Patent Number: 8,716,954

Title: LED drive circuit

Abstract: An LED drive circuit for driving an LED includes a reactor L1, a switch element, a current detection resistor R1 to detect a current of the switch element, a constant current circuit 2 that generates a first control signal to control a current of the switch element to be constant, a disconnection detection circuit 4a that generates a second control signal to keep the switch element OFF if determining that a current equal to or over a predetermined value passes through the switch element when a predetermined time elapses after the timing at which the switch element changes its state from ON to OFF, and a driver of the switch element that drives the switch element and keeps the switch element OFF in case of a disconnection according to the second control signal in priority to the first control signal.

Inventors: Takahashi; Kazuhiro (Niiza, JP), Furukawa; Naoharu (Nizza, JP), Domon; Hiroshi (Niiza, JP)

Assignee: Sanken Electric Co., Ltd.

International Classification: H05B 37/02 (20060101)

Expiration Date: 5/06/12018