| 摘要 |
<p>An offset compensation circuit for use in conjunction with a capacitive touch sensor in for example a tablet personal computer. The controller may have a single application specific integrated circuit (ASIC) with an output circuitry connected to a row electrode to generate timing signals that generate drive waveforms for a transparent touch screen (36) for driving a capacitive multi-touch sensor, to determine proximity of object at each node by measuring coupling of drive waveforms for reading sensor. Various noise rejection and dynamic range enhancement techniques may permit the controller to be used with various sensors in various conditions without reconfiguring hardware. The offset compensation circuit uses a programmable offset digital to analogue converter to generate a static component for the capacitive coupling and a sub-tractor circuit. The offset signal is adjustable and determined from a look-up table for each of the touch pixels.</p> |
