自互一体式电容触摸屏检测电路设计

A self-cap and mutual-cap detection circuit for capacitive touch panel

为结合自、互电容检测方式各自的优点,提出了自互一体式的电容触摸屏检测电路.在研究自、互电容检测的基础上,设计可通过软件配置的自互一体式电容检测电路模块,结合前端检测电路的放大电路的优化设计,提高检测抗干扰的能力,降低系统的功耗.通过仿真和测试实验验证了自互一体式电容触摸屏检测电路的有效性,该检测电路方案已成功应用于集创北方的ICNT87系列触控芯片,具有高灵敏度,支持真实多点,获得了更好的触控效果.

Both the self capacitance （sel^cap） and mutual-capacitance （mutual-cap） projected ca pacitive touch （PCT） techniques have pros and cons： the former has stronger signals than the lat- ter while the latter allows multi-touch detection. In this article, a 2-in-1 capacitance detection cir cuit is designed that can be configured to either the self cap detection mode or the mutual-cap de- tection mode. Furthermore, comparing with the conventional preamplifier, the optimized pream- plifier of the design consumes less power and has better anti-noise performance, both of which are validated by the simulation and experimental studies. The proposed circuit has been in mass production of Chipone ICNT87 series ICs. Through the proposed design, the circuit has the ad- vantages of high sensitivity and true multi-touch support, with a better performance.