Patent ID: 10637232

Abstract:
An internal electric circuit device that is connected to a connector terminal at the time of being short-circuited can be protected, but a load connected to the connector terminal has not been able to be protected. When a voltage of a cathode of a diode becomes a voltage equal to or more that an output voltage of a power source circuit by a short circuit of a positive terminal, an output voltage of an amplifier changes from the output voltage of the power source circuit to a voltage of a point connected to a negative power terminal of the OP amplifier. When the output voltage of the amplifier becomes 0 V, a voltage difference between the gate and the source of a switching element becomes equal to or more than a predetermined voltage. Therefore, the drain and the source of the switching element enter an open state, and the current flowing a negative terminal is blocked. Therefore, it is possible to protect a load from overcurrent.