Current source device for D=A converter

摘要

The current source device has a current source supplying a pair of exclusive=OR parallel transistors (S1,S2). The current source comprises a regulated cascade stage (P1,P2,P3,N1). The first transistor (P1) is controlled by a bias voltage (B1) and the control input of the second transistor (P2) is coupled to the output of a regulating transistor (P3).The control input of the latter is coupled to a junction (K1) between the first two transistors. The cascade transistors and the regulating transistors are of p-channel type, the parallel transistors being of n-channel type.