CMOS SHUNT REGULATOR WITH BANDGAP REFERENCE FOR AUTOMOTIVE ENVIRONMENT

A temperature-stable shunt regulator for automotive environments using standard digital CMOS technology is described. The new technique empl oyed to implement the bandgap reference cell reduces the influence of the high offset input voltages present in the CMOS op-amps and allows for a simple and cost-effective design of a nontrimmed chip with good temperature characteristics. The shunt regulator operates from battery voltages as low as 6 V and withstands voltage peaks up to 120 V. The regulated output voltage (5.15 V) presents a temperature coefficient o f 140 ppm/degrees-C in the -15 to +105-degrees-C temperature range. Th e shunt regulator was integrated in a custom automotive CMOS digital c hip and occupies 0.53 mm2.