Voltage-current converter

摘要

The present invention provides a voltage-current converter which can decrease the circuit scale excluding the capacitor for the stability operation, and which can select one from among two or more output currents is disclosed. Constant voltage Vr generated in constant voltage source 90 is supplied to non-reversing input of op-amp 10, output Vo of op-amp 10 returns to the reversing input of op-amp 10, and the output Vo is connected with resistance R. The gate voltage Va of the P channel MOS transistor and the gate voltage Vb of the N-channel MOS transistor which configure the output circuit of the op-amp 10 is outputted and is supplied to the constant current generation circuit 30. Constant current generation circuit 30 outputs constant current I2 from these voltages Va and Vb.