Patent ID: 7813096

Claim:
A power supply controller for controlling power supply from a power source to a load, comprising: a semiconductor switching element disposed on a power supply line from said power source to said load; a current detecting element configured to detect a load current passing through said semiconductor switching element; a first abnormal current detecting circuit configured to determine, based on a detection signal from said current detecting element, whether a load current passing through said semiconductor switching element exceeds a first threshold, and further configured to output a first abnormal current signal if said load current exceeds said first threshold; an anomaly time accumulator circuit configured to start accumulation of an anomaly time if said first abnormal current detecting circuit outputs said first abnormal current signal, and further configured to initiate a first shutoff operation for said semiconductor switching element when said anomaly time reaches a first reference time; a normal duration accumulator circuit configured to output a clear signal when a normal duration, during which said load current is continuously maintained lower than said first threshold, reaches a second reference time after said anomaly time accumulator circuit starts the accumulation; and an anomaly time clear circuit configured to clear said anomaly time of said anomaly time accumulator circuit based on an output of said clear signal.