DYNAMIC SWITCHING OF POWER MODES FOR TOUCH SCREENS USING FORCE TOUCH

摘要

Switching of power modes for touch screens is disclosed. In example embodiments a touch detect mode may be activated for touchscreen operation. The touchscreen may be a projected capacitance screen that includes force sensing based on piezo electric sensors. The touch detect mode may be a low power mode in which at least one channel, but fewer than all channels of the touch screen are monitored. When is determined that a touch event has occurred a switch to a scan mode for touchscreen operation may be performed. Scan mode may be a higher power mode in which all channels of the touch screen are scanned at least for position sensing. The touch detect mode monitoring may be implemented by monitoring the total charge on the at least one channel and providing a voltage signal. When the voltage signal meets predetermined criteria an indication of a touch event may be generated.