Touch Panel Driving Signal Circuit for Temperature-Stable Detection
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Solution Overview
Problem
Conventional touch panel driving signal systems are affected by temperature changes, leading to reduced detection accuracy and increased circuit area due to the need for noise resistance, which is not effectively addressed by existing solutions.
Innovation Solution
A driving signal generating system comprising a boost circuit, an amplifier, and a level shifter, with a select device that provides either an analog or digital waveform driving signal, ensuring the signal is not temperature-dependent and adaptable to environment or system requirements, thereby eliminating the need for a low-dropout regulator and reducing circuit area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a charge pump is used to provide power to the level shifter to increase the level of the driving signal to resist noise, then the noise resistance is improved, but the power provided by the charge pump is affected by temperature causing the driving signal level to change and reducing detection accuracy
Solution Approach 1:
The patent changes the power source from a charge pump (temperature-sensitive) to an LDO regulator (temperature-stable), maintaining the voltage level while eliminating temperature-induced variations. This allows the system to resist noise while maintaining stable detection accuracy across temperature changes.
Solution Approach 2:
The LDO regulator acts as an intermediary between the power supply and the level shifter, providing a stable voltage that is not affected by temperature. This intermediary component isolates the temperature sensitivity from the driving signal generation, allowing noise resistance to be maintained without sacrificing detection accuracy.
2Stability of the object's composition
If an LDO regulator is adopted to make the power provided by the charge pump less liable to temperature, then the temperature stability is improved, but the circuit area is increased
Solution Approach 1:
The patent extracts the temperature-sensitive charge pump from the power supply chain and replaces it with a compact LDO regulator. This extraction eliminates the temperature stability issue while the LDO's smaller size compared to the charge pump circuit actually reduces the overall circuit area.
3Object-affected harmful factors
If a square wave driving signal is generated using a level shifter and charge pump, then the signal level is increased to resist noise, but the signal level changes with temperature reducing detection accuracy
Solution Approach 1:
The patent changes the power source parameter from a temperature-sensitive charge pump to a temperature-stable LDO regulator, thereby stabilizing the driving signal level across temperature variations while maintaining the high signal level needed for noise resistance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system provides a stable driving signal for touch panels, enhancing detection accuracy without increasing circuit area and ensuring the signal is not affected by temperature fluctuations, thus improving touch point detection precision.
Implementation Method 1
a boost circuit 21 provides a power voltage Vb
Implementation Method 2
an amplifier 22 provides an analog waveform driving signal Va
Implementation Method 3
a level shifter 23 provides a digital waveform driving signal Vd
Data Source
AI summary
In a driving signal generating system, a boost circuit provides a power voltage, an amplifier provides an analog waveform driving signal, and a level shifter provides a digital waveform driving signal. A select device selects the analog waveform driving signal as a driving signal for a touch panel in an analog waveform mode, and selects the digital waveform driving signal as a driving signal for the touch panel in a digital waveform mode. The boost circuit provides the power voltage to the amplifier, and the amplifier, in the digital waveform mode, generates an output voltage as a power for at least one last stage of the level shifter.