# US 10,770,984 B2 · Switching control device with reverse bias circuit

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- Number: US 10,770,984 B2
- Document ID: US10770984B2
- Status: Granted
- Kind: B2
- Application number: 16/546,182
- Filed: 2019-08-20
- Published: 2019-12-05
- Granted: 2020-09-08
- Earliest claimed: 2017-03-21
- Assignees: Yazaki Corporation
- Applicants: Yazaki Corporation
- Inventors: Satoshi Ito
- Web page: https://patentgrep.com/patent/US10770984B2

## CPC

- H02M 3/33592: {having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary side of an isolation transformer}
- H03K 17/04123: {in field-effect transistor switches}
- H03K 17/691: using transformer coupling
- H03K 17/785: controlling field-effect transistor switches
- H03K 17/04163: {in field-effect transistor switches}
- H03K 2217/0081: Power supply means, e.g. to the switch driver
- 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)
- H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M)

## Abstract

A drive circuit is connected to a gate terminal of an FET connected to a DC power supply to be transformed and controlled to be turned on or off, and applies a voltage to the gate terminal to turn on the FET, the FET including a drain terminal to which a current is input, a source terminal that outputs the current input from the drain terminal, and the gate terminal that controls the current flowing from the drain terminal to the source terminal. A reverse bias circuit includes a capacitor connected to the source terminal of the FET, and a coil having one end connected between the drive circuit and the gate terminal and the other end connected between the capacitor and the source terminal.

## Claims

### Claim 1

A switching control device comprising:
a drive circuit that is connected to a control terminal of a switching element connected to a DC power supply to be transformed and controlled to be turned on or off, and applies a voltage to the control terminal to turn on the switching element, the switching element including an input terminal to which a current is input, an output terminal that outputs the current input from the input terminal, and the control terminal that controls the current flowing from the input terminal to the output terminal; and
a reverse bias circuit that includes a capacitor connected to the output terminal, and a coil having one end connected between the drive circuit and the control terminal and another end connected between the capacitor and the output terminal, wherein
the coil has an inductance value capable of continuously outputting a reverse bias voltage by the reverse bias circuit, and
when an inductance value of the coil is L, a voltage applied to the drive circuit is VCC2, an ON period per cycle during which the voltage is applied to the control terminal by the drive circuit is Ton, an OFF period per cycle during which the voltage is not applied to the control terminal by the drive circuit is Toff, and a current value of the control terminal which is applied by the drive circuit and predetermined as a design value is IG, according to:
L>(VCC2×Ton×Toff)/(2×IG×(Ton+Toff)) (1).