Low voltage, high impedance current mirrors

摘要

Low voltage, high impedance current mirrors realizable in MOS or junction transistor circuits and particularly suited for use in integrated circuits. The current mirrors use first and second transistors coupled as a differential pair with a tail current that may be part of the input current to be mirrored. Another component of the input current to be mirrored is applied to the drain/collector of the first transistor of the differential pair, with the gate/base of that transistor being coupled to a bias voltage. The voltage on the drain/collector of the first transistor is effectively inverted and used to control the gate/base of the second transistor to provide a drain/collector current in the second transistor equal to the difference between the tail current and the current in the drain/collector of the first transistor. Various embodiments are disclosed.