基于CH372的USB虚拟交流电压表的设计与实现

为了实现对交流电压进行安全、精确测量,设计实现了基于USB总线接口芯片CH372的虚拟交流电压表。系统以CH372芯片和单片机STC11F08XE构成USB控制通信模块,以精密电阻、仪用放大器AD620、继电器及真有效值转换器AD637组成精密调理电路,采用VB6．0设计了友好的应用界面,实现了对交流电压的自动、手动量程的控制与测量。实验表明：该虚拟交流电压表的测量准确度达到了预定的误差要求。该设计在基于USB接口的虚拟多用表的设计和应用上具有一定的指导意义。

Design and implementation of virtual AC voltage meter based on USB bus interface chip CH372

In order to measure AC voltage safely and accurately, an virtual AC voltage meter based on the USB bus interface chip CH372 was designed and implemented. Control and communication module was composed of CH372 chip and MCU STC11F08XE. Signal condition circuit was composed of resistor, instrumentation amplifier AD620, relay and the true RMS converter AD637. A friendly user interface was designed based on VB6. 0. It implemented automatic and manual high-accuracy measurement on the AC voltage. Experimental results showed.. The measurement accuracy of the virtual AC voltage meter achieved the expected error. It might afford benefit for designing and application of virtual multimeter based on USB bus interface.