# US 8,542,501 B2 · Switching power-supply apparatus

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- Number: US 8,542,501 B2
- Document ID: US8542501B2
- Status: Granted
- Kind: B2
- Application number: 12/990,390
- Filed: 2009-10-27
- Published: 2011-03-03
- Granted: 2013-09-24
- Earliest claimed: 2008-10-30
- Assignees: Sanken Electric Co., Ltd.
- Applicants: Yoichi Kyono
- Inventors: Yoichi Kyono
- Web page: https://patentgrep.com/patent/US8542501B2

## CPC

- H02M 3/285: {Single converters with a plurality of output stages connected in parallel (parallel operation of a plurality of converters in DC distribution networks H02J1/10)}
- H02M 1/0058: {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)}
- Y02B 70/10: Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
- H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P)
- Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS

## Abstract

A switching power-supply apparatus includes a first converter 3, a second converter 4, an output smoothing capacitor Co1, a series resonance circuit 1 and a control circuit 11. The first converter 3, in which switching elements Q11 and Q12 are connected to both ends of a direct-current power-supply Vin in series, and a capacitor Ci1 and a primary winding Np1 of a transformer T1 including an auxiliary winding Na1 are connected to both ends of the switching element Q12 in series, includes diodes D11 and D12 that rectify voltages generated in secondary windings Ns11 and Ns12 of the transformer T1. The second converter 4, in which switching elements Q21 and Q22 are connected to the both ends of the direct-current power-supply Vin in series, and a capacitor Ci12 and a primary winding Np2 of a transformer T2 are connected to both ends of the switching element Q22 in series, includes diodes D21 and D22 that rectify voltages generated in secondary windings Ns21 and Ns22 of the transformer T2. The output smoothing capacitor Co1 smoothes currents output from the diodes D11, D12, D21 and D22. The series resonance circuit 1 includes a resonance reactor L1 and a resonance capacitor C1 connected to the auxiliary winding Na1 in series. The control circuit 11 turns on/off the switching elements Q21 and Q22 according to a current flowing in the series resonance circuit 1.

## Claims

### Claim 1

A switching power-supply apparatus comprising:
a first transformer including a primary winding, a secondary winding and an auxiliary winding;
a second transformer including a primary winding and a secondary winding;
a first converter in which a first switching element and a second switching element are connected to both ends of a direct-current power-supply in series, and a first capacitor and the primary winding of the first transformer are connected to both ends of the first switching element or the second switching element in series, wherein the first converter includes a first rectifying circuit that rectifies a voltage generated in the secondary winding of the first transformer;
a second converter in which a third switching element and a fourth switching element are connected to both ends of the direct-current power-supply in series, and a second capacitor and the primary winding of the second transformer are connected to both ends of the third switching element or the fourth switching element in series, wherein the second converter includes a second rectifying circuit that rectifies a voltage generated in the secondary winding of the second transformer;
a smoothing circuit that smoothes currents output from the first rectifying circuit and the second rectifying circuit;
a series resonance circuit that includes a resonance reactor and a resonance capacitor and is connected to the auxiliary winding of the first transformer in series; and
a control circuit that turns on/off the third switching element and the fourth switching element according to a polarity of a current flowing in the series resonance circuit, wherein a phase of the current is delayed by 90 degrees with respect to a phase of a voltage generated in the auxiliary winding of the first transformer,
wherein the second converter is operated out of phase with the first converter by 90 degrees.

### Claim 2 (depends on 1)

The switching power-supply apparatus according to claim 1, wherein the control circuit turns on the third switching element when a current flowing in the series resonance circuit is positive, and turns on the fourth switching element when a current flowing in the series resonance circuit is negative.

### Claim 3 (depends on 1)

The switching power-supply apparatus according to claim 1, wherein a first power factor improvement circuit and a second power factor improvement circuit are substituted for the direct-current power-supply,
the first power factor improvement circuit turns on/off a rectified voltage generated by rectifying an alternating-current voltage of an alternating-current power-supply using a first switch to improve a power factor, and converts the rectified voltage into a certain direct-current voltage and supplies the certain direct-current voltage to the first converter, and
the second power factor improvement circuit turns on/off a rectified voltage generated by rectifying the alternating-current voltage using a second switch to improve a power factor, and converts the rectified voltage into a direct-current voltage with a turn-on width which is the same as a turn-on width of the first switch of the first power factor improvement circuit and supplies the direct-current voltage to the second converter.

### Claim 4 (depends on 1)

The switching power-supply apparatus according to claim 1, wherein a voltage dividing direct-current power-supply is substituted for the direct-current power-supply,
a first voltage dividing capacitor and a second voltage dividing capacitor are connected to both ends of the voltage dividing direct-current power-supply in series,
a direct-current voltage of the first voltage dividing capacitor is supplied to the first converter, and
a direct-current voltage of the second voltage dividing capacitor is supplied to the second converter.

### Claim 5

A switching power-supply apparatus comprising:
a first transformer including a primary winding, a secondary winding, a first auxiliary winding and a second auxiliary winding wound to have a reversed polarity with respect to the first auxiliary winding;
a second transformer including a primary winding and a secondary winding;
a first converter in which a first switching element and a second switching element are connected to both ends of a direct-current power-supply in series, and a first capacitor and the primary winding of the first transformer are connected to both ends of the first switching element or the second switching element in series, wherein the first converter includes a first rectifying circuit that rectifies a voltage generated in the secondary winding of the first transformer;
a second converter in which a third switching element and a fourth switching element are connected to both ends of the direct-current power-supply in series, and a second capacitor and the primary winding of the second transformer are connected to both ends of the third switching element or the fourth switching element in series, wherein the second converter includes a second rectifying circuit that rectifies a voltage generated in the secondary winding of the second transformer;
a smoothing circuit that smoothes currents output from the first rectifying circuit and the second rectifying circuit;
a first series resonance circuit that includes a first resonance reactor and a first resonance capacitor and is connected to the first auxiliary winding of the first transformer in series;
a first control circuit that turns on/off the third switching element according to a polarity of a current of the first series resonance circuit, wherein a phase of the current is delayed by 90 degrees with respect to a phase of a voltage generated in the first auxiliary winding of the first transformer;
a second series resonance circuit that includes a second resonance reactor and a second resonance capacitor and is connected to the second auxiliary winding of the first transformer in series; and
a second control circuit that turns on/off the fourth switching element according to a polarity of a current of the second series resonance circuit, wherein a phase of the current is delayed by 90 degrees with respect to a phase of a voltage generated in the auxiliary winding of the first transformer,
wherein the second converter is operated out of phase with the first converter by 90 degrees.

### Claim 6 (depends on 5)

The switching power-supply apparatus according to claim 5, wherein a first power factor improvement circuit and a second power factor improvement circuit are substituted for the direct-current power-supply,
the first power factor improvement circuit turns on/off a rectified voltage generated by rectifying an alternating-current voltage of an alternating-current power-supply using a first switch to improve a power factor, and converts the rectified voltage into a certain direct-current voltage and supplies the certain direct-current voltage to the first converter, and
the second power factor improvement circuit turns on/off a rectified voltage generated by rectifying the alternating-current voltage using a second switch to improve a power factor, and converts the rectified voltage into a direct-current voltage with a turn-on width which is the same as a turn-on width of the first switch of the first power factor improvement circuit and supplies the direct-current voltage to the second converter.

### Claim 7 (depends on 5)

The switching power-supply apparatus according to claim 5, wherein a voltage dividing direct-current power-supply is substituted for the direct-current power-supply,
a first voltage dividing capacitor and a second voltage dividing capacitor are connected to both ends of the voltage dividing direct-current power-supply in series,
a direct-current voltage of the first voltage dividing capacitor is supplied to the first converter, and
a direct-current voltage of the second voltage dividing capacitor is supplied to the second converter.

### Claim 8

A switching power-supply apparatus comprising:
a first converter in which a first switching element and a second switching element are connected to both ends of a direct-current power-supply in series, and a first capacitor and a primary winding of a first transformer including a first auxiliary winding and a second auxillary winding, each of which is wound to have a reversed polarity with respect to the other winding, are connected to both ends of the first switching element or the second switching element in series, wherein the first converter includes a first rectifying circuit that rectifies a voltage generated in a secondary winding of the first transformer;
a second converter in which a third switching element and a fourth switching element are connected to the both ends of the direct-current power-supply in series, and a second capacitor and a primary winding of a second transformer are connected to both ends of the third switching element or the fourth switching element in series, wherein the second converter includes a second rectifying circuit that rectifies a voltage generated in a secondary winding of the second transformer;
a smoothing circuit that smoothes currents output from the first rectifying circuit and the second rectifying circuit;
a first series resonance circuit that includes a first resonance reactor and a first resonance capacitor and is connected to the first auxiliary winding in series;
a first control circuit that turns on/off the third switching element according to a current of the first series resonance circuit;
a second series resonance circuit that includes a second resonance reactor and a second resonance capacitor and is connected to the second auxiliary winding in series; and
a second control circuit that turns on/off the fourth switching element according to a current of the second series resonance circuit,
wherein the first control circuit includes a first drive circuit in which first and second transistors totem-pole connected are included, respective base terminals of the first and second transistors are connected to one end of a series circuit including the first series resonance circuit and the first auxiliary winding, and respective emitter terminals of the first and second transistors are connected to the other end of the series circuit including the first series resonance circuit and the first auxiliary winding and a control terminal of the third switching element, and
the second control circuit includes a second drive circuit in which third and fourth transistors totem-pole connected are included, respective base terminals of the third and fourth transistors are connected to one end of a series circuit including the second series resonance circuit and the second auxiliary winding, and respective emitter terminals of the third and fourth transistors are connected to the other end of the series circuit including the second series resonance circuit and the second auxiliary winding and a control terminal of the fourth switching element.

### Claim 9 (depends on 8)

The switching power-supply apparatus according to claim 8, wherein each of the first drive circuit and the second drive circuit includes a diode connected between a base terminal and a collector terminal of each transistor.

### Claim 10

A switching power-supply apparatus comprising:
a first converter in which a first switching element and a second switching element are connected to both ends of a direct-current power-supply in series, and a first capacitor and a primary winding of a first transformer a first auxiliary winding and a second auxiliary winding, each of which is would to have reversed polarity with respect to the other winding, are connected to both ends of the first switching element or the second switching element in series, wherein the first converter includes a first rectifying circuit that rectifies a voltage generated in a secondary winding of the first transformer;
a second converter in which a third switching element and a fourth switching element are connected to the both ends of the direct-current power-supply in series, and a second capacitor and a primary winding of a second transformer are connected to both ends of the third switching element or the fourth switching element in series, wherein the second converter includes a second rectifying circuit that rectifies a voltage generated in a secondary winding of the second transformer;
a smoothing circuit that smoothes currents output from the first rectifying circuit and the second rectifying circuit;
a first series resonance circuit that includes a first resonance reactor and a first resonance capacitor and is connected to the first auxiliary winding in series;
a first control circuit that turns on/off the third switching element according to a current of the first series resonance circuit;
a second series resonance circuit that includes a second resonance reactor and a second resonance capacitor and is connected to the second auxiliary winding in series; and
a second control circuit that turns on/off the fourth switching element according to a current of the second series resonance circuit,
wherein the first control circuit includes a first drive circuit in which first and second transistors totem-pole connected are included, respective base terminals and respective collector terminals of the first and second transistors are connected to one end of a series circuit including the first series resonance circuit and the first auxiliary winding via diodes, respective emitter terminals of the first and second transistors are connected to the other end of the series circuit including the first series resonance circuit and the first auxiliary winding and a control terminal of the third switching element, and a resistor is connected between the base terminal and the emitter terminal of the first transistor and
the second control circuit includes a second drive circuit in which third and fourth transistors totem-pole connected are included, respective base terminals and respective collector terminals of the third and fourth transistors are connected to one end of a series circuit including the second series resonance circuit and the second auxiliary winding via diodes, respective emitter terminals of the third and fourth transistors are connected to the other end of the series circuit including the second series resonance circuit and the second auxiliary winding and a control terminal of the fourth switching element, and a resistor is connected between the base terminal and the emitter terminal of the third transistor.

### Claim 11

A switching power-supply apparatus comprising:
a first transformer including a primary winding and a secondary winding;
a second transformer including a primary winding and a secondary winding;
a first converter in which a first switching element and a second switching element are connected to both ends of a direct-current power-supply in series, and a first capacitor and the primary winding of the first transformer are connected to both ends of the first switching element or the second switching element in series, wherein the first converter includes a first rectifying circuit that rectifies a voltage generated in the secondary winding of the first transformer;
a second converter in which a third switching element and a fourth switching element are connected to both ends of the direct-current power-supply in series, and a second capacitor and the primary winding of the second transformer are connected to both ends of the third switching element or the fourth switching element in series, wherein the second converter includes a second rectifying circuit that rectifies a voltage generated in the secondary winding of the second transformer;
a smoothing circuit that smoothes currents output from the first rectifying circuit and the second rectifying circuit;
a series resonance circuit that includes a resonance reactor and a resonance capacitor connected to both ends of the first switching element or the second switching element; and
a control circuit that turns on/off the third switching element and the fourth switching element according to a polarity of a current flowing in the series resonance circuit, wherein a phase of the current is delayed by 90 degrees with respect to a phase of a voltage generated in the primary winding of the first transformer,
wherein the second converter is operated out of phase with the first converter by 90 degrees.

### Claim 12 (depends on 11)

The switching power-supply apparatus according to claim 11, wherein a first power factor improvement circuit and a second power factor improvement circuit are substituted for the direct-current power-supply,
the first power factor improvement circuit turns on/off a rectified voltage generated by rectifying an alternating-current voltage of an alternating-current power-supply using a first switch to improve a power factor, and converts the rectified voltage into a certain direct-current voltage and supplies the certain direct-current voltage to the first converter, and
the second power factor improvement circuit turns on/off a rectified voltage generated by rectifying the alternating-current voltage using a second switch to improve a power factor, and converts the rectified voltage into a direct-current voltage with a turn-on width which is the same as a turn-on width of the first switch of the first power factor improvement circuit and supplies the direct-current voltage to the second converter.

### Claim 13 (depends on 11)

The switching power-supply apparatus according to claim 11, wherein a voltage dividing direct-current power-supply is substituted for the direct-current power-supply,
a first voltage dividing capacitor and a second voltage dividing capacitor are connected to both ends of the voltage dividing direct-current power-supply in series,
a direct-current voltage of the first voltage dividing capacitor is supplied to the first converter, and
a direct-current voltage of the second voltage dividing capacitor is supplied to the second converter.

### Claim 14

A switching power-supply apparatus comprising:
a first transformer including a primary winding, a secondary winding and an auxiliary winding;
a second transformer including a primary winding and a secondary winding;
a third transformer including a primary winding, a first secondary winding and a second secondary winding wound to have a reversed polarity with respect to the first secondary winding;
a first converter in which a first switching element and a second switching element are connected to both ends of a direct-current power-supply in series, a first capacitor and the primary winding of the first transformer are connected to both ends of the first switching element or the second switching element in series, and third capacitor and the primary winding of the third transformer are connected to both ends of the first switching element or the second switching element in series, wherein the first converter includes a first rectifying circuit that rectifies a voltage generated in the secondary winding of the first transformer;
a second converter in which a third switching element and a fourth switching element are connected to both ends of the direct-current power-supply in series, and a second capacitor and the primary winding of the second transformer are connected to both ends of the third switching element or the fourth switching element in series, wherein the second converter includes a second rectifying circuit that rectifies a voltage generated in the secondary winding of the second transformer;
a smoothing circuit that smoothes currents output from the first rectifying circuit and the second rectifying circuit;
a first series resonance circuit that includes a first resonance reactor and a first resonance capacitor and is connected to the first secondary winding of the third transformer in series;
a first control circuit that turns on/off the third switching element according to a polarity of a current flowing in the first series resonance circuit, wherein a phase of the current is delayed by 90 degrees with respect to a phase of a voltage generated in the first secondary winding of the third transformer;
a second series resonance circuit that includes a second resonance reactor and a second resonance capacitor and is connected to the second secondary winding of the third transformer in series; and
a second control circuit that turns on/off the fourth switching element according to a polarity of a current flowing in the second series resonance circuit, wherein a phase of the current is delayed by 90 degrees with respect to a phase of a voltage generated in the second secondary winding of the third transformer,
wherein the second converter is operated out of phase with the first converter by 90 degrees.

### Claim 15 (depends on 14)

The switching power-supply apparatus according to claim 14, wherein a first power factor improvement circuit and a second power factor improvement circuit are substituted for the direct-current power-supply,
the first power factor improvement circuit turns on/off a rectified voltage generated by rectifying an alternating-current voltage of an alternating-current power-supply using a first switch to improve a power factor, and converts the rectified voltage into a certain direct-current voltage and supplies the certain direct-current voltage to the first converter, and
the second power factor improvement circuit turns on/off a rectified voltage generated by rectifying the alternating-current voltage using a second switch to improve a power factor, and converts the rectified voltage into a direct-current voltage with a turn-on width which is the same as a turn-on width of the first switch of the first power factor improvement circuit and supplies the direct-current voltage to the second converter.

### Claim 16 (depends on 14)

The switching power-supply apparatus according to claim 14, wherein a voltage dividing direct-current power-supply is substituted for the direct-current power-supply,
a first voltage dividing capacitor and a second voltage dividing capacitor are connected to both ends of the voltage dividing direct-current power-supply in series,
a direct-current voltage of the first voltage dividing capacitor is supplied to the first converter, and
a direct-current voltage of the second voltage dividing capacitor is supplied to the second converter.