A novel low voltage Subtracting BandGap Reference with temperature coefficient of 2.2 ppm/°

A novel structure of CMOS low voltage bandgap reference, called "Subtracting BandGap Reference" (SBGR), is proposed. In this work, the extremely small temperature coefficient is obtained by subtracting two Complementary To Absolute Temperature (CTAT) currents with same temperature coefficient but different magnitude. The subtraction of two CTAT currents which have similar characteristics leads to low temperature coefficient. Simulation results show that the new SBGR circuit achieves a temperature coefficient three times lower than that of the conventional low voltage bandgap reference.