Abstract: A gate driver 28 performs a normal charging operation for a power MOSFET 14 by driving a charge pump 90 solely, when a low-level control signal S1 (ON signal) is received during a normal state. On the other hand, if a low-level control signal S1 (ON signal) is received during a load anomaly state, an urgent charge FET 92, as well as the charge pump 90, is turned on when a load current IL exceeds a second anomaly threshold current ILfc, so that a rapid charging operation is performed.

Abstract: A parallel circuit 27 of a frequency control circuit 11 is provided as an external circuit. Thereby, the charging time t1 depends on the characteristics of the circuit elements, which are provided in the package of a semiconductor device 70 and therefore subject to manufacturing variations of the semiconductor device 70. The discharging time t2 depends on the parallel circuit 27, which is provided external to the semiconductor device 70 and therefore can be selected to have appropriate characteristics after the semiconductor device 70 has been manufactured. The circuit constants of circuits are set so that the discharging time t2 that depends on the device characteristics of the external parallel circuit 27 is longer than the charging time t1 that depends on the device characteristics of the internal circuits of the semiconductor device 70.

Abstract: In a power supply controller 10 having a self-protective mechanism for performing, intermittently or periodically, a forced ON-OFF operation which causes a power MOSFEET 15 to perform an automatically restorable primary disconnecting operation and a restoring operation when an overcurrent anomaly or an short-circuiting anomaly is detected, an automatically unrestorable secondary disconnecting operation is performed when the accumulated amount of the duration of the forced ON-OFF operation reaches an accumulation threshold.

Abstract: A power supply controller including a MOSFET between a power source and a load, a ground terminal, a gate driving circuit structured to control a gate potential of the MOSFET to turn on power and control the gate potential of the MOSFET to turn off power based on a ground terminal potential, and a turn-off circuit structured to switch the MOSFET into a turn-off state regardless of control by the gate driving circuit when the ground terminal potential is at a higher value than a source potential of the MOSFET.