# US 4,899,271 A · Power supply circuit

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- Number: US 4,899,271 A
- Document ID: US4899271A
- Status: Granted
- Kind: A
- Application number: 07/222,207
- Filed: 1988-07-21
- Granted: 1990-02-06
- Earliest claimed: 1987-07-22
- Assignees: Scanpower
- Inventors: Ole S. Seiersen
- Web page: https://patentgrep.com/patent/US4899271A

## CPC

- H02M 7/06: using discharge tubes without control electrode or semiconductor devices without control electrode
- 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 power supply circuit comprising a transformer and rectifier diodes, where the ends of the secondary winding are connected to uniform first electrodes of a pair of rectifier diodes (D1, D2) whose second electrodes are connected to one output terminal (-) of the power supply circuit. According to the invention, also reactive components are provided, said reactive components being connected between the other output terminal (+) of the power supply circuit and the first electrode of respective ones of the rectifier diodes. When one reactance (e.g. L2) can send current (I.sub.L2) through one (D2) rectifier diode serving as an idler diode, while the secondary winding of the transformer draws current (I.sub.L1) through the same rectifier diode, a better utilization of the transformer is obtained than in the prior art, in particular when the output voltage is relatively low, while the output current is relatively high.

## Claims

### Claim 1

A power supply circuit comprising a transformer including a secondary winding having two secondary winding ends, and a pair of rectifier diodes each diode having a first type of electrode and a second type of electrode, each of the diodes having a first type of its electrodes connected directly to a respective one of the secondary winding ends, the second electrode of each of the diodes being connected to a first output terminal of the power supply circuit,
characterized in that the power supply circuit further comprises two reactive components wherein the first type electrodes of the diodes are further connected to the second output terminal of the power supply circuit via a respective one of the reactive components such that the sum of the current through the diodes is substantially equal to the output current, and that the reactive components are dimensioned such that one reactive component sends current through one diode serving as a free-wheeling diode, while the secondary winding of the transformer sends current through the same diode.

### Claim 2 (depends on 1)

A circuit according to claim 1, wherein the reactive components comprise a common magnet core so adapted that the magnetic coupling between the reactive components is insignificant in practice.

### Claim 3 (depends on 1, 2)

A circuit according to claim 1 or 2, characterized in that the reactive components are of the non-linear type, where the self-induction increases when the current intensity diminishes.