适用于高精度ADC的高精度低噪声基准源

High Accuracy and Low Noise Bandgap Reference for High Precision ADC

提出了一种适用于高精度ADC的高精度低噪声CMOS带隙基准电路结构,通过一路恒流源作用在二极管来实现高阶曲率补偿技术,改善了传统基准电路结构在全温区电压温度系数大的问题。对于放大器的随机失配电压造成的输出电压漂移问题,采用斩波技术消除。该结构采用了TSMC 0.18μm工艺,在5 V电源电压下工作,功耗在典型条件下为1.2 mW,电路面积为0.245 mm^(2)。测试结果显示,通过一次室温修调后,在-40℃到85℃温度区间电路的温度系数可以达到1.2×10^(-6)/℃。

A CMOS Bandgap reference circuit of high accuracy and low noise is presented,which is suitable for high precision ADC.In the bandgap circuit proposed,a constant current source is applied on the diode to achieve high-order curvature correction.The output voltage offset caused by the mismatch of the operational-amplifier is eliminated through chopping technique.This circuit,implemented in TSMC 0.18μm process,consumes a power of 1.2 mW under room temperature from 5 V supply voltage and occupies an area of 0.245 mm^(2).Ex-perimental results shows that the temperature coefficient of the circuit is only 1.2×10^(-6)/℃in the temperature range of-40℃to 85℃just through one single room temperature trim.