基于TDC的一种微小电容高精度测量系统设计

摘要

针对电容原理传感器中对微小电容的测量要求，利用Pcap Φ2芯片具有的高精度计时能力，设计了一个基于时间－数字转换的微小电容高精度测量系统。详细阐述了整个测量系统的实现原理和软硬件设计方法，给出了内部和外部寄生电容的补偿方法，并提出了一个适用于大多电容传感器设计的一个外围电路较为简单的高集成度单芯片解决方案。%For weak signal capacitance measurement of the capacitance sensors , a new small capacitance and high precision measurement system based on Time-Digital Conversion principle using the high precision time measurement ability of Pcap Φ2 was designed .And the principle and design method of the software and hardware to achieve the purpose of the measurement system was described in detail ,and the compensation method of the internal and external parasitic capacitance was presented .And a simple chip solution with high integration level was put forward which is suitable for most of the capacitance sensor research and develop -ment .