面向MEMS加速度传感器的仪表放大器的设计与实现

Design and Realization of Instrument Amplifier for MEMS Acceleration Sensor

摘要:

加速度传感器已经广泛应用于军事、工业、环境监测等领域,已经成为热点的研究对象,但是器件的小型化与可靠性成为限制该技术发展的重要瓶颈;因此,针对新型硅基MEMS 加速度传感器的信号处理电路小型化的问题,提出了一种与MEMS技术完全兼容基于CMOS工艺的片上集成运算放大器电路;通过提取分析相关加速度传感器的性能参数,设计低功耗、低噪声且符合精度等特殊要求的前置放大器;同时对集成仪表放大器的主要电路特性和功耗进行了仿真分析;从仿真结果看,设计的三运放仪表放大器的关键参数—共模抑制比可以到达101 dB,整体性能良好;完成了对仿真结果的版图设计和验证,继而在华润上华0.5 μm CMOS标准工艺线上进行了流片,完成了芯片的封装测试,该测试结果显示运放的增益能够达到42 dB,功耗仅为5.25 mW,符合预期的设计目标。

Abstract:

Acceleration sensor has been widely used in military, industrial, environmental monitoring and other fields, which has become a hot research object, But the miniaturization and reliability of the device becomes an important bottleneck to limit the development of the technology. Therefore, downsizing the signal processing circuit for a novel silicon based MEMS accelerometer, This paper presents an on-chip integrated operational amplifier circuit based on CMOS, which is fully compatible with MEMS. A preamplifier with low power consumption, low noise and accuracy is designed by extracting the performance parameters of the relevant acceleration sensor. At the same time, the main circuit characteristics and power consumption of the integrated instrumentation amplifier are simulated and analyzed. From the results, the design of the three-amplifier instrumentation amplifier key parameters - common mode rejection ratio can reach 101dB, the overall performance is good. Completed the simulation results of the layout design and verification. And then in the CSMC 0.5 μm CMOS standard process line on the film, completed the chip packaging test.The test results show that the op amp's gain can reach 42 dB, power consumption is only 5.25 mW, in line with the expected design goals.