Patent ID: 7038525
Filing Date: 2006-05-02
Classification: H03K

Abstract:
1. A gradation selector circuit, comprising: a resistor circuit in which a plurality of resistive elements are connected in series between a high potential power source and a low potential power source; and a selector circuit connected to the resistor circuit, capable of selecting according to a control signal one of a plurality of analog voltages generated in the resistor circuit and outputting the selected analog voltage to an output terminal, the selector circuit comprising a plurality of analog switching circuits, wherein each of the plurality of analog switching circuits corresponds to one of the plurality of analog voltages, and wherein the analog switching circuit that selects one of the plurality of analog voltages having a potential substantially at the mid point of the potential between the high potential power source and the low potential power source comprises a transistor switch having at least one depletion mode transistor of one conductivity type in series with at least one enhancement mode transistor of another conductivity type between the resistor string circuit and the output terminal.