SOI高温压力传感器专用集成电路设计

针对压力传感系统高温条件下无法稳定工作、性能下降等问题,设计了一种基于SOI CMOS高温工艺的压力传感器专用集成电路(ASIC),主要由零温度系数恒流源、仪表运算放大器(由恒定跨导运放组成)和零温度系数电压基准组成,具有为压力传感器供电、放大输出信号及调节零点的功能,重点介绍了零温度系数恒流源、仪表运放及组成仪表运放的运算放大器等相关电路。仿真结果表明,-55~225℃温度范围内,恒流源温度系数为109ppm/℃,运算放大器输入MOS管跨导几乎与温度无关,仪表运放输入输出电压成正比且共模抑制比高达125 d B。测试结果显示该压力传感器专用集成电路可在225℃下正常工作。

Design of SOI high temperature application specific integrated circuit for pressure sensor

Aiming at unstable working and performance reduction at high temperature of pressure sensing system, a pressure sensing application specific integrated circuit (ASIC) was designed based on high temperature SOI CMOS process, which mainly consists of zero-temperature coefficient constant current source, instrument operational amplifier consisting of constant transconductance amplifier and zero-temperature coefficient voltage reference, for supplying for pressure sensor, amplifying the output signal and adjusting zero point. The zero-temperature coefficient constant current source, instrument amplifier and its related circuit are mainly introduced. Simulation result shows that, the application specific integrated circuit can work properly in the temperature range of -55 to 225 ℃, with temperature coefficient of constant current source of 109 ppm/℃, temperature independence of the MOS transconductance of amplifier biasing circuit , output voltage proportional to input voltage in the instrument amplifier and CMRR up to 125 dB. The test result shows that the pressure sensor ASIC can work properly at 225 ℃.