Switching power supply circuit having constant output for a wide range of input voltage
US4389702A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 27, 1982 |
| Grant date | Jun 21, 1983 |
| Priority date | — |
| Expiry date | Aug 27, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02M3/33546
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A switching power supply is disclosed using a single transistor circuit which provides a constant output voltage for a range of input voltages extending from a nominal 115 volt power supply to a nominal 220/240 volt power supply without requiring a change in the circuit configuration throughout the range of input voltages. The circuit is disclosed in connection with a single transistor forward converter circuit, in which the transformer winding of the converter circuit is provided with a uni-directional clamp to prevent the transformer voltage of a given polarity from exceeding the clamping voltage magnitude. By clamping one polarity of the transformer voltage which is in series with the switching transistor, the maximum peak-to-peak voltage on the transistor is reduced from that which would be produced in the absence of clamping and enables the use of a power MOSFET transistor for the circuit. The clamping circuit is disclosed as a zener clamp and as a circuit including a parallel resistor and capacitor and series diode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.