US 10,855,165 B2 · Switched capacitor converter topology using a compensation inductor for charge transfer

Abstract

Circuits and methods are provided for soft switching within a switched-capacitor DC/DC converter, so as to reduce switching losses and improve efficiency. This is accomplished, in preferred converters, by coupling a compensation inductor between one half-bridge of an output rectifier and another half-bridge of the output rectifier. The compensation inductor functions to transfer charge from or to the capacitance of switches within the converter while the switches are off, such that the voltage across each switch is reduced to zero before that switch is turned on. This provides zero-voltage switching (ZVS) and its associated high efficiency. The efficiency associated with the ZVS makes ideal zero-current switching (ZCS) less important, such that high-precision capacitors and inductors forming the resonant tanks required by near-ideal ZCS are not required. The resultant circuits are physically smaller and less expensive than other converters that require near-ideal ZCS, but achieve similar or better efficiency.

Claims20

Dependent claims

A switched-capacitor converter (SCC) comprising:

an input;
an output;
a first switch stage coupled to the input, and comprising a first switch and a second switch connected in series at a first connection node;
a first leg coupling the first connection node to a first switching node which is between the input and the output, the first leg comprising a first capacitor and a first inductor connected in series;
a second switch stage coupled to the first switch stage such that the first switch stage is coupled in series between the input and the second switch stage, the second switch stage comprising a third switch and a fourth switch connected in series at a second connection node;
a second leg coupling the second connection node to the first switching node, the second leg comprising a second capacitor and a second inductor connected in series;
and
a first compensation inductor coupled to the first leg and the second leg, the first compensation inductor configured to transfer charge to or from switch capacitances of the first switch and the second switch when the first switch and the second switch are off and to transfer charge to or from switch capacitances of the third switch and the fourth switch when the third switch and the fourth switch are off.

5 more elements

An electronic system comprising:

a circuit board;
a switched-capacitor converter (SCC) comprising:
an input;
an output having an output voltage;
a rectifier coupled to the output and configured to rectify the output voltage;
a first switch stage coupled to the input, and comprising a first switch and a second switch connected in series at a first connection node;
a first leg that couples the first switch stage to a first switching node of the rectifier and that comprises a first capacitor and a first inductor connected in series;
a second switch stage coupled to the first switch stage such that the first switch stage is coupled in series between the input and the second switch stage, the second switch stage comprising a third switch and a fourth switch connected in series at a second connection node;
a second leg that couples the second connection node to the first switching node and that comprises a second capacitor and a second inductor connected in series;
a controller operable to control switching of the first switch stage and the second switch stage, so as to transfer energy between the input and the output, such that first switch conduction intervals are separated by first dead-time intervals during which neither the first switch nor the second switch conducts and such that second switch conduction intervals are separated by second dead-time intervals during which neither the third switch nor the fourth switch conducts;
and
a first compensation inductor coupled to the first leg and the second leg, the first compensation inductor configured to transfer charge to or from switch capacitances of the first switch and the second switch during the first dead-time intervals and to transfer charge to or from switch capacitances of the third switch and the fourth switch during the second dead-time intervals;
and
a load configured to be powered using the SCC.

11 more elements

Dependencies are inferred from the claim text.

Switched capacitor converter topology using a compensation inductor for charge transfer

Life of this patent

Switched capacitor converter topology using a compensation inductor for charge transfer

Life of this patent

Abstract

Claims20