# US 10,374,518 B2 · DC-DC converter

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- Number: US 10,374,518 B2
- Document ID: US10374518B2
- Status: Granted
- Kind: B2
- Application number: 16/042,726
- Filed: 2018-07-23
- Published: 2019-01-24
- Granted: 2019-08-06
- Earliest claimed: 2017-07-24
- Assignees: Calsonic Kansei Corporation; National University Corporation Hokkaido University; Utsunomiya University
- Applicants: Calsonic Kansei Corporation; National University Corporation Hokkaido University; Utsunomiya University
- Inventors: Fumihiro Okazaki; Satoshi Ogasawara; Hirohito Funato; Kousuke Aoki
- Web page: https://patentgrep.com/patent/US10374518B2

## CPC

- H02M 3/33592: {having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary side of an isolation transformer}
- H02M 3/33571: {Half-bridge at primary side of an isolation transformer}
- 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)}
- H02M 3/01: {Resonant DC/DC converters}
- 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 direct current (DC)-DC converter includes: a transformer; a half bridge circuit provided on a primary side of the transformer; a synchronous rectification circuit provided on a secondary side of the transformer; and a controller configured to switch a power semiconductor device for rectification of the synchronous rectification circuit at a duty ratio and a phase corresponding to an input voltage of the half bridge circuit and an output current of the synchronous rectification circuit.

## Claims

### Claim 1

A direct current (DC)-DC converter comprising:
a transformer;
a half bridge circuit provided on a primary side of the transformer;
a synchronous rectification circuit provided on a secondary side of the transformer; and
a controller configured to switch a power semiconductor device for rectification of the synchronous rectification circuit at a duty ratio and a phase corresponding to an input voltage of the half bridge circuit and an output current of the synchronous rectification circuit,
wherein the controller is configured to determine the duty ratio at a time of switching the power semiconductor device for rectification with reference to a table of duty ratios in which a combination of the input voltage and the output current and the duty ratio corresponding to the combination are mapped to each other, and
wherein the duty ratios in the table increase as the input voltage becomes higher.

### Claim 2 (depends on 1)

The DC-DC converter according to claim 1, wherein the controller is configured to determine the phase at the time of switching the power semiconductor device for rectification with reference to a table of phases in which a combination of the input voltage and the output current and a phase corresponding to the combination are mapped to each other.

### Claim 3 (depends on 1)

The DC-DC converter according to claim 1, wherein the controller is configured to refer to the table per control cycle of switching of the power semiconductor device for rectification with respect to at least one of two power semiconductor devices for rectification of the synchronous rectification circuit.

### Claim 4 (depends on 1)

The DC-DC converter according to claim 1, wherein the phase is defined by a phase delay with respect to a phase of switching of the power semiconductor device for inverse conversion of the half bridge circuit.

### Claim 5 (depends on 1)

The DC-DC converter according to claim 1, wherein the controller is configured to switch each of two power semiconductor devices to rectify the synchronous rectification circuit at a same duty ratio.