Protection circuit for a switched mode power supply

• Main Authors: Lopez, Daniel, Louvel, Jean-Paul, Grellmann, Harald
• Format: Patent
• Language: English; French; German
• Published: 16.05.2018
• Subjects: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC,OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWERSUPPLY SYSTEMS; CONTROL OR REGULATION THEREOF; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUTPOWER; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER; ELECTRICITY; GENERATION

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 (PC) 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 (IN1) and a comparating circuit (CO1). In a preferred embodiment, an output (E') 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.