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1. (WO2018035759) CAPACITANCE INTERPRETATION CIRCUIT AND FINGERPRINT RECOGNITION SYSTEM

Pub. No.:    WO/2018/035759    International Application No.:    PCT/CN2016/096587
Publication Date: Fri Mar 02 00:59:59 CET 2018 International Filing Date: Thu Aug 25 01:59:59 CEST 2016
IPC: G06K 9/00
G06F 3/044
Applicants: SHENZHEN GOODIX TECHNOLOGY CO., LTD.
深圳市汇顶科技股份有限公司
Inventors: CHAO, Kuo-Hao
赵国豪
YANG, Meng-Ta
杨孟达
Title: CAPACITANCE INTERPRETATION CIRCUIT AND FINGERPRINT RECOGNITION SYSTEM
Abstract:
A capacitance interpretation circuit (10, 20) and a fingerprint recognition system. The capacitance interpretation circuit (10, 20) includes a contact layer (100) for receiving the contact of a finger (FG); a shielding layer (102) arranged below the contact layer (100), the shielding layer (102) forming a parasitic capacitance (Cp) with the contact layer (100); a drive circuit (104, 204) coupled to the contact layer (100) and the shielding layer (102); a sensing circuit (106) electrically connected to the contact layer (100) and used for sensing a contact capacitance (Cf) at a second time; and a first switch (SW1, SW2), one end thereof being electrically connected to the shielding layer (102) and the other end thereof being electrically connected to the drive circuit (104, 204) or the contact layer (100). The capacitance interpretation circuit (10, 20) and the fingerprint recognition system can eliminate the effect of the parasitic capacitance (Cp) and improve the accuracy and efficiency of capacitance sensing or fingerprint recognition.