High efficiency DC-DC converter

Patent metadata

Field	Value
Publication number	US-9362818-B2
Application number	US-201113013986-A
Country	US
Kind code	B2
Filing date	Jan 26, 2011
Priority date	Feb 19, 2010
Publication date	Jun 7, 2016
Grant date	Jun 7, 2016

Abstract

A charge pump includes an input, an output, and a fixed voltage node; a first capacitor and at least a second capacitor; and a plurality of switches adapted to selectively couple the first capacitor and the at least the second capacitor to the input, the output, and the fixed voltage node. A switch controller is adapted to switch the plurality of switches in response to at least three phase signals to provide fixed gains. A phase generator is adapted to generate the at least three phase signals, wherein at least one of the at least three phase signals has a duty cycle that is different from at least one other of the at least three phase signals. The phase generator is also adapted to adjust the frequency of a clock signal used to generate the at least three phase signals so that a minimum switching frequency is provided.

First claim

What is claimed is:

1. A charge pump comprising:
an input, an output, and a fixed voltage node;
a first flying capacitor and a second flying capacitor, each having a first terminal and a second terminal;
a plurality of switches configured to selectively couple the first terminal and the second terminal of the first flying capacitor and the second flying capacitor to the input, the output, and the fixed voltage node, the plurality of switches consisting of eleven switches;
a switch controller configured to open and close select ones of the plurality of switches in response to a first phase signal, a second phase signal, and a third phase signal in order to provide at the output a set of fixed gains of a voltage at the input comprising ¼ and ¾; and
a phase generator configured to generate the first phase signal, the second phase signal, and the third phase signal, wherein a duty cycle of one of the first phase signal, the second phase signal, and the third phase signal is different from a duty cycle of one other of the first phase signal, the second phase signal, and the third phase signal.

2. The charge pump of claim 1 , wherein each duty cycle of the first phase signal and the third phase signal is approximately 25%, and the duty cycle of the second phase signal is approximately 50%.

3. The charge pump of claim 1 , wherein the phase generator introduces a fixed delay interval between a falling edge of the first phase signal and a rising edge of the second phase signal such that the first phase signal and the second phase signal are non-overlapped.

4. The charge pump of claim 1 , wherein the phase generator introduces a fixed delay interval between a falling edge of the second phase signal and a rising edge of the third phase signal such that the second phase signal and the third phase signal are non-overlapped.

5. The charge pump of claim 1 , wherein the phase generator uses a clock signal having a given frequency to generate the first phase signal, the second phase signal, and the third phase signal, each having half the given frequency of the clock signal.

6. The charge pump of claim 1 , wherein the first flying capacitor and the second flying capacitor each have a value of capacitance of approximately 220 nF.

7. The charge pump of claim 1 , wherein the phase generator is configured to automatically adjust a frequency of a clock signal in response to varying voltage conditions at the input and/or the output of the charge pump.

8. The charge pump of claim 7 , wherein the phase generator automatically increases the frequency of the clock signal to extend operation of the charge pump when a voltage headroom between a target voltage and an output voltage at the output begins to non-linearly decrease.

9. The charge pump of claim 8 , wherein the target voltage is provided by a low dropout regulator coupled to the output of the charge pump.

10. The charge pump of claim 1 wherein the only capacitors in the charge pump are the first flying capacitor, the second flying capacitor, and an output capacitor.

11. A charge pump comprising:
an input, an output, and a fixed voltage node;
a first flying capacitor and a second flying capacitor, each having a first terminal and a second terminal;
a plurality of switches configured to selectively couple the first terminal and the second terminal of the first flying capacitor and the second flying capacitor to the input, the output, and the fixed voltage node, the plurality of switches comprising:
a first switch coupled between the input and the first terminal of the first flying capacitor;
a second switch coupled between the first terminal of the first flying capacitor and the output;
a third switch coupled between ground and the second terminal of the first flying capacitor;
a fourth switch coupled between the second terminal of the second flying capacitor and the output;
a fifth switch coupled between the second terminal of the first flying capacitor and the first terminal of the second flying capacitor;
a sixth switch coupled between the input and the first terminal of the second flying capacitor;
a seventh switch coupled between the first terminal of the second flying capacitor and the output;
an eighth switch coupled between ground and the second terminal of the second flying capacitor;
a ninth switch coupled between the second terminal of the second flying capacitor and the output;
a tenth switch coupled between the first terminal of the first flying capacitor and the first terminal of the second flying capacitor; and
an eleventh switch coupled between the input and the second terminal of the second flying capacitor;

a switch controller configured to open and close select ones of the plurality of switches in response to a first phase signal, a second phase signal, and a third phase signal in order to provide at the output a set of fixed gains of a voltage at the input comprising ¼, ⅓, ½, ⅔, and ¾; and
a phase generator configured to generate the first phase signal, the second phase signal, and the third phase signal, wherein a duty cycle of one of the first phase signal, the second phase signal, and the third phase signal is different from a duty cycle of one other of the first phase signal, the second phase signal, and the third phase signal.

12. The charge pump of claim 11 wherein the only capacitors in the charge pump are the first flying capacitor, the second flying capacitor, and an output capacitor.

13. The charge pump of claim 12 wherein the output capacitor is coupled between the output and ground.

14. A mobile terminal comprising:
a power amplifier (PA) for amplifying signals to be transmitted from the mobile terminal;
a receiver to receive signals to be processed by the mobile terminal; and
a charge pump configured to supply power to the PA, the charge pump comprising:
an input, an output, and a fixed voltage node;
a first flying capacitor and a second flying capacitor, each having a first terminal and a second terminal;
a plurality of switches configured to selectively couple the first terminal and the second terminal of the first flying capacitor and the second flying capacitor to the input, the output, and the fixed voltage node, the plurality of switches consisting of eleven switches;
a switch controller configured to open and close select ones of the plurality of switches in response to a first phase signal, a second phase signal, and a third phase signal in order to provide at the output a set of fixed gains of a voltage at the input comprising ¼ and ¾; and
a phase generator configured to generate the first phase signal, the second phase signal, and the third phase signal, wherein the duty cycle of one of the first phase signal, the second phase signal, and the third phase signal is different from the duty cycle of one other of the first phase signal, the second phase signal, and the third phase signal.

15. The mobile terminal of claim 14 , wherein the set of fixed gains comprises ¼, ⅓, ½, ⅔, and ¾.

16. The charge pump of claim 14 , wherein each duty cycle of the first phase signal and the third phase signal is approximately 25%, and the duty cycle of the second phase signal is approximately 50%.

17. The mobile terminal of claim 14 , wherein the phase generator introduces a fixed delay interval between a falling edge of the first phase signal and a rising edge of the second phase signal such that the first phase signal and the second phase signal are non-overlapped.

18. The mobile terminal of claim 14 , wherein the phase generator introduces a fixed delay interval betwe

Assignees

• Gorisse Philippe
• Khlat Nadim
• Rf Micro Devices Inc

Inventors

• Gorisse Philippe
• Khlat Nadim

Classifications

• H02M3/07 Primary

  using capacitors charged and discharged alternately by semiconductor devices with control electrode {, e.g. charge pumps} · CPC title

• H02M2003/072

  Electricity · mapped topic

• H02M3/072

  adapted to generate an output voltage whose value is lower than the input voltage · CPC title