Capacitive Touch Sensing Circuit with Dynamic Charge Dissipation
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Solution Overview
Problem
1-bit sigma delta capacitive touch sensing circuits face challenges in achieving high resolution and large detectable range while detecting capacitance variations, as they provide constant charge dissipation, leading to inefficiencies.
Innovation Solution
A capacitive touch sensing circuit incorporating a switching capacitor integrating circuit, encoding circuit, and feedback circuit that dynamically adjusts charge dissipation based on encoded results, allowing for enhanced sensing resolution and detectable range by modifying the charge dissipation path according to encoded signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If constant charge dissipation is provided in the feedback circuit, then the circuit structure is simple, but the sensing resolution and detectable range cannot be simultaneously guaranteed
Solution Approach 1:
The patent applies dynamics by making the charge dissipation path adjustable rather than fixed. The feedback circuit dynamically changes its charge dissipation capability based on the encoded result from the capacitive touch unit, allowing the system to adapt to different sensing requirements and achieve both high resolution and large detectable range.
Solution Approach 2:
The patent changes the parameter of charge dissipation ability in the feedback circuit. By adjusting the charge dissipation path according to the encoded result, the system can modify its electrical characteristics to simultaneously achieve high sensing resolution and large detectable range, resolving the contradiction between these two parameters.
2Ease of manufacture
If constant charge dissipation is provided in the feedback circuit, then the circuit is easy to implement, but the detectable range is limited
Solution Approach 1:
The feedback circuit transitions from a static constant charge dissipation design to a dynamic adjustable design. The charge dissipation path is modified based on the encoded result, enabling the circuit to adapt to different capacitance variations and achieve a large detectable range while maintaining ease of implementation through systematic control.
Solution Approach 2:
The patent implements feedback by using the encoded result from the capacitive touch unit to control the charge dissipation path in the feedback circuit. This closed-loop control allows the system to automatically adjust its characteristics based on the detected signal, expanding the detectable range without complicating the overall circuit implementation.
3Stability of the object's composition
If constant charge dissipation is provided, then the circuit is stable, but minor capacitance variations cannot be detected with significant transfer capacitance
Solution Approach 1:
The patent makes the charge dissipation path dynamic rather than static. By adjusting the charge dissipation ability according to the encoded result, the circuit can maintain stability during normal operation while being able to detect minor capacitance variations when needed, resolving the contradiction between stability and detection precision.
Solution Approach 2:
The system changes the charge dissipation parameter dynamically based on operating conditions. This allows the circuit to maintain stable operation under normal conditions while being able to sensitively detect minor capacitance variations by adjusting the charge dissipation path, thus achieving both stability and high measurement precision.
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 capacitive touch sensing circuit effectively increases sensitivity and detectable range by dynamically adjusting charge dissipation, enabling detection of minor capacitance variations even with significant transfer capacitance, thus meeting requirements for high resolution and large detectable range.
Implementation Method 1
The switching capacitor integrating circuit is coupled to a to-be-tested capacitive touch unit that receives an input signal, and the switching capacitor integrating circuit integrates the input signal to generate an output signal
Implementation Method 2
The feedback circuit is coupled to the switching capacitor integrating circuit and the encoding circuit and provides the switching capacitor integrating circuit with a charge dissipation path for discharging charges from the switching capacitor integrating circuit
Data Source
AI summary
A touch apparatus, a capacitive touch sensing circuit of the touch apparatus, and a touch sensing method are provided. The capacitive touch sensing circuit includes a switching capacitor integrating circuit, an encoding circuit, a feedback circuit, and a decoding circuit. The switching capacitor integrating circuit receives an input signal and integrates the input signal to generate an output signal. The encoding circuit receives and encodes the output signal to generate an encoded result. The feedback circuit provides a charge dissipation path for discharging charges from the switching capacitor integrating circuit, and the feedback circuit receives the encoded result and adjusts a charge dissipation ability provided by the charge dissipation path according to the encoded result. The decoding circuit receives and decodes the output signal to generate a touch detecting result.