Abstract: In a clamping circuit comprising a voltage comparator for comparing an input signal voltage supplied to the signal input terminal and a reference voltage, a clamping circuit of the present invention comprises a bias voltage supplying circuit and a switch circuit inserted between the bias voltage supplying circuit and the signal input terminal. The input signal voltage is compared with the reference voltage by the voltage comparator, and the switch circuit is ON/OFF-controlled on the basis of the comparison result. When the switch circuit is enabled, a bias voltage of the bias voltage supplying circuit is supplied to the signal input terminal, and the input signal voltage is clamped at a voltage equal to the reference voltage. When the switch circuit comprises a CMOS transfer gate, a voltage drop does not occur across the switch circuit regardless of the value of the bias voltage.

Abstract: In a semiconductor circuit including a wave shaper circuit and a driver circuit, the wave shaper circuit is supplied with the reference potential via a wiring, which is provided independent of a wiring for supplying the reference potential to a driver circuit. With this feature, a variation in the potential of the wiring for supplying the reference potential to the wave shaper circuit is minimized.