设计了一种高阶曲率补偿低温漂系数的CMOS带隙基准电压源,采用自偏置共源共栅结构,降低了电路工作的电源电压.采用电流抽取电路结构,在高温阶段抽取与温度正相关电流,低温阶段抽取与温度负相关的电流,使得电压基准源在整个工作温度范围内有多个极值点,达到降低温漂系数的目的.在0.5 μm CMOS工艺模型下,Cadence Spectre电路仿真的结果表明,在-40～+145℃范围内,温度特性得到了较大的改善,带隙基准电压源的温漂系数为7.28×10-7/℃.当电源电压为2.4V时电路就能正常工作.%A low temperature drift coefficient CMOS bandgap voltage reference source with high-order curvature compensation was designed.A self-biased cascode circuit structure was used to reduce the working supply voltage.Using the circuit structure of the current extraction,different currents were extracted at different temperatures.A positive temperature coefficient current could be extracted from its output branch in the period of high temperature;on the contrary,a negative temperature coefficient current could be extracted in the period of low temperature.In this way,the voltage reference source has multiple poles in the whole operating temperature range and the goal of lower temperature drift coefficient is achieved.Based on 0.5 μm CMOS process,the results of Cadence Spectre circuit simulation shows that the temperature characteristics are improved greatly in the temperature range of-40 ℃ to 145 ℃,and the temperature drift coefficient is 7.28 × 10-7/℃.The circuit can work properly when the power supply voltage is 2.4 V.
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