Touch Circuit Emulation Signal Amplification Range

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Solution Overview

Problem

Existing touch circuits face challenges in accurately determining finger touch points due to small capacitance variations, leading to signal amplification issues that often result in amplified sensing signals exceeding the operating voltage range.

Innovation Solution

A touch circuit comprising a detection circuit and an emulation circuit, where the emulation circuit generates an emulation signal based on a reference load to adjust the amplification range, preventing the operational signal from exceeding the voltage limits by canceling or adjusting the electrical states on the electrodes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the sensing signals are amplified to make the capacitance variation more obvious, then the touch point can be judged more accurately, but the amplified sensing signals exceed the operating voltage range

Engineering Contradiction:

Improvetouch point detection accuracyVSAvoidvoltage range violation

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The sensing signal processing is divided into two independent paths: one path processes the sensing signal through the detection circuit, while the other path generates an emulation signal through the emulation circuit. This segmentation allows each path to operate within its own voltage range while contributing to the final touch detection result.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The emulation circuit acts as an intermediary that generates a reference signal representing the electrical state without touch. This intermediary signal is then combined with the detection signal to produce the operational signal, effectively subtracting the baseline state and isolating the touch-induced capacitance change without requiring excessive amplification.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the capacitance of finger is used for touch detection, then the touch panel can detect touch events, but the small capacitance value leads to smaller level variation for sensing signals

Engineering Contradiction:

Improvetouch detection capabilityVSAvoidsignal level variation

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The emulation circuit creates a copy of the electrical state signal that represents the system state without touch. This copied signal is then used in the operational circuit to subtract the baseline electrical state from the detection signal, effectively amplifying the small capacitance variation caused by finger touch through differential measurement.

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The emulation circuit continuously generates an emulation signal that reflects the current electrical state of the touch panel. This feedback signal is fed into the operational circuit where it is combined with the detection signal, allowing the system to dynamically adapt to changing baseline conditions and maintain high detection precision.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11216113B2Touch circuit

Publication Date: 2022.01.04 XMYTH IP GRP LTD

AI summary

The present invention provides a touch circuit, which comprises a detection circuit and an emulation circuit. The detection circuit detects a detection signal; the emulation circuit includes a reference load and receives a signal. The emulation circuit generates an emulation signal according to the reference load and the signal. The touch circuit outputs a touch signal according to the detection signal and the emulation signal.