Clamp circuit for a semiconductor integrated circuit device

摘要

A comparator, having an offset of 0.1V, compares a terminal voltage Vin1 with a clamp voltage VCL(5.1V). When an overvoltage input exceeding the VCL is entered to an input terminal, the comparator turns on a transistor Q11. The current flows across an externally provided resistor R11, the input terminal, and the transistor Q11, and flows into an output terminal of an operational amplifier. With a voltage drop at the resistor R11, the terminal voltage Vin1 starts decreasing toward an output voltage Vc of the operational amplifier.