LED drive circuit, has resistors parallely switched, and current acquisition feedback unit forming protective circuit to reduce rise of output power if fed voltage of alternating current source is high

摘要

The circuit has a protection unit (10) attached to an alternating current source (60). An end of a first resistor is electrically connected with a transistor at an end of a second resistor and an end of the third resistor. The second and third resistors are parallely switched, and another end of the second resistor and another end of the third resistor are grounded. A current acquisition feedback unit (50) forms a protective circuit to reduce a rise of an output power if the fed voltage of the alternating current source is high.