Touch Detection Circuit With Frequency-Grouped Signal Generators

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Solution Overview

Problem

Touch detection circuits in thin electronic devices are susceptible to noise interference due to the proximity of touch panels and display panels, which degrades signal-to-noise ratio (SNR) and affects performance.

Innovation Solution

The touch detection circuit divides driving signal generators into groups, each generating signals with distinct frequencies, reducing low-frequency noise interference by optimizing signal generation and processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the touch detection circuit uses traditional single-frequency driving signals, then the circuit structure is simple, but the signal-to-noise ratio is low and noise interference is severe

Engineering Contradiction:

Improvesignal-to-noise ratioVSAvoidcircuit structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the driving signal generators into multiple groups, where each group generates driving signals at different frequencies. This segmentation allows the system to differentiate between touch signals and noise through frequency discrimination, thereby improving the signal-to-noise ratio while maintaining manageable circuit complexity through modular organization.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the frequency parameter of driving signals by using multiple frequency groups. By assigning different frequencies to different signal types (touch signals versus noise), the system can selectively filter and process signals based on their frequency characteristics, effectively improving measurement precision without requiring complex additional hardware.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If the touch detection circuit uses high-frequency driving signals, then the signal-to-noise ratio improves, but the time required for touch sensing operation increases

Engineering Contradiction:

Improvesignal-to-noise ratioVSAvoidtouch sensing operation time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent employs periodic switching between different frequency groups of driving signals. By alternately activating different frequency groups in a periodic manner, the system can process multiple frequency bands within a single touch sensing operation cycle, thereby improving signal-to-noise ratio through frequency differentiation without proportionally increasing the total operation time.

Inventive Principle:

Principle #19Periodic action

3Power

If the driving signal swings between positive and negative voltage with large amplitude, then the signal strength is strong, but low-frequency noise interference increases

Engineering Contradiction:

Improvesignal strengthVSAvoidlow-frequency noise interference

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12422952B2Touch detection circuit

Publication Date: 2025.09.23 HIMAX TECH LTD

AI summary

A touch detection circuit includes a plurality of driving signal generators. The driving signal generators are divided into a plurality of driving signal generator groups, and each of the driving signal generator groups comprises at least one of the driving signal generators. The driving signal generators respectively generate a plurality of driving signals, and a frequency of each of the driving signals in one of the driving signal generator groups is different from a frequency of each of the driving signals in another one of the driving signal generator groups.