Pulse-Switched Noise Suppression Circuit for Clean DC Reference
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Solution Overview
Problem
Noise amplification in touch-panel driver circuits due to noise accompanying the DC reference voltage, which deteriorates the signal-to-noise ratio (SNR) of the amplified response signal.
Innovation Solution
A noise suppression circuit comprising a switch unit, a capacitor, and an analog front-end unit with an operational amplifier, where the switch unit is controlled by a pulse signal to isolate and ground high-frequency noises in the DC reference voltage, thereby reducing noise amplification during signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a DC reference voltage is used in the operational amplifier, then the operational amplifier can function properly, but noise accompanies the DC reference voltage which is amplified and deteriorates the signal-to-noise ratio
Solution Approach 1:
The reference voltage signal path is segmented into two separate paths: one path generates the DC reference voltage with noise that is discarded, and another path generates a clean reference voltage without noise. This segmentation allows the operational amplifier to receive a noise-free reference voltage while maintaining proper functionality.
Solution Approach 2:
The noise component is extracted and removed from the reference voltage signal. The circuit separates the noisy DC reference voltage from the clean reference voltage needed by the operational amplifier, taking out only the useful low-frequency reference signal while eliminating the high-frequency noise components.
2Object-affected harmful factors
If noise filtering is applied to the response signal, then some noise is reduced, but the complexity of the analog front-end unit increases
Solution Approach 1:
Noise suppression is performed in advance on the reference voltage signal before it reaches the operational amplifier. By pre-filtering the reference voltage to remove noise components, the circuit avoids the need for additional complex noise filtering stages in the signal path, thereby reducing overall device complexity while still achieving noise reduction.
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
Effectively suppresses noise in the DC reference voltage, improving the signal-to-noise ratio (SNR) by isolating high-frequency noise components and preventing additional noise introduction during the operational amplifier's operation, enhancing the overall performance of touch-panel driver circuits.
Implementation Method 1
a capacitor having a first terminal connected to the first terminal of the switch unit and a second terminal grounded
Data Source
AI summary
This disclosure provides a noise suppression circuit for suppressing a noise in a voltage signal. The noise suppression circuit comprises: a switch unit having a first terminal receiving the voltage signal and a second terminal; a capacitor having a first terminal connected to the first terminal of the switch unit and a second terminal grounded; and an analog front-end unit including an operational amplifier with a signal input terminal and a reference-voltage input terminal electrically connected to the second terminal of the switch unit; wherein the switch unit is controlled by a pulse signal.