Abstract:
Touch-screen controllers, particularly those in mobile telephones, are prone to erratic behavior when the mobile telephone is plugged into devices, such as AC power adapters, that create electrical noise. To more intelligently mitigate noise in these and other electronic devices that include capacitive touch-screen displays, the present inventors devised, among other things, a touch-screen controller that measures noise level in the touch-screen display and increases its drive voltage only when necessary to exceed the measured noise level, thereby reducing the chance of noise signals being misinterpreted as touch events while also reducing power consumption over prior techniques. Moreover, for electronic devices that include radio receivers, intelligently increasing the touch-screen voltages based on measured noise, avoids the sensitivity-reduction (desense) issues that providing constant higher operating voltage creates.