Based on the principle of TDC, a weak capacitance measurement circuit for MEMS capacitive pressure sensors was proposed in this paper. Taking STM32 F103 as the main controller, the circuit conducted the timing control of Pcap01 through SP1 bus to complete the collection, analysis, processing and display of the capacitance data. The circuit had the characteristics including small volume, strong anti-interference ability, high resolution and high update rate. Measurements of static capacitance below 10 pF and MEMS capacitive pressure sensor showed that the circuit had a good performance with resolution of 61 aF and 16 bits of effective precision at a refresh rate of 10 Hz.%基于TDC原理文中提出了一种用于MEMS电容式压力传感器的微弱电容测量电路.该电路以微处理器STM32F103为控制核心, 通过SPI总线对Pcap01芯片进行时序控制, 完成电容数据的采集、分析、处理和显示.该电路具有体积小、抗干扰性强、分辨率高和刷新频率高的特点.通过对10 pF以下的固定电容和MEMS电容式压力传感器测量验证新电路的性能.实验结果表明, 电路在10 Hz刷新频率下有效精度位为16位, 分辨率可达61 aF.
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