System and method for reducing power loss in switched-capacitor power converters

Patent metadata

Field	Value
Publication number	US-2016352218-A1
Application number	US-201515116780-A
Country	US
Kind code	A1
Filing date	Feb 4, 2015
Priority date	Feb 4, 2014
Publication date	Dec 1, 2016
Grant date	—

Abstract

A system for reducing power loss in a switched-capacitor converter includes a first and second switched capacitor sub-converter each having a flying capacitor and a first, second, third, and fourth switching device. Each switching device is controlled by one of a first, second, third, and fourth clock signal. The first, second, third and fourth clock signals of the second switched capacitor sub-converter are inverted such that the first switched capacitor sub-converter operates during a first phase and the second switched capacitor converter operates during a second phase that is 1800 degrees out of phase from the first phase. The system also includes a resonant charge sharing portion for coupling a bottom-plate parasitic capacitance of the first switched capacitor sub-converter to a bottom-plate parasitic capacitance of the second switched capacitor converter.

First claim

What is claimed is:

1 . A system for reducing power loss in a switched-capacitor converter, the system comprising:
a first and second switched capacitor sub-converter each having
a first, second, third, and fourth switching device each controlled by one of a first, second, third, and fourth clock signal, and
a flying capacitor,
wherein the first, second, third and fourth clock signals of the second switched capacitor sub-converter are inverted such that the first switched capacitor sub-converter operates during a first phase and the second switched capacitor converter operates during a second phase that is 180 degrees out of phase from the first phase; and,
a resonant charge sharing portion for coupling a bottom-plate parasitic capacitance of the first switched capacitor sub-converter to a bottom-plate parasitic capacitance of the second switched capacitor converter.

2 . The system of claim 1 , the resonant charge sharing portion comprising a sharing inductor coupled in series with a sharing switch.

3 . The system of claim 2 , wherein
a capacitance value of the bottom-plate parasitic capacitance is the same for each of the first and second switched capacitor sub-converters, and the sharing switch is in an on mode for a length of time defined by π√{square root over (L s C bp /2)} where L s is an inductance of the sharing inductor and C bp is the bottom-plate parasitic capacitance of at least one of the first and second switched capacitor sub-converters.

4 . The system of claim 2 , wherein
a capacitance value of the bottom-plate parasitic capacitance is not equal for each of the first and second switched capacitors, and the sharing switch is in an on mode for a length of time is defined by

π


L
s



C

b



p



1

*

C

b



p



2

C

b



p



1

+

C

b



p



2

,

where L s is the inductance of the sharing inductor, C bp1 is the bottom-plate parasitic capacitance value of the first switched capacitor sub-converter, and C bp2 is the bottom-plate parasitic capacitance value of the second switched capacitor sub-converter.

5 . The system of claim 1 , the first and second switched capacitor converters being resonant such that a resonant inductor is coupled in series with the flying capacitor.

6 . The system of claim 1 , wherein, within each first and second switched capacitor converters, the first switching device is electrically coupled between an input node and a first flying node, the second switching device is electrically coupled between the first flying node and an output node, the third switching device is electrically coupled between the output node and a second flying node, and the fourth switching device is electrically coupled between the second flying node and ground.

7 . The system of claim 6 , wherein, within each of the first and second switched capacitor converters, the flying capacitor is electrically coupled between each of the first and second flying nodes, and a bottom-plate parasitic capacitance is between the second flying node and ground.

8 . The system of claim 7 , wherein, within each of the first and second switched capacitor converters, a resonant inductor is coupled in series with the flying capacitor between first flying node and the flying capacitor.

9 . The system of claim 7 , wherein, within each of the first and second switched capacitor converters, a resonant inductor is coupled between the second flying node and the flying capacitor.

10 . The system of claim 9 , wherein the resonant charge sharing portion comprises a sharing switch, controlled via a fifth clock signal, coupled to the second flying node, within each of the first and second switched capacitor converters.

11 . The system of claim 10 , wherein the sharing switch is in an on state, as determined by the fifth clock signal, for a length of time defined by

π


(

L

x



1

+

L

x



2

Assignees

• Dartmouth College

Inventors

• Stauth Jason T
• Kesarwani Kapil

Classifications

• H02M1/08

  Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters · CPC title

• H02M2001/0058

  Electricity · mapped topic

• H02M3/07 Primary

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

• H02M3/072

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

• H02M1/0058

  by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero (using an auxiliary actively switched resonant commutation circuit connected to an intermediate DC voltage or between two push-pull branches of an inverter bridge H02M7/4811; in resonant inverters H02M7/4815; in inverters operating from a resonant DC source H02M7/4826) · CPC title