基于CMOS的电容-电压转换电路的设计

摘要

在MEMS传感器的电容检测电路中,经常要采用电容—电压转换电路.本研究将两相不交叠时钟模块应用到设计中,使得该电路用单个时钟就能进行有效控制,并能够满足MEMS电容检测系统的要求.采用0.25 μm工艺库对电路进行优化并给定了电路仿真的相应结论.仿真结果表明,其CMOS运放部分的增益为77.76 dB,单位增益带宽为5.60 MHz,相位裕量为65.87°,输出摆幅为-2.0～1.89 V,输入共模范围为-1.0 ～1.93V,正摆率为+9.92 V·μs-1,负摆率为5.03 V·μs-,功耗为1.03 mW.该电路适合于pF量级范围内的电容变化,该变化范围为35～1 200 pF,且输出线性度良好.%In the MEMS sensor capacitance detection of circuit,capacitive-voltage conversion circuit is often used.Two phase non-overlapping clock module has been applied to the design,so the circuit can be effectively controlled by a single clock and also be satisfied to the requirements of MEMS capacitive detection system.Using 0.25 μm technology library to optimize the circuit,the appropriate conclusions have been given out to the circuit simulation.The results show that part of its CMOS opamp is gain of 77.76 dB,the bandwidth of unity gain is 5.60 MHz,the phase margin is 65.87°,the output swing is-2.0 ～ 1.89 V,the input common mode range is-1.0 ～ 1.93 V,the positive slew rate is 9.92 V · μ S-1,the negative slew rate is 5.03 V · μ s-1,the power consumption is 1.03 mW.The circuit is suitable for capacitance change in the order of pF within the range of 35 ～ 1 200 pF,and the output is in good linearity.