A protection circuit for protecting DCDC converter With a power MOS transistor from start-up in-rush current includes a coupling capacitor and a Voltage clamping circuit.
By using the coupling capacitor to turn-off the power MOS transistor, there is no current consumed during the normal operation of the circuit. Enable signal or leakage current circuit is used to discharge the capacitor so that the circuitry can work in another turning-on of power supply.