CONSTANT VOLTAGE CONTROL CIRCUIT

摘要

PURPOSE:To attain the low power consumption and high accuracy of a constant voltage supply control by constituting the feedback loop of constant voltage supply control by a constant voltage control circuit and an existing current mirror. CONSTITUTION:A differential amplifier OP1 in a constant voltage control circuit 5 detects a voltage drop v1 of a low pass filter 4 generated by a current i1 flowing to a resistor R1 and a transistor (TR) ThQ1 and controls a current i2 so as to make the voltage v2 caused by the current i2 flowing to TRs Q3, Q2 and a resistor R2 equal to the voltage v1. Then a voltage drop of the lowpass filter 4 is subjected to voltage/current conversion and fed back to the input of a current mirror A1 to realize the constant voltage feeding characteristic. Since the feedback loop of constant voltage feeding control is constituted by the constant voltage control circuit 5 and the current mirror A1, the circuit acts by a low voltage system and low power consumption is attained.