Texas Instruments Corporation

Wendy Xiaowen Fang

Ing-Yih James Wang

A 5-wire touch screen system includes a touch screen () including a wiper () and a resistive layer () aligned with the wiper and first (UL), second (UR), third (LR), and fourth (LL) resistive layer contacts, wherein a touch on the screen presses a small portion of the wiper against the resistive layer, producing a touch resistance (R) between them at a touch point on the resistive layer. The wiper and various contacts are selectively coupled to first (V) and second (GND) reference voltages, respectively, to generate an analog touch voltage (V) at the touch point. The wiper and various contacts are selectively coupled to an analog input () and a reference voltage input of an ADC () for converting the touch voltage (V) to a digital representation. Analog voltages (V) and (V) at the touch point are converted to corresponding digital representations by the ADC.

5-wire resistive touch screen pressure measurement circuit and method

Various apparatuses, methods and systems for detecting simultaneous touches at multiple locates are disclosed herein. For example, some embodiments provide an apparatus for detecting a touch, the apparatus including a resistive touch screen and a controller connected to the touch screen. The touch screen includes a number of electrically conductive columns and rows. In various embodiments, the touch screen is an analog matrix, with the overlapping columns and rows forming a matrix of cubics that can each detect one touch at a time, and with the location of the touch detectable in an analog fashion within each cubic. The resolution of the analog matrix in these embodiments is thus higher than that of the columns and rows. The controller includes an analog to digital converter switchably and sequentially connected to each of the columns and rows. The controller also includes a voltage source switchably and sequentially connected to each of the columns and rows. The controller is adapted to connect the voltage source to one of the rows when the analog to digital converter is sequentially connected to each of the columns and to connect the voltage source to one of the columns when the analog to digital converter is sequentially connected to each of the rows.

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Murphy, TX, United States of America

Wendy Xiaowen Fang