Touch detection circuit and denoising circuit thereof
AssigneePixart Imaging Inc.
InventorsShiue-Shin LIU, Chang-Yuan LIOU, Cheng-Chih CHANG
Life of this patent
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Abstract
There is provided a denoising circuit connecting to two pins of a chip. The denoising circuit includes a shielding branch, a driving branch and an intermediate capacitor. The shielding branch is connected between a first pin of the chip, a ground voltage and a shielding metal. The driving branch is connected between a second pin of the chip and a load. The intermediate capacitor is connected between the shielding branch and the driving branch. The first pin and the second pin are used to respectively output a sinusoidal signal.
Claims20
A denoising circuit, configured to be connected between two pins of a chip and a load, the denoising circuit comprising:
- a first resistor, connected between a first pin of the chip and a first node;
- a first capacitor, connected between the first node and a ground voltage;
- a second resistor, connected between a second pin of the chip and a second node;
- a second capacitor, connected between the first node and the second node;
- a third resistor, connected to the second node;
- a third capacitor, connected between the third resistor and a driving trace,
- wherein the driving trace is configured to be connected to the load;
- and
- a shielding metal, surrounding the driving trace.
A touch detection circuit, configured to detect an impedance variation of a load, the touch detection circuit comprising:
- a chip, comprising a first pin and a second pin;
- and
- a denoising circuit, connected between the chip and the load, and comprising:
- a first resistor, connected between the first pin of the chip and a first node;
- a first capacitor, connected between the first node and a ground voltage;
- a second resistor, connected between the second pin of the chip and a second node;
- a second capacitor, connected between the first node and the second node;
- a third resistor, connected to the second node;
- a third capacitor, connected between the third resistor and a driving trace,
- wherein the driving trace is configured to be connected to the load;
- and
- a shielding metal, surrounding the driving trace.
A touch detection circuit, configured to detect an impedance variation of a load, the touch detection circuit comprising:
- a chip, comprising a first pin and a second pin respectively configured to output a sinusoidal signal;
- a shielding metal;
- a shielding branch, connected between the first pin, a ground voltage and the shielding metal, and configured to direct noises to the ground voltage;
- a driving branch, connected between the second pin and the load;
- and
- an intermediate capacitor, connected between the shielding branch and the driving branch.
Dependencies are inferred from the claim text.