新型16位模/数转换器AD7715的应用数字电压表的设计

Design of Appliyed Digital Voltmeter of New 16 Bits A/D Convertor

AD7715是美国Analog-Devices公司生产的高精度模/数转换芯片,片内含有可编程增益放大器、可编程数字滤波器和寄存器,采用Σ-Δ转换技术实现16位的精确测量。本电压表采用89C55单片机作为控制器,采用模拟开关进行多级切换对被测电压经过信号调理,采用新型16位模/数转换器AD7715对调理后的被测电压进行采样,采用128X64点阵式液晶显示屏作为显示器,实现波形和汉字显示。本文简明地介绍了应用AD7715芯片进行高精度电压表设计的方法。

AD7715 is a kind of high accuracy A/D convertor chip manufactured by America Analog-Devices Company. There are programmable plus amplifier, programmable digital filter and register in this chip. It adopts the Σ-Δ convert technology to realize the 16 bits accurate measurement. This voltmeter takes 89C55 SCM as control unit and adopts analog switch to adjust the voltage signals that will be measured by multilevel switching. Also it uses new 16 bits A/D convertor AD7715 to sample the voltage to be measured after it has been adjusted. Meanwhile the liquid crystal display with 12864 lattice is chosen as the display to show the wave figure as well as Chinese characters. This paper introduces briefly the method to design the high accuracy voltmeter based in the application of AD7715.