Power converter with capacitive energy transfer and fast dynamic response

Patent metadata

Field	Value
Publication number	US-9048727-B2
Application number	US-201414251917-A
Country	US
Kind code	B2
Filing date	Apr 14, 2014
Priority date	May 8, 2008
Publication date	Jun 2, 2015
Grant date	Jun 2, 2015

Abstract

A converter circuit and related technique for providing high power density power conversion includes a reconfigurable switched capacitor transformation stage coupled to a magnetic converter (or regulation) stage. The circuits and techniques achieve high performance over a wide input voltage range or a wide output voltage range. The converter can be used, for example, to power logic devices in portable battery operated devices.

First claim

What is claimed is:

1. A converter circuit comprising:
a switched capacitor transformation stage having a transformation stage input port and a transformation stage output port, said switched capacitor transformation stage comprising one or more switches and one or more capacitors and said switched capacitor transformation stage configured to accept an input voltage at the transformation stage input port and provide an intermediate output voltage at the transformation stage output port;
an auxiliary converter stage having an input coupled to said switched capacitor transformation stage, said auxiliary converter stage comprising one or more switches and one or more magnetic energy storage components configured to recover energy normally dissipated in capacitors of said switched capacitor transformation stage via said one or more magnetic energy storage components.

2. The converter circuit of claim 1 wherein said auxiliary converter stage operates to recover converter stage energy normally dissipated when charging capacitors of said switched capacitor transformation stage.

3. The converter circuit of claim 1 wherein the input of said auxiliary converter stage is provided having an apparent input resistance which is higher than an equivalent series resistance of said switched-capacitor transformation stage.

4. The converter circuit of claim 1 wherein said switched capacitor transformation stage operates such that a portion of a difference between the input voltage V IN and a capacitor stack voltage V C appears across the input of said auxiliary converter stage.

5. The converter circuit of claim 4 wherein said switched capacitor transformation stage operates such that the portion of the difference between the input voltage V IN and the capacitor stack voltage V C which appears across the input of the auxiliary converter stage corresponds to a majority of the difference between the input voltage V IN and the capacitor stack voltage V C which appears across the input of the auxiliary converter stage.

6. The converter circuit of claim 1 wherein in response to the one or more switches of said switched capacitor transformation stage being configured so that a capacitor in said switched capacitor transformation stage is charging or discharging, said switched capacitor transformation stage operates such that a portion of the difference between the input voltage V IN and a capacitor stack voltage V C appears across the input of said auxiliary converter stage and said auxiliary converter stage recovers energy normally dissipated when charging or discharging capacitors of said switched capacitor transformation stage.

7. The converter circuit of claim 1 wherein the portion of the difference between the input voltage V IN and the capacitor stack voltage V C corresponds to a majority of the difference between the input voltage V IN and the capacitor stack voltage V C .

8. The converter circuit of claim 1 wherein said one or more switches in said auxiliary converter stage operate at a switching frequency which is higher than the switching frequency of the one or more switches in said switched capacitor transformation stage.

9. A power converter circuit comprising:
a reconfigurable switched capacitor transformation stage having a transformation stage input port and a transformation stage output port, said transformation stage configured to accept an input voltage at the transformation stage input port and provide an intermediate output voltage at the transformation stage output port and wherein said reconfigurable switched capacitor transformation stage provides power conversion at multiple distinct conversion ratios as a function of at least one of: input voltage, a reference voltage, the intermediate voltage and an output voltage of said power converter circuit;
an auxiliary converter stage coupled to said reconfigurable switched capacitor transformation stage, said auxiliary converter stage configured to operate such that said auxiliary converter stage recovers energy normally dissipated when charging or discharging capacitors of said switched capacitor circuit.

10. The power converter circuit of claim 9 wherein:
said reconfigurable switched capacitor transformation stage comprises one or more switches and one or more capacitors; and
said auxiliary converter stage comprises one or more switches and one or more magnetic energy storage components.

11. The power converter circuit of claim 9 , wherein said reconfigurable switched capacitor transformation stage is dynamically reconfigurable to provide energy transfer at multiple, different, conversion ratios.

12. The power converter circuit of claim 9 , wherein said auxiliary converter stage recovers energy normally dissipated when charging capacitors in said switched capacitor circuit by absorbing a difference between stacked capacitor voltages in said switched capacitor circuit and a function of one or more of: an input voltage and an output voltage of the power converter circuit.

13. The power converter circuit of claim 12 wherein:
said auxiliary converter transfers energy from said switched-capacitor circuit to generate a regulated output voltage.

14. The power converter circuit of claim 10 wherein said one or more switches in said reconfigurable switched capacitor transformation stages are disposed to couple said at least one capacitor in series or in parallel with respect to the output port of said reconfigurable switched capacitor transformation stage.

15. A power converter circuit comprising:
a switched capacitor circuit having a switched-capacitor input port and a switched capacitor output port, said switched-capacitor circuit comprising one or more switches and one or more capacitors, said switched-capacitor circuit switching the one or more capacitors between at least two states to transfer energy from the switched-capacitor input port to the switched-capacitor output port, and
an auxiliary converter stage coupled to said switched capacitor circuit wherein said auxiliary converter stage switches at a frequency such that said auxiliary converter stage recovers energy normally dissipated when charging or discharging capacitors of said switched capacitor circuit.

16. The power converter circuit of claim 15 , wherein said switched capacitor circuit provides power conversion at multiple distinct conversion ratios a function of at least one of: an input voltage, a reference voltage and an intermediate voltage.

17. The power converter circuit of claim 16 , wherein said switched capacitor circuit is dynamically reconfigurable to provide energy transfer at the multiple conversion ratios.

18. The power converter circuit of claim 16 , wherein said auxiliary converter stage recovers energy normally dissipated when charging capacitors in said switched capacitor circuit by absorbing an difference between stacked capacitor voltages in said switched capacitor circuit and a function of one or more of: an input voltage and an output voltage of the power converter circuit.

19. The power converter circuit of claim 16 wherein:
said auxiliary converter stage comprises one or more switches, and one or more magnetic energy storage components, said auxiliary converter stage switching at a frequency higher than that of said switched capacitor circuit.

20. The power converter circuit of claim 19 wherein:
said auxiliary converter stage transfers energy from said switched-capacitor circuit to generate a regulated output voltage.

21. A power converter circuit havi

Assignees

• Giuliano David M
• Perreault David J
• Pilawa-Podgurski Robert C N
• Massachusetts Inst Technology

Inventors

• Giuliano David M
• Perreault David J
• Pilawa-Podgurski Robert C N

Classifications

• H02M3/07

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

• H02M3/158 Primary

  including plural semiconductor devices as final control devices for a single load · CPC title

• H02M3/155 Primary

  using semiconductor devices only · CPC title

• H02M2001/007

  Electricity · mapped topic

• H02M1/007

  Plural converter units in cascade (push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826) · CPC title