Over-voltage protection circuit for a switched mode power supply

US7379310B2 · kind B2 · utility

Assignee

• Thomson Licensing · FR

Inventors

• Jean-Paul Louvel · Brigachtal, DE
• Daniel Lopez · Lemont, US
• Harald Grellmann · Königsfeld, DE

Key dates

• Filing date: Apr 22, 2005
• Grant date: May 27, 2008
• Expiry date: Oct 22, 2025

Classification

• Technology area (CPC H): Electricity
• CPC primary: H02M1/32
• WIPO field: Electrical machinery, apparatus, energy
• WIPO sector: Electrical engineering

Abstract

The switched mode power supply comprises an inductor, a switching transistor, a controller circuit coupled to the switching transistor, a rectifying means and a feedback regulation loop for providing a stabilised output voltage. It comprises further a protection circuit coupled to an output or input of a comparator of the controller circuit for providing an overvoltage protection in case of a failure of the regulation loop. The protection circuit comprises in particular an integrating circuit and a comparating circuit. In a preferred embodiment, an output of the protection circuit is coupled to a sense input of the controller circuit, for switching off the controller circuit immediately in case of a failure. In another aspect of the invention, the protection circuit comprises further a second comparator coupled to the first comparating circuit for the surveillance of the input voltage of the switched mode power supply, and for the detection of a short circuit of the inductor or the rectifying means.