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提出了一种改善电流比例失调的无电阻带隙基准电压源。该电路将传统源耦差分对结构的电压转换器改进为共源共栅结构电流镜,并引入了一对额外的电流镜来钳制漂移,显著改善由沟道长度调制效应所引起的电流镜失调,同时减小了电流比例系数的温度漂移。设计了自偏置电路、启动电路以及简单二阶补偿电路,采用0.5μm BCD工艺仿真,在5 V工作电压下,输出电压有效温度系数为19.8×10–6/(℃–45~+125℃),低频电源抑制比PSRR为–50dB,工作电压在4.0~6.5 V变化时,输出电压变化小于17 mV,电路总功耗约300μW。
A resistorless bandgap reference is proposed to improve the current imbalance. This circuit improves the voltage converter of the traditional source-coupled differential pair architecture to a cascode current mirror and introduces an extra pair of current mirrors to clamp the drift and significantly improve the current mirror misalignment caused by the channel length modulation effect , While reducing the temperature drift of the current scaling factor. A self-bias circuit, a start-up circuit and a simple second-order compensation circuit are designed. Using a 0.5μm BCD process simulation, the effective temperature coefficient of the output voltage is 19.8 × 10-6 / (℃ -45 ~ + 125 ℃) ), PSRR of low-frequency power supply is -50dB. When the operating voltage changes from 4.0 to 6.5 V, the output voltage variation is less than 17 mV and the total power consumption of the circuit is about 300 μW.