# US 8,541,998 B2 · Switching converter circuit

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- Number: US 8,541,998 B2
- Document ID: US8541998B2
- Status: Granted
- Kind: B2
- Application number: 13/211,523
- Filed: 2011-08-17
- Published: 2012-03-01
- Granted: 2013-09-24
- Earliest claimed: 2010-08-25
- Assignees: Ricoh Company, Ltd.
- Applicants: Shunsei Tanaka
- Inventors: Shunsei Tanaka
- Web page: https://patentgrep.com/patent/US8541998B2

## CPC

- H02M 3/156: with automatic control of output voltage or current, e.g. switching regulators
- 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)

## Abstract

A switching converter circuit utilized for converting voltages applied to a first input terminal and a second input terminal into constant voltages to output the constant voltages to a load includes a first switching unit connected between the first and the second input terminals, a second switching unit cascade connected with a third switching unit between the second input terminal and an output terminal, a fourth switching unit connected in parallel with the second and the third switching units, a first comparator to control switching on or off of the third switching unit, a second comparator to control switching on or off of the fourth switching unit, and a controller to control a time to allow the first comparator to output an output signal such that the fourth switching unit is switched off before the third switch is switched off based on the signal output from the first comparator.

## Claims

### Claim 1

A switching converter circuit having a first input terminal, a second input terminal and an output terminal, and utilized for converting voltages applied to the first input terminal and the second input terminal into constant voltages to output the constant voltages to a load, the switching converter circuit comprising:
a first switching unit connected between the first input terminal and the second input terminal;
a second switching unit and a third switching unit configured to be cascade connected with each other between the second input terminal and the output terminal;
a fourth switching unit connected in parallel with the second switching unit and the third switching unit;
a first comparator configured to control switching on or off of the third switching unit;
a second comparator configured to control switching on or off of the fourth switching unit; and
a controller configured to control a time to allow the first comparator to output an output signal such that the fourth switching unit is switched off before the third switch is switched off based on the signal output from the first comparator.

### Claim 2 (depends on 1)

The switching converter circuit as claimed in claim 1, wherein
the fourth switching unit is connected in parallel with the second switching unit.

### Claim 3 (depends on 1)

The switching converter circuit as claimed in claim 1, wherein
the fourth switching unit is connected in parallel with the third switching unit.