Position-Sensing and Force Detection Panel
Disclosed is a touch position sensor. Force detection circuitry can be included with the position sensor, for example, to determine an amount of force applied to a touch panel of the sensor.
1 .- 17 . (canceled)
18 . A sensor, comprising:
a voltage driver operable to provide an alternating voltage;
an integrator circuit;
a first variable resistance element coupled to a first output of the voltage driver and an input of the integrator circuit, wherein the integrator circuit is operable to measure a parameter of the first variable resistance element over a period of time; and
circuitry operable to determine, based on the measured parameter, an amount of force applied to a touch sensing panel.
19 . The sensor of claim 18 , wherein the parameter is current flowing through the variable resistance element.
20 . The sensor of claim 18 , further comprising a bias resistance element connected in parallel with the first variable resistance element.
21 . The sensor of claim 18 , further comprising a limiting resistance element connected in series with the first variable resistance element,
22 . The sensor of claim 18 , further comprising a second variable resistance element coupled with a second output of the voltage driver and the input of the integrator circuit.
23 . The sensor of claim 22 , further comprising a bias resistance element connected in parallel with the second variable resistance element.
24 . The sensor of claim 22 , further comprising a limiting resistance element connected in series with the second variable resistance element.
25 . The sensor of claim 18 , wherein the first input of the integrator circuit is at a voltage between a first voltage and a second voltage of the alternating voltage provided by the voltage driver.
26 . The sensor of claim 18 , wherein the circuitry is operable to determine an amount of force applied to the sensor using a differential measurement.
27 . The sensor of claim 18 , wherein the circuitry is further operable to determine a location in a sensing area of the touch sensing panel associated with the determined amount of force.
28 . A circuit, comprising:
a voltage driver operable to provide an alternating voltage:
an integrator circuit;
a first resistive force sensitive element coupled to a first output of the voltage driver;
a first bias resistance element connected in parallel with the first resistive force sensitive element; and
a first limiting resistance element connected in series with the first resistive force sensitive element and the first bias resistance element, and coupled to an input of the integrator circuit.
29 . The circuit of claim 38 , further comprising:
a second resistive force sensitive resistance element coupled to a second output of the voltage driver;
a second bias resistance element connected in parallel with the second resistive force sensitive element; and
a second limiting resistance element connected in series with the second resistive force sensitive element and the second bias resistance element, and coupled to the input of the integrator circuit.