Analog switching circuit and gradation selector circuit

摘要

A gradation selector circuit provided with a resistor string circuit in which resistive elements are connected in series between a high potential power source and a low potential power source and a selector circuit which is connected to the resistor string circuit, which selects one of plural analog voltages generated in the resistor string circuit according to a control signal and which outputs it to an output terminal is used. The selector circuit includes analog switching circuits that select analog voltage close to intermediate potential. The analog switching circuit includes a P-type MOS transistor to the source electrode and the back gate electrode of which the resistor string circuit is connected and a depletion type N-type MOS transistor to the source electrode of which the drain electrode of the P-type MOS transistor is connected and to the drain electrode of which an output terminal is connected.