Constant current circuit using a current mirror circuit and its application

摘要

A current mirror circuit includes an input transistor and an output transistor. A first bipolar transistor has a collector terminal connected to a predetermined reference portion of a current supply path of a power source and an emitter terminal connected to a collector terminal of the output transistor for absorbing an electrical potential difference between the reference portion and the collector terminal of the output transistor. A second bipolar transistor has a base terminal connected to the emitter terminal of the first bipolar transistor and a collector terminal connected to a base terminal of the first bipolar transistor for fixing an electrical potential of the collector terminal of the output transistor to a base-emitter voltage of the second bipolar transistor.