Title:
CAPACITANCE DETECTION CIRCUIT, AND TOUCH CHIP
Document Type and Number:
WIPO Patent Application WO/2022/016359
Kind Code:
A1
Abstract:
A capacitance detection circuit (200), capable of reducing the influence of screen noise on capacitance detection. The capacitance detection circuit (200) comprises: a drive circuit (210) connected to a first channel and a second channel in a screen, and used to charge or discharge the first channel and the second channel; a cancellation circuit (220) comprising a cancellation capacitor (Cc) connected to the first channel and used to cancel a base capacitor (Cx1) of the first channel; a release circuit (230) connected to the second channel, and used to release charges on the second channel so as to cancel self-capacitance of the second channel, such that only a noise signal from the screen is comprised in a capacitance signal of the second channel; and an amplification circuit (240) separately connected to the first channel and the second channel, and used to receive a capacitance signal of the first channel and the capacitance signal of the second channel, and to output a voltage signal according to the capacitance signal of the first channel and the capacitance signal of the second channel, wherein the voltage signal is used to determine a capacitance change quantity of self-capacitance of the first channel relative to the base capacitor after the noise signal is cancelled.
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Inventors:
YUAN GUANGKAI (CN)
Application Number:
PCT/CN2020/103215
Publication Date:
January 27, 2022
Filing Date:
July 21, 2020
Export Citation:
Assignee:
SHENZHEN GOODIX TECH CO LTD (CN)
International Classes:
H03K17/96
Foreign References:
| CN206440771U | 2017-08-25 | |||
| CN107949824A | 2018-04-20 | |||
| CN107820570A | 2018-03-20 | |||
| CN108886361A | 2018-11-23 | |||
| CN110568952A | 2019-12-13 | |||
| US9542051B2 | 2017-01-10 |
Attorney, Agent or Firm:
LONGSUN LEAD IP LTD. (CN)
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