Power Supply with Fast Discharging for Configurable Output Voltage

• US 20150340890A1
• Filed: 05/21/2014
• Published: 11/26/2015
• Est. Priority Date: 05/21/2014
• Status: Active Grant

• Current Assignee: Dialog Semiconductor Incorporated (Renesas Electronics Corporation)
• Original Assignee: Dialog Semiconductor Incorporated (Renesas Electronics Corporation)
• Inventors: Chen, Yimin, Li, Yong, Zheng, Junjie, Wong, Dickson T., Yao, Jianming
• Granted Patent: US 10,063,073 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/00308 Overvoltage protection
• CPC Class Codes: H02J 7/0042 characterised by the mechanical construction
• CPC Class Codes: H02M 1/322 Means for rapidly discharging a capacitor of the converter for protecting electrical components or for preventing electrical shock
• CPC Class Codes: H02M 3/33523 with galvanic isolation between input and output of both the power stage and the feedback loop

Abstract

A universal serial bus (USB) charger provides power to a client device. A USB connector interfaces with a client device and receives a request for the output voltage of the USB charger to be at a specific value. If the requested voltage level is lower than the current output voltage level, the output voltage level is set to the requested level and a bleeder circuit is enabled to discharge the output capacitor of the USB charger.

Claims

1. A universal serial bus (USB) charger for providing power to a client device comprising:

a USB connector configured to interface with the client device, and to receive a request for an output voltage at a first voltage level;

a converter circuit, an output of the converter circuit coupled to the USB connector, the converter circuit configured to convert an input voltage level to an output voltage level, the converter circuit comprising an output capacitor;

a bleeder circuit coupled to the converter circuit, the bleeder circuit configured to discharge the output capacitor of the converter circuit responsive to the output voltage level of the converter circuit being greater than the first voltage level; and

an output controller configured to control the output voltage level of the converter circuit, and configured the turn the bleeder circuit on and off.

2. The USB charger of claim 1, wherein the bleeder comprises:

a first switch coupled to the output controller; and

a bleeder resistor coupled to the output capacitor and the first switch, the bleeder resistor configured to discharge the output capacitor when the first switch is closed.

3. The USB charger of claim 2, wherein the output controller is configured to turn on the first switch responsive to determining that the output voltage level of the USB charger is at a second voltage level, the second voltage level higher than the first voltage level.

4. The USB charger of claim 3, wherein the output controller is further configured to turn off the first switch responsive to determining that the output voltage level of the USB charger is within a threshold level of the first voltage level.

5. The USB charger of claim 2, wherein the bleeder further comprises:

a bleeder capacitor, the bleeder capacitor coupled in parallel to the bleeder resistor, the bleeder capacitor configured to receive a portion of charge stored in the output capacitor when the first switch is closed.

6. The USB charger of claim 2, wherein the bleeder further comprises:

a second switch coupled to the output controller; and

a bleeder capacitor coupled to the output capacitor and the second switch, the bleeder capacitor configured to receive a portion of the charge stored in the output capacitor when the second switch is closed.

7. The USB charger of claim 6, wherein the output controller is further configured to:

turn on the first switch and the second switch responsive to determining that the output voltage level of the USB charger is at a second voltage level, the second voltage level higher than the first voltage level; and

turn off the first switch responsive to determining that the output voltage of the USB charger is within a threshold level of the first voltage level.

8. The USB charger of claim 2, wherein the bleeder further comprises:

a second switch coupled to the output controller; and

a second bleeder resistor coupled to the output capacitor and the second switch, the second bleeder resistor having a resistance higher than the bleeder resistor, the second bleeder resistor configured to provide a slow discharge of the output capacitor when the first switch is opened.

9. The USB charger of claim 8, wherein the output controller is further configured to:

turn on the first switch and the second switch responsive to determining that the output voltage level of the USB charger is at a second voltage level, the second voltage level higher than the first voltage level;

turn off the first switch responsive to determining that the output voltage level of the USB charger is at a third voltage level, the third voltage level higher than the first voltage level and lower than the second voltage level; and

turn off the second switch responsive to determining that the output voltage level of the USB charger is within a threshold level of the first voltage level.

10. The USB charger of claim 8, wherein the output controller is further configured to:

turn on the first switch and the second switch responsive to determining that the output voltage level of the USB charger is at a second voltage level, the second voltage level higher than the first voltage level; and

turn off the first switch and the second switch responsive to determining that the first switch and the second switch have been on for a set amount of time.

11. A method for providing power to a client device in a plurality of voltage levels comprising:

receiving a request, at a universal serial bus (USB) charger via a USB port, for an output voltage at a first voltage level; and

responsive to determining that the requested first voltage level is lower than an output voltage level of the USB charger;

setting the output voltage level to the first level, and

enabling a bleeder circuit, the bleeder circuit configured to discharge an output capacitor of the USB charger.

12. The method of claim 11, wherein the bleeder comprises:

a first switch; and

a bleeder resistor coupled the output capacitor the first switch, the bleeder resistor configured to discharge the output capacitor when the first switch is closed.

13. The method of claim 11, wherein enabling the bleeder circuit comprises:

closing the first switch responsive to determining that the output voltage level of the USB charger is at a second voltage level, the second voltage level higher than the first voltage level.

14. The method of claim 13, further comprising:

opening the first switch responsive to determining that the output voltage level of the USB charger is within a threshold level of the first voltage level.

15. The method of claim 12, wherein the bleeder further comprises:

a bleeder capacitor, the bleeder capacitor coupled in parallel to the bleeder resistor, the bleeder capacitor configured to receive a portion of charge stored in the output capacitor when the first switch is closed.

16. The method of claim 12, wherein the bleeder further comprises:

a second switch; and

a bleeder capacitor coupled to the output capacitor and the second switch, the bleeder capacitor configured to receive a portion of the charge stored in the output capacitor when the second switch is closed.

17. The method of claim 16, further comprising:

closing the first switch and the second switch responsive to determining that the output voltage level of the USB charger is at a second voltage level, the second voltage level higher than the first voltage level; and

opening the first switch responsive to determining that the output voltage of the USB charger is within a threshold level of the first voltage level.

18. The method of claim 11, further comprising:

responsive to determining that the requested first voltage is higher than the output voltage level setting the output voltage level to the first level.

19. A method for providing power to a client device in a plurality of voltage levels comprising:

determining, by a universal serial bus (USB) charger, whether the client device is connected to the USB charger; and

responsive to determining that the client device is not connected;

determining whether an output voltage is at a second voltage level, the second voltage level higher than a first voltage level; and

responsive to determining that the output voltage level is at the second voltage level;

setting the output voltage level to the first voltage level; and

enabling a bleeder circuit, the bleeder circuit configured to discharge an output capacitor of the USB charger.

20. The method of claim 19, wherein the bleeder comprises:

a first switch; and

a bleeder resistor coupled the output capacitor the first switch, the bleeder resistor configured to discharge the output capacitor when the first switch is closed.

21. The method of claim 20, wherein enabling the bleeder circuit comprises:

closing the first switch responsive to determining that the output voltage level of the USB charger is at a second voltage level, the second voltage level higher than the first voltage level.

22. The method of claim 21, further comprising:

opening the first switch responsive to determining that the output voltage level of the USB charger is within a threshold level of the first voltage level.

23. The method of claim 20, wherein the bleeder further comprises:

a bleeder capacitor, the bleeder capacitor coupled in parallel to the bleeder resistor, the bleeder capacitor configured to receive a portion of charge stored in the output capacitor when the first switch is closed.