Patent ID: 7701686

Claim:
A power supply controller disposed between a power source and a load for controlling power supply from said power source to said load, comprising: a semiconductor switching element disposed on a current path from said power source to said load; a current detecting element capable of detecting a current passing through said semiconductor switching element; an abnormal current detecting circuit for processing a signal from said current detecting element and thereby outputting an abnormal current signal if the current passing through said semiconductor switching element exceeds a predetermined threshold current; an overcurrent protective circuit for causing said semiconductor switching element to perform a disconnecting operation of a predetermined reference OFF duration and thereafter restoring a conducting state when a time has elapsed after the output of said abnormal current signal reaches a predetermined reference ON duration; a load protective circuit capable of measuring at least one of an accumulated time of a sum of said reference ON duration and said reference OFF duration or a number of times of said disconnecting operation associated with repetition of disconnection and restoration of said semiconductor switching element due to said overcurrent protective circuit, and causing said semiconductor switching element to perform a disconnecting operation on a condition that the measurement reaches a predetermined value; and a reset circuit for releasing a disconnecting state of said semiconductor switching element due to said load protective circuit based on an external signal and thereby restoring a conducting state.