Error compensated current mirror

摘要

An error compensated current mirror includes a current mirror circuit having an input transistor and an output transistor; a bias current source in series with the input transistor and a load current source in series with said output transistor; the load current source including a load current source transistor in series with a load current source impedance; an input terminal connected between the bias current source and the input transistor; a buffer circuit including a transistor having its base connected between the load current source and the output transistor; a buffer biasing current source connected in series with the buffer circuit, the buffer biasing current source including a buffer biasing current source transistor in series with a buffer biasing current source impedance; said buffer biasing current source transistor being a replica device of the output transistor; an output terminal connected between the buffer circuit and the buffer biasing current source; and a compensating circuit including a compensator transistor having its base tied to the base of the buffer biasing current source transistor, its emitter connected between the buffer transistor and the buffer biasing current source impedance and its collector connected between the load current source impedance and the load current source transistor for driving the load current source to supply a current to the output transistor which is matched to that demanded by the buffer biasing current source transistor.