Circuit combining bipolar transistor and JFET{3 s to produce a constant voltage characteristic

A pair of FET's are coupled in series between the emitter and collector of a bipolar transistor and the juncture of the FET's coupled to the bipolar transistor base. The FET gates are coupled to the bipolar transistor collector. When a current is passed through the emitter-collector terminals in excess of a threshold value, a constant voltage will appear over a substantial current range. The constant voltage is related to FET Vp and can be used to compensate or track integrated circuits that contain both FET's and bipolar transistors.