一种基于BCD工艺的宽压-宽温电流基准电路

A Wide Voltage-Wide Temperature Range Current Reference Circuit Based on BCD Process

设计了一种基于BCD工艺的宽压-宽温电流基准电路。利用片上多晶硅电阻的温度系数受工艺影响较小的特点,选定其为基准电流定义单元。分析片上电阻温度特性,并设计与其温度系数相等的参考电压,加载到电阻上,从而实现了温度系数很低的基准电流。分析了高温下三极管寄生元件漏电现象,通过添加补偿管,提高了基准电流在高温下的稳定性。电流基准基于0.35μm BCD工艺设计。仿真结果表明,在6.5~36 V电源电压、-55℃~125℃内,输出电流为250μA,温度系数为9.3×10^(-6)/℃,受电源变化导致的电流变化量小于62 nA。

This paper presented a current reference in wide voltage and temperature range based on BCD technology. Based on the feature that the TC of the on-chip poly-silicon resistor was process-insensitive, the on-chip resistor was set as the reference current defining element. First, the temperature characteristic of the on-chip resistor was analyzed, and a reference voltage whose TC was equal to the resistor’s was designed and applied on the resistor. Then, a reference current with a very low TC could be achieved. The leakage phenomenon of the parasitic element of the triode under high temperature was analyzed, and the stability of the reference current under high temperature was improved by adding a compensation transistor. This CS was based on 0.35 μm BCD process. Simulation results showed that the output current was 250 μA and the TC was 9.3×10^(-6)/℃ within 6.5~36 V supply voltage and-55 ℃~125 ℃. The amount of current change caused by the power supply was less than 62 nA.