Patent ID: 11934612
Assignee: SYNAPTICS INCORPORATED
Field: Computer technology (Electrical engineering)
Classification: CPC G | IPC G

Claim 9:
10. A system, comprising:
a display; and
an input device coupled to the display comprising:
a plurality of electrodes disposed in a sensing region of the input device, and
a sensing circuit coupled to a first electrode and configured to detect an input object proximate the sensing region, the sensing circuit comprising:
an amplifier comprising:
an inverting input coupled to the first electrode,
a non-inverting input coupled to a drive signal, and
an output generating a resulting signal,

a feedback capacitor coupled between the output of the amplifier and the inverting input of the amplifier, and
a plurality of mixers configured to receive the resulting signal from the output of the amplifier and to generate a plurality of output signals,
wherein at least one output signal of the plurality of output signals is selected based on a comparison of a signal to noise ratio of each of the plurality of output signals with a noise threshold, the at least one output signal being selected according to the following criteria:
(a) based on none of the plurality of output signals being greater than the noise threshold, selecting each of the plurality of output signals,
(b) based on less than all the plurality of output signals being greater than the noise threshold, selecting one or more of the output signals that are less than the noise threshold,
(c) based on all of the plurality of output signals being greater than the noise threshold, selecting an output signal having a lowest noise level,

wherein the input object is detected using the selected at least one output signal,
wherein the drive signal comprises a first sinusoidal signal having a first operating frequency and a second sinusoidal signal having a second operating frequency, and
wherein the resulting signal is determined by the feedback capacitor and a capacitance of the first electrode and the resulting signal generates a sensing signal on the first electrode.