Patent Document ID: 4680429
Application ID: 06819949
Patent Status: 1

Claim One:
1. A touch panel device for determining the touch location at which a touch sensing surface of the device is touched comprising: signal generator means for producing an alternating-current voltage output; transformer means having a primary winding means connected to the signal generator output so as to be driven by the signal generator means, the transformer means also having a secondary winding means with first and second secondary winding outputs and a center tap, the secondary winding means providing a panel scanning signal as the primary winding means is driven by the signal generator output; switching means for selectively coupling the secondary winding means to the touch sensing surface so as to selectively apply the panel scanning signal to the touch sensing surface and generate touch current signals at the center tap upon touching of the panel; and panel output signal processing means having a first input coupled to the center tap of the transformer means for receiving the touch current signals, the panel output signal processing means comprising means for determining the touch location from the touch current signals.