Switch mode power supply with separately regulated secondary voltage

US4912617A · kind A · utility

Assignee

• Deutsche Thomson-Brandt GmbH · DE

Inventors

• Uwe Hartmann · Stuttgart, DE
• Udo Mai · Hauzenberg, DE

Key dates

• Filing date: Sep 19, 1988
• Grant date: Mar 27, 1990
• Expiry date: Sep 19, 2008

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02B70/10
• WIPO field: Electrical machinery, apparatus, energy
• WIPO sector: Electrical engineering

Abstract

A primary winding of a transformer is coupled to a source of input voltage and to a controllable switch. The switch is responsive to a first control signal for generating output pulses in the transformer secondary windings. A supply circuit is responsive to the output pusles and generates a first supply voltage. A capacitor charging circuit includes a thyristor that is coupled to one of the transformer secondary windings. The thyristor receives the output pulses for providing charging pulses to the capacitor for generating a second supply voltage. A control circuit is coupled to the thyristor for varying the number of output pulses occurring relative to a given number of charging pulses to regulate the second supply voltage.