To eliminate the need for sensing resistor by connecting directly one transistor(TR) of two TR differential pairs coupled with a stationary current source to an input terminal of a current mirror and connecting an output terminal of the current mirror to a pass TR of a voltage regulator.

A TR 62 acts like a fixed current source with respect to a differential pair. Thus, a fixed current flowing via the TR 62 is supplied by a TR 60 or 68 or their combination. Since a base of the TR 60 is kept at a constant voltage, an output of an amplifier 74 controls a current flowing via the TR 68 to control current flowing via TRs 66 and 80. Thus, the current via the TR 80 is limited by a product between a current of a low current source and a ratio of the current mirror consisting of the TRs 66, 80.