设计了一种线性补偿低温漂高电源抑制比带隙基准电压源电路。带隙基准核心电路采用三支路共源共栅电流镜结构, 提高电路电源抑制比。补偿电路采用分段补偿原理, 在低温阶段, 加入一段负温度系数电流, 在高温阶段, 加入一段正温度系数电流, 通过补偿, 使带隙基准输出电压的精确度大大提高, 达到降低温度系数的目的; 同时电流镜采用共源共栅结构, 不仅提高电路的电源抑制比, 而且可以抑制负载对镜像晶体管电压的影响。基于 0.5 μm CMOS工艺, 使用 Cadence Spectre对电路仿真, 结果表明, 在 -50~+125℃温度范围内, 基准输出电压的温度系数为 2.62×10-6/℃, 低频时的电源抑制比 (PSRR)高达 88 dB。

A bandgap voltage reference source circuit with piecewise-linear compensation is designed. It has the functions of a low temperature drift and a high power supply rejection ratio. The bandgap reference core circuit adopts the structure of three branches and cascode current mirror, which improves the rejection ratio of the power supply for circuit. According to the piecewise-linear compensation principle, the circuit adds a negative temperature coefficient current when the temperature is low. Similarly, the circuit adds a positive temperature coefficient current when the temperature is high. This kind of compensation circuit greatly improves the accuracy of output voltage for bandgap reference and it achieves the goal of reducing the temperature coefficient. In addition, the current mirror adopts the cascode structure, it not only improves the rejection ratio of power supply for circuit, but also suppresses the load effect on the mirror transistor voltage. Basing on 0.5 μm standard of CMOS technology, the circuit is simulated by Cadence Spectre software. The result shows that the temperature coefficient of reference output voltage is 2.62×10-6/℃ when the temperature ranges from -50 ℃ to +125 ℃, and the Power Supply Rejection Ratio(PSRR) reaches 88 dB when the circuit is under low frequency condition.