Charge pump power savings

• US 9,312,755 B2
• Filed: 03/05/2013
• Issued: 04/12/2016
• Est. Priority Date: 03/05/2013
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Wang, Le, Dhanasekaran, Vijayakumar
• Primary Examiner(s): CHENG, DIANA
• Application Number:
  US13/785,601
• Publication Number:
  US 20140253180A1
• Time in Patent Office: 1,134 Days
• Field of Search: 327108-112
• US Class Current: 1/1
• CPC Class Codes: H02M 3/07 using capacitors charged and discharged alternately by semiconductor devices with control electrode , e.g. charge pumps
• CPC Class Codes: H02M 3/071 adapted to generate a negative voltage output from a positive voltage source

Abstract

Exemplary embodiments are directed to systems, devices, methods, and computer-readable media for reducing static and dynamic power consumption of a charge pump. In one embodiment, a device may include a plurality of switches, each switch of the plurality having a gate coupled to a dedicated driver of a plurality of drivers. The device may further include at least one clamp switch coupled to at least one driver of the plurality of drivers and configured to adjust a rail voltage of the at least one driver if an input voltage is greater than a threshold voltage. In another embodiment, the device may include a plurality of multiplexers, each multiplexer of the plurality of multiplexers coupled to a portion of an associated switch of the plurality of switches and configured to disable the portion of the associated switch if a clock frequency of the charge pump is below a threshold frequency.

Claims

1. A charge pump, comprising:

a plurality of switches, each switch of the plurality having a gate coupled to a dedicated driver of a plurality of drivers; and

at least one clamp switch coupled to at least one driver of the plurality of drivers and configured to adjust at least one rail voltage of the at least one driver if an input voltage into the charge pump is greater than a threshold voltage regardless of an output voltage of the charge pump,

wherein the at least one clamp switch includes a first clamp switch coupled to a first driver of the plurality of drivers and a second clamp switch coupled to a second driver of the plurality of drivers.

2. The charge pump of claim 1, wherein

the first clamp switch is coupled to a first switch of the plurality of switches via a dedicated driver of the plurality of drivers, the first switch further coupled to an input voltage of the charge pump;

and

the second clamp switch is coupled to a second switch of the plurality of switches via a dedicated driver of the plurality of drivers, the second switch further coupled to the output voltage of the charge pump.

3. The charge pump of claim 2, the first clamp switch configured to:

cause a square wave having an upper rail voltage substantially equal to a supply voltage and a lower rail voltage substantially equal to a supply voltage minus an offset voltage to be conveyed to a gate of the first switch if the input voltage is greater than the threshold voltage; and

cause a square wave having a upper rail voltage substantially equal to the supply voltage and a lower rail voltage substantially equal to the output voltage to be conveyed to a gate of the first switch if the input voltage is not greater than the threshold voltage.

4. The charge pump of claim 2, the second clamp switch configured to:

cause a square wave having an upper rail voltage substantially equal to the output voltage plus an offset voltage and a lower rail voltage substantially equal to the output voltage to be conveyed to a gate of the first switch if the input voltage is greater than the threshold voltage; and

cause a square wave having an upper rail voltage substantially equal to a supply voltage and a lower rail voltage substantially equal to the output voltage to be conveyed to a gate of the first switch if the input voltage is not greater than the threshold voltage.

5. The charge pump of claim 1, further comprising a control module for conveying a control voltage to the at least one clamp switch.

6. The charge pump of claim 1, further comprising at least one voltage generator for generating a voltage to adjust the rail voltage of the at least one driver.

7. The charge pump of claim 1, wherein the first clamp switch is configured to adjust a lower rail voltage of the first driver if an the input voltage is greater than a the threshold voltage and the second clamp switch is configured to adjust an upper rail voltage of the second driver if an the input voltage is greater than a the threshold voltage.

8. The charge pump of claim 1, further comprising a plurality of multiplexers, each multiplexer of the plurality of multiplexers coupled to a portion of an associated switch of the plurality of switches and configured to disable the portion of the associated switch if a clock frequency of the charge pump is below a threshold frequency.

9. The method of claim 1, wherein each of the plurality of drivers is configured to output a respective waveform.

10. A charge pump, comprising:

a first plurality of switches for charging an energy storage element during a charging phase;

a second plurality of switches for conveying an output voltage via the energy storage element during an output phase;

a first clamp configured to modify a voltage applied to a first switch of the first plurality of switches if an input voltage into the charge pump is greater than a threshold voltage regardless of the output voltage of the charge pump; and

a second clamp configured to modify a voltage applied to a first switch of the second plurality of switches if the input voltage is greater than the threshold voltage.

11. The charge pump of claim 10, the first switch of the first plurality of switches coupled between the energy storage element and an input and configured to receive the input voltage at the input.

12. The charge pump of claim 10, the first switch of the second plurality of switches coupled between the energy storage element and an output and configured to convey the output voltage at the output during the output phase.

13. The charge pump of claim 10, the first clamp switch configured to cause a supply voltage to be conveyed to a gate of the first switch of the first plurality of switches during the charging phase and an output voltage to be conveyed to the gate of the first switch of the first plurality of switches during the output phase while in a power savings mode of operation.

14. The charge pump of claim 10, the first clamp switch configured to cause a supply voltage to be conveyed to a gate of the first switch of the first plurality of switches during the charging phase and a voltage substantially equal to the supply voltage minus an offset to be conveyed to the gate of the first switch of the first plurality of switches during the output phase while in a normal mode of operation.

15. The charge pump of claim 10, the second clamp switch configured to cause a supply voltage to be conveyed to a gate of the first switch of the second plurality of switches during the output phase and the output voltage to be conveyed to the gate of the first switch of the second plurality of switches during the charging phase while operating in a power savings mode of operation.

16. The charge pump of claim 10, the second clamp switch configured to cause a voltage substantially equal to the output voltage plus an offset to be conveyed to a gate of the first switch of the second plurality of switches during the output phase and the output voltage to be conveyed to the gate of the first switch of the second plurality of switches during the charging phase while in a normal mode of operation.

17. The charge pump of claim 10, further comprising a controller configured to:

compare a charge pump voltage to a first threshold voltage and a second threshold voltage, the second threshold voltage greater than the first threshold voltage;

cause the charge pump to operate in a power savings mode if the charge pump voltage is less than the first threshold; and

cause the charge pump to operate in a normal mode if the charge pump voltage is greater than the second threshold voltage.

18. The charge pump of claim 10, further comprising a control configured to disable at least a portion of at least one switch of at least one of the first plurality of switches and the second plurality of switches if a clock frequency of the charge pump is below a threshold frequency.

19. A method, comprising:

comparing a charge pump voltage of a charge pump to a threshold voltage, wherein the comparing comprises comparing the charge pump voltage to a first threshold voltage while the charge pump is in a power savings mode of operation and comparing the charge pump voltage to a second threshold voltage while the charge pump is in a normal mode of operation;

adjusting a rail voltage of at least one driver coupled to a gate of a switch of a plurality of switches of the charge pump if the charge pump voltage is greater than the second threshold voltage; and

conveying at least one signal from a controller to adjust the rail voltage of the at least one driver.

20. The method of claim 19, the adjusting a rail voltage of at least one driver comprising adjusting a rail voltage of a first driver coupled to a first switch of the plurality of switches configured to receive the charge pump voltage and adjusting a rail voltage of a second driver coupled to a second switch configured to convey an output voltage.

21. The method of claim 19, the comparing a charge pump voltage to a threshold voltage comprising comparing an input voltage of the charge pump to the threshold voltage.

22. The method of claim 19, the adjusting comprising limiting a gate-to-source voltage of the switch to substantially 3.3 volts.

23. A method, comprising:

comparing a clock frequency of a charge pump to a threshold frequency;

disabling at least a portion of one or more switches of the charge pump while enabling another portion of the one or more switches if the clock frequency is below the threshold frequency; and

conveying a control signal to a plurality of multiplexers, each multiplexer of the plurality coupled to a switch of the one or more switches to disable at least the portion of the one or more switches upon receipt of the control signal.

24. The method of claim 23, the disabling comprising disabling at least a portion of the one or more switches of the charge pump if the clock frequency is below 200 KHz.

25. A non-transitory computer-readable storage medium storing instructions that when executed by a processor cause the processor to perform instructions for operating a charge pump, the instructions comprising:

comparing a charge pump voltage of a charge pump to a threshold voltage, wherein the comparing comprises comparing the charge pump voltage to a first threshold voltage while the charge pump is in a power savings mode of operation and comparing the charge pump voltage to a second threshold voltage while the charge pump is in a normal mode of operation;

adjusting a rail voltage of at least one driver coupled to a gate of a switch of a plurality of switches of the charge pump if the charge pump voltage is greater than the second threshold voltage; and

conveying at least one signal from a controller to adjust the rail voltage of the at least one driver.

26. A non-transitory computer-readable storage medium storing instructions that when executed by a processor cause the processor to perform instructions for operating a charge pump, the instructions comprising:

comparing a clock frequency of a charge pump to a threshold frequency;

disabling at least a portion of one or more switches of the charge pump while enabling another portion of the one or more switches if the clock frequency is below the threshold frequency; and

conveying a control signal to a plurality of multiplexers, each multiplexer of the plurality coupled to a switch of the one or more switches to disable at least the portion of the one or more switches upon receipt of the control signal.

27. A device, comprising:

means for comparing a charge pump voltage of a charge pump to a threshold voltage, wherein the means for comparing is configured to compare the charge pump voltage to a first threshold voltage while the charge pump is in a power savings mode of operation and comparing the charge pump voltage to a second threshold voltage while the charge pump is in a normal mode of operation;

means for adjusting a rail voltage of at least one driver coupled to a gate of a switch of a plurality of switches of the charge pump if the charge pump voltage is greater than the second threshold voltage;

wherein the means for adjusting a rail voltage of at least one driver conveys at least one signal from a controller to adjust the rail voltage of the at least one driver.

28. A device, comprising:

means for comparing a clock frequency of a charge pump to a threshold frequency; and

means for disabling at least a portion of one or more switches of the charge pump while enabling another portion of the one or more switches if the clock frequency is below the threshold frequency, wherein the means for disabling at least a portion of one or more switches conveys a control signal to a plurality of multiplexers, each multiplexer of the plurality coupled to a switch of the one or more switches to disable the at least a portion of the one or more switches upon receipt of the control signal.