一种基于VCO量化的MEMS加速度计接口电路

采用0.18μm CMOS工艺,设计了一种基于VCO量化的电容式MEMS加速度计接口电路。电路基于VCO实现量化,可直接输出数字信号,克服了传统模拟力反馈的非线性问题,且不需要ADC或额外的比较器电路,大大降低了电路的复杂性。仿真结果表明,该接口电路系统噪声基底为18μg·Hz^-1/2,最大非线性误差为0.57%,电路功耗为6.7 mW,输入带宽和检测范围分别为2.5 kHz和±1.0 g。该接口电路达到较好的性能。

A MEMS Accelerometer Interface Circuit Based on VCO Quantization

A capacitive MEMS accelerometer interface circuit based on VCO quantization was designed in a 18μm CMOS process.The circuit realized quantization based on VCO,and could directly output digital signals,which overcame the non-linear problem of traditional analog force feedback.ADC or additional comparator circuit did not be required,which greatly reduced the complexity of the circuit.Simulation results showed that the interface circuit system had a noise floor of 18μg·Hz^-1/2,a maximum non-linear error of 0.57%.The circuit power consumption was 6.7 mW.The input bandwidth and detection range were 2.5 kHz and±1.0 g,respectively.The interface circuit achieved a better performance.