Differential touch detection circuit and touch judgment method adopting the differential touch detection circuit

Abstract

The invention provides a differential touch detection circuit and a touch judgment method adopting the differential touch detection circuit. The differential touch detection circuit comprises a firstchannel circuit, a second channel circuit, a differential operational amplifier and an analog-to-digital converter, and the first channel circuit and the second channel circuit have the same connection structure. Wherein the first channel circuit corresponds to a first channel, and the first parasitic capacitor Cx1 is coupled with the first channel circuit through the first touch sensor TK1; the first channel circuit is coupled to a negative input end voltage VIN and a positive output end voltage VOP of the differential operational amplifier. The second channel circuit corresponds to a secondchannel, and a second parasitic capacitor Cx2 is coupled with the second channel circuit through a second touch sensor TK2; the second channel circuit is coupled to the positive electrode input end voltage VIP and the positive electrode output end voltage VON of the differential operational amplifier. Wherein two input ends of the analog-to-digital converter are respectively coupled with the VOP and the VON, and the output Vout of the analog-to-digital converter is the difference between the VOP and the VON.

Description

technical field [0001] The invention relates to touch detection technology. Background technique [0002] In a traditional touch system, it is usually judged whether a key is pressed according to the output result of the change of the charging time of the parasitic capacitance. Since the parasitic capacitance is easily affected by power interference and electromagnetic interference during the entire charging process, the output result is easy to introduce this part of interference, thereby affecting the final judgment result of the button, resulting in false triggering or missed detection of the button. [0003] Therefore, there is an urgent need for a touch circuit with high anti-interference and a touch judgment method. Contents of the invention [0004] In order to solve the problems in the prior art, the present invention provides a differential touch detection circuit and a touch judgment method using the differential touch detection circuit. [0005] The differenti...

AI Technical Summary

Problems solved by technology

Since the parasitic capacitance is easily affected by power interference, electromagnetic interference, etc. during the entire charging process, the output result is easy to introduce this part of interference, thereby affecting the final judgment result of the key, resulting in false triggering or missed detection of the key.

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