Patent Number: 7,355,830

Title: Overcurrent protection device

Abstract: The switching regulator comprises a main switch, a rectifier switch, an RS-flipflop, a judging unit, an edge pulse generator, a second prohibiting unit, and a reference voltage source. When a voltage drop caused due to an on-resistance of the main switch exceeds a predetermined value, the judging unit sets a set signal of the RS-flipflop at a high level, and thereby an overcurrent is cut off. The edge pulse generator monitors a gate voltage of the rectifier switch, and sets a prohibition signal at a high level for a predetermined time period from the trailing edge. Then, the second prohibiting unit sets the set signal at a low level, and prohibits cutting the overcurrent off. Herewith, the likelihood that the main switch will be destroyed by the overcurrent can be reduced.

Inventors: Motomori; Mikio (Hirakata, JP)

Assignee: Matsushita Electric Industrial Co., Ltd.

International Classification: H02H 3/00 (20060101)

Expiration Date: 2020-04-08 0:00:00