CURRENT MIRROR FOR SUPPLYING CONSTANT CURRENT TO OUTPUT LOAD IMPEDANCE IN WIDE RANGE

摘要

PROBLEM TO BE SOLVED: To prevent the fluctuation of the output currents of a current mirror depending on the value of a load impedance while an output impedance is increased as much as possible in a conventional current mirror for generating constant currents. SOLUTION: The output of an arithmetic amplifier 24 is connected with each gate of pMOS transistors T3 and T4, and each input of the arithmetic amplifier 24 is connected with the drains of pMOS transistors T3 and T4. Thus, the voltages of the two transistors can be controlled, and the output currents of a current mirror can be maintained so as to be substantially constant against a load impedance in a wide range.