Bandgap voltage reference source based on chopper modulation technology
LI Long-d · The Internet of Things · 2014
In order to eliminate the infl uence of random offset caused by the transistor mismatch on the precision of the bandgap voltage reference source, a bandgap voltage reference source which adopts the chopper modulation technology is proposed. The symmetrical OTA structure is used in the bandgap reference voltage source to reduce its system offset. The current source in direct proportion to PTAT in the bandgap core circuit is used to provide adaptive bias for OTA and reduce the power consumption of the entire circuit. Based on 0.35μm CMOS process, the circuit was simulated with Cadence Spectre tool. The results show that the reference voltage output is 1.232 V at room temperature(27 ℃) and the supply voltage range of bandgap reference is 1.4~3 V when the chopping frequency is 100 KHz, the temperature coeffi cient in the range of -40 ℃~125 ℃ is 24.6 ppm/℃ when the voltage is 3 V.