POWER CONTROL CIRCUIT

摘要

PURPOSE: A power control circuit is provided to extend the lifetime of a power circuit and an output terminal by stopping the operation of the power circuit in a no-load condition. CONSTITUTION: A power circuit includes an output current detecting unit(24) and a pulse width modulation control unit(25). The output current detecting unit detects a predetermined level of current flowing in an output terminal. The pulse width modulation control unit stops the operation of a pulse width modulation unit by outputting a reset signal to the pulse width modulation unit(23) after a predetermined delay time in a no-load condition. The pulse width modulation control unit uses one or more of an integrating circuit, a darlington circuit, and a hysteresis circuit for securing a long delay time.