Study And Implementation Of Adaptive Scan Control Circuits Used In Capacitive Touch Panel

Capacitive touch panel has wildly used in mobile phone. It has promoted the development of touch technology. To adapt the development of capacitive touch panel, touch panel controller must have higher sensitivity, stronger anti-noise capability, multi-touch and lower power consumption. Scan control circuit plays an important role in the touch panel controller. It controls the scanning of the whole chip, including scan touch panel, receive and store scan data. Scan control circuit affects the performance of touch panel controller.This master’s degree thesis firstly study the system architecture and control principle of touch panel controller based on analyzes the basic principles of capacitive touch panel, then discuss the synchronous technology, low power technology and DFT (Design for Testability) technology. Finally an adaptive scan controller is designed for capacitive touch panel controller, including a reset circuit module, a clock circuit module, a register module, a data receiving module, a data processing module, a data storge module and a scan control module.Focusing on the stability and performance of the system, reset circuit module uses synchronous technology, clock circuit module uses switching technology, data storage module and scan control module use parallel operation. Finally RTL (Register Transfer Level) code is presented and simulation is executed. The results show that scan control logic can correctly scan the touch panel and get scan data, scan touch panel and store scan data can operate at the same time.Compile results show that adaptive scan controller can achieve test operation and power consumption is reduced21.9%compare to previous design. The adaptive scan controller designed in this thesis is correct and feasible according to the above results.