电容触摸屏驱动电路的设计

The Design of a Capacitive Touch Screen Driving Circuit

电容触摸屏是目前被普遍使用的人机交互设备,文章介绍了一种电容触摸屏驱动电路的设计。电路中包括一块触摸控制芯片FPGA、9个八选一多路选择器、9个运算放大器与开关组成的电荷转移法检测电路和9个十位ADC(模拟数字转换器),可以实现71个通道的信号并行收发传输。其中一个八选一多路选择器、一个运算放大器与开关组成的电荷转移法检测电路和一个ADC组成一路信号接收的基本单元。9路基本单元并行,将触摸屏上传输来的模拟信号转换为FPGA可识别的数字量进行处理,结合算法最终确定触摸坐标点。

Capacitive touch screen is a widely used man-machine interaction device at present.This paper introduces the design of a capacitive touch screen drive circuit.The circuit includes a main control chip FPGA,nine eight-choice multiplex selectors,charge transfer detection circuit consisting of nine Operational amplifier and switch,and nine ten-place ADCs(analog-digital converter),which can realize the parallel transceiver and transmission of signals over 71 channels.An eight-choice multiplex selector,a charge transfer detection circuit consisting of an operational amplifier and a switch,and an ADC constitute the basic unit of a one-way signal reception.The 9-channel basic unit is parallel,the analog signal transmitted on the touch screen is converted into digital quantity recognized by FPGA for processing,and the touch coordinate point is finally determined by combining with the algorithm.