Texas Instruments Incorporated
Extended sensing multi-touch system

Abstract:

A capacitive touch sensing device, with: (i) a logical array of capacitive buttons have a number R of rows and a number C of columns; (ii) a first node coupled to a first column in the number C of columns, the first node for receiving a first transmit voltage; (iii) a second node coupled to a second column in the number C of columns, the second node for receiving a second transmit voltage; (iv) a number of intermediate nodes between the first node and the second node, wherein each intermediate node is coupled to a respective column in the number C of columns; and (v) circuitry for applying a respective different voltage to each of the intermediate nodes in response to the first transmit voltage and the second transmit voltage.