Two CMOS Bandgap Reference Circuits
Guican Chen · Microelectronics & Computer · 2003
Two types of CMOS bandgap reference circuits are presented in this paper.Based on the conventional bandgap reference,a low voltage cascode current mirror is used to produce bias currents and hence the errors resulted from the effect of the channel length modulation of PMOS are reduced.The bias voltage of the cascade current mirror is provided by an op -amp and hence the bandgap voltages are of supply independent.One of them is also able to decrease the effect of the op -amp offset by using dual diodes in serial to increaseΔV BE .The simulation results show that the output of the bandgap voltages are1.228±0.003V and1.215±0.003V respectively over the process,voltage and temperature variations,the temperature coefficient are only33.7ppm/℃and34.1ppm/℃respectively,the supply voltage has little influence on the output reference while it is above2v and2.8v;the dissipation of the circuits are less than0.1mW and0.34mW respectively,with the3.3v supply.