OPERATIONAL RECTIFIER

摘要

A current mode operational rectifier has an output terminal connectable as a DC current source of a predetermined polarity, and comprises a high gain amplifier having an inverting input terminal for receiving an input signal current from an AC current source and two alternative transmission paths for providing full wave rectification. The first transmission path includes a first transistor having its base connected to the output terminal of the amplifier and its emitter and collector connected between the output terminal of the rectifier and the input terminal of the amplifier. The first transmission path conducts DC current to the output from the input terminal of the amplifier at an instantaneous level substantially equal to the instantaneous level of the input signal when the input signal is of a first polarity. The second transmission path includes matched second and third transistors. The second transistor has its emitter and collector connected between the input and output terminals of the amplifier while the emitter and collector of the third transistor are connected between the output terminal of the amplifier and the output terminal of the rectifier. The second transistor conducts the input signal from the input terminal of the amplifier to the output terminal of the amplifier and the third transistor simultaneously conducts current to the output from the output of the amplifier at an instantaneous level substantially equal to the instantaneous level of the input signal when the input signal is of a polarity opposite that of the first polarity.