一种带有斩波调制的带隙基准源设计

Design of a Bandgap Reference Source with Chopper Modulation

为了降低失调电压和噪声对传统带隙基准的影响,采用SMIC 40 nm CMOS工艺,提出一种低温漂、低噪声、高精度的电压型带隙基准。对温度系数调制电阻和输出分压电阻采用电阻矩阵修调,减小工艺对温度系数和带隙基准电压的影响;采用斩波调制与低通滤波器结合,大幅减小失调电压和噪声对基准电压的影响。使用Cadence Spectre工具进行仿真,当电源电压为3.3 V时,典型条件下该基准源在-40~125℃的温度范围内输出电压的温度系数为5.87×10^(-6)/℃,加入斩波电路后,噪声相较普通带隙基准显著降低,且相对精度提高了50倍。

To reduce the impact of offset voltage and noise on traditional bandgap references,a low temperature drift,low noise,high-precision voltage bandgap reference is proposed using SMIC 40 nm CMOS process.Temperature coefficient modulation resistors and output voltage divider resistors are trimmed using resistor matrices to minimize the process impact on temperature coefficient and bandgap reference voltage.Chopper modulation combined with a low-pass filter is employed to significantly reduce the influence of offset voltage and noise on the reference voltage.Simulation using Cadence Spectre tools shows that with a 3.3 V power supply under typical conditions,the temperature coefficient of the output voltage is 5.87×10^(-6)/℃over a temperature range of-40℃to 125℃.After incorporating the chopper circuit,noise is significantly reduced compared to ordinary bandgap references,and relative accuracy is improved by 50 times.