Initial potential setting circuit for a sample/hold circuit associated

Abstract

One of analog input voltages applied to a plurality of analog input terminals is selected by means of analog switches connected to the respective analog input terminals and supplied to a common terminal. In this case, each of the analog switches permits selective supply of the potential of a corresponding one of the plurality of analog input terminals in response to a control signal supplied from a controller. The common terminal is connected to the positive input terminal of a comparator. The comparator compares the voltage with a digital output value from the controller which is converted into an analog voltage by means of a D/A converter. Further, the controller generates a preset control signal in an inhibition period during which supply of a voltage from the plurality of analog input terminals to the common terminal is inhibited. An initial potential setting circuit sets the potential of the common terminal to a voltage level equal to substantially one-half the maximum voltage level of the analog input voltages applied to the plurality of analog input terminals.