Design of a high precision bandgap voltage reference

As a way of generating high precision voltage reference, bandgap voltage reference is a very important module in the analog integrated circuits and mixed-signal integrated circuits to provide a temperature and power supply insensitive output voltage. The bandgap voltage reference circuit presented here in this paper is an improved conventional bandgap reference circuit. A self-biasing structure and a current mirror structure are used. It can get the PTAT(Proportional to absolute temperature) current, and then get the voltage that is proportional to temperature. The output voltage of an Op-amp is adopted as the op-amp´s offset voltage to make the power consumption lower, and high value polysilicon resistors of low temperature coefficient are used to reduce the impact of resistor drift on the circuit. The errors caused by current mismatch is eliminated in the improved CMOS bandgap, and at the same time the DC PSRR (power supply rejection ratio) is increased because of the increase of the feedback factor.