A 99% Current Efficient Three-Transistor Regulator With Built-In 80 ppm/degrees C Reference, for 0-10 mA Loads

We present a regulator made of three transistors with a built-in temperature compensated voltage reference with a measured coefficient of 80 ppm/degrees C. The regulator is realized as a shunt-shunt negative feedback loop around a 2-transistor voltage reference. The regulator has a 99% current efficiency for load currents above 1 mu A. The design has been fabricated using standard 0.18-mu m CMOS technology and can drive loads upto 10 mA. Larger load currents can be supplied by increasing the size of the driving transistor. Large sizes of the driving transistor tend to reduce the feedback loop bandwidth. Measurements report a current consumption of 187 pA for the core circuit and 12.2 nA for the overall circuit including the feedback resistor. The recovery time was improved from 5 ms to 30 mu s for a transient load step of 0.35 mu A to 1.2 mA with a dI/dt > 6 mA/mu s using auxiliary circuits.