VOLTAGE-CURRENT CONVERSION CIRCUIT

摘要

PROBLEM TO BE SOLVED: To provide a voltage-current conversion circuit, by which the current signals of multiple channels are generated with high accuracy and power consumption is reduced. SOLUTION: Operational amplifiers A1-A3 and transistors Q1 and Q2 are designed to operate at a low operating voltage. A D/A converter 4 inputs a voltage signal 101 to a voltage signal input circuit composed of the operational amplifier A1 and performs voltage-current conversion. A level converting circuit composed of the transistor Q1 and resistors R1 and R2 generates a level converting signal 102. A buffer circuit composed of the operational amplifier A2 inputs the level converting signal 102 through a multiplexer U1 to a capacitor C1 for sample-and-hold. A current output circuit composed of the operational amplifier A3, the transistor Q2 and a resistor R3 generate a current signal 104 from the held signal.