Pixel sensing circuit, system and electronic device for fingerprint recognition

Abstract

The invention is applicable to the technical field of fingerprint identification and provides a pixel sensing circuit. The pixel sensing circuit is in the fingerprint recognition mode or the noise detection mode, including: a capacitive sensing layer; a plurality of shielding layers, including a first type of shielding layer and a second type of shielding layer, and the second type of shielding layer is coupled to the ground terminal; The charging circuit, coupled to the capacitive sensing layer and the first shielding layer, includes a positive voltage generator for providing a positive voltage. When in fingerprint recognition mode, the charging circuit periodically provides positive voltage to the capacitive sensing layer and the first type of shielding layer. A type of shielding layer, when in the noise detection mode, the charging circuit disconnects the connection between the positive voltage generator and the capacitive sensing layer and the first type of shielding layer, and the charging circuit periodically outputs the voltage of the capacitive sensing layer to the first output end. The invention integrates the noise detection function into the pixel sensing circuit for fingerprint identification, so that it can be operated in the fingerprint identification mode or the noise detection mode, and improves the accuracy of fingerprint identification.

Description

technical field [0001] The invention belongs to the technical field of fingerprint identification, and in particular relates to a pixel sensing circuit, system and electronic equipment for fingerprint identification. Background technique [0002] With the rapid development of technology, more and more portable electronic devices such as mobile phones, digital cameras, tablet computers, and notebook computers have become necessary tools in people's lives. Because portable electronic devices are generally used by individuals and have a certain degree of privacy, the data stored in them, such as address books, photos, personal data, etc., are privately owned. Once the electronic device is lost, the information may be used by others, causing unnecessary losses. Although there is currently a password protection method to prevent the electronic device from being used by others, the password is easy to leak or be cracked, and has low security. Moreover, the user needs to remember...

AI Technical Summary

Problems solved by technology

In the prior art, for the pixel sensing circuit used in fingerprint identification, if it is desired to detect noises of different frequencies, the clock signal (also called the clock signal) of the pixel sensing circuit needs to be changed, and when When different pixel sensing circuits detect noises of different frequencies, different pixel sensing circuits need to be connected to different clock signals, resulting in difficulties in circuit implementation

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