecting coupling of the device, wherein the device comprises a battery, wherein the device conforms to a first standard, and wherein the first standard specifies provision of maximum power to the device at a first power level;

determining if the device should receive high-power charging of the battery;

providing power to the device at a second power level to charge the battery if the device should receive high-power charging of the battery, wherein the second power level is greater than the first power level.

2. The method of claim 1, wherein the device comprises a universal serial bus (USB) device.

3. The method of claim 1, wherein the first standard comprises the USB specification.

4. The method of claim 1, wherein said detecting, said determining, and said providing are performed by a USB hub.

5. The method of claim 1, further comprising:

providing power to the device at the first power level to charge the battery if the device should not receive high-power charging of the battery.

6. The method of claim 1, further comprising:

if the USB should not receive high-power charging, enumerating the USB device.

7. The method of claim 1, wherein, prior to and during charging, the USB device is not enumerated.

8. The method of claim 1, wherein said determining if the USB device requires high-power charging comprises detecting a specified voltage or current from the USB device.

9. The method of claim 1, wherein the first power level comprises a current of 500 milliamps (mA).

10. The method of claim 1, wherein said providing power to the USB device comprises sending a signal to the USB device indicating that the USB device is coupled to a USB charging device.

11. The method of claim 1, where said determining if the USB device should receive high-power charging comprises determining if the battery of the USB device is substantially out of power.

12. A USB hub, comprising:

one or more downstream ports, operable to couple respectively to one or more downstream USB devices;

logic circuitry coupled to the one or more downstream ports; and

relay circuitry coupled to the logic circuitry, wherein the relay circuitry is configured to relay power from a power source coupled to the USB hub;

wherein the logic circuitry is operable to;

detect coupling of a USB device to a downstream port of the one or more downstream ports, wherein the USB device comprises a battery, wherein the device conforms to a first standard, and wherein the first standard specifies provision of maximum power to the device at a first power level; and

determine if the USB device should receive high-power charging of the battery; and

wherein the relay circuitry is operable to provide power to the USB device at a second power level to charge the battery if the logic circuitry determines that the USB device should receive high-power charging of the battery, wherein the second power level is greater than the first power level, and wherein, prior to and during charging, the USB device is not enumerated.

13. The USB hub of claim 12, wherein the USB hub is actively powered.

14. The USB hub of claim 12, wherein the logic circuitry is further operable to:

enumerate the USB device if the USB device does not require high-power charging.

15. The method of claim 12, wherein the relay circuitry is further operable to:

provide power to the device at the first power level to charge the battery if the device should not receive high-power charging of the battery.

16. The USB hub of claim 12, wherein the logic circuitry is further operable to send a signal to the USB device indicating that the USB device is coupled to a USB charging device.

17. A first USB device, comprising:

a battery;

at least one port, coupled to the battery, wherein the at least one port is operable to couple to a second USB device which is operable to charge the battery; and

logic circuitry, coupled to the battery and the at least one port;

wherein the first USB device conforms to a first standard, and wherein the first standard specifies provision of maximum power to the first USB device at a first power level; and

wherein the logic circuitry is operable to;

detect coupling of the second USB device to the at least one port;

determine if the first USB device should receive high-power charging of the battery; and

request and receive power at a second power level to charge the battery from the second USB device if the first USB device should receive high-power charging, wherein the second power level is greater than the first power level.

18. The first USB device of claim 17, wherein the first USB device is not enumerated during charging.

19. The first USB device of claim 17, wherein the logic circuitry is further operable to:

determine if the first USB device requires enumerated power charging of the battery;

enable enumeration of the first USB device if the USB device requires enumerated power charging of the battery; and

receive enumerated power to charge the battery from the second USB device, wherein the enumerated power is equal power at the first power level.

20. The first USB device of claim 19, wherein the at least one port comprises low-power enumeration circuitry, and wherein the low-power enumeration circuitry is operable to engage in enumeration of the first USB device using power received from the second USB device.

22. The first USB device of claim 17, wherein the first USB device further comprises device circuitry, operable to perform functions of the device and engage in enumeration of the first USB device when the battery is sufficiently charged.

23. The first USB device of claim 22, wherein the at least one port comprises low-power enumeration circuitry, wherein the low-power enumeration circuitry is operable to:

engage in enumeration of the first USB device using power supplied by the second USB device prior to enumeration if the battery is not sufficiently charged for the device circuitry to enumerate the first USB device.

24. A method for charging a USB device, comprising:

detecting coupling of a USB device, wherein the USB device comprises a battery;

charging the battery of the USB device at high power if the USB device requires high-power charging, wherein the high power is in excess of power that would be provided to an enumerated USB device, and wherein, prior to and during said charging, the USB device is not enumerated.