Patent ID: 7499298

Claim:
A semiconductor integrated circuit comprising: a power supply circuit; a voltage-current conversion circuit connected with an output of the power supply circuit, the voltage-current conversion circuit having an output terminal; a current-voltage conversion circuit connected with the output terminal of the voltage-current conversion circuit, the current-voltage conversion circuit having an output terminal; first voltage line connected with the output terminal of the current-voltage conversion circuit; an output circuit which has an output terminal to which an external element is connected at a rear stage thereof; and a protection circuit which is connected to the first voltage line and the output circuit, receives a potential of the first voltage line and the output signal from the power supply circuit to control a potential of the output terminal, and prevents the external element from operating when an increase in the potential of the first voltage line is insufficient or the power supply voltage is not in a steady state, a second voltage line which connects an external supply power to the power supply circuit, the voltage-current conversion circuit, the current-voltage conversion circuit and the output circuit, wherein the power supply circuit, the current-voltage conversion circuit, the protection circuit and the output circuit are commonly grounded.