Capacitive Coupling Circuit With Ground Feedback for Noise Suppression
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Solution Overview
Problem
Conventional capacitive coupling circuit devices require additional noise suppression components, which increase mounting area and cost, and cause signal delays and distortions due to limited noise suppression effectiveness.
Innovation Solution
A capacitive coupling circuit device incorporating a ground-side feedback circuit with a series connection of a second capacitor to a parallel circuit of a first capacitor and a resistor, reducing noise without adding components on the signal line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a capacitor is used to connect the ground on the signal input side to the ground on the signal output side, then some noise suppression effect is obtained, but the noise suppression effectiveness is limited and additional noise filter components are required
Solution Approach 1:
The patent applies feedback by connecting the ground terminals of both signal input side and signal output side through a feedback circuit comprising capacitors and resistors. This feedback mechanism provides a controlled return path for noise currents, enabling effective noise suppression without requiring additional filter components on the signal line.
Solution Approach 2:
The patent introduces an intermediary feedback circuit as a mediator between the ground terminals. This intermediary circuit, composed of capacitors C1-C3 and resistors R1-R2, acts as a bridge that suppresses conducted and radiated noise while maintaining signal integrity, eliminating the need for direct noise filter components on the signal path.
2Object-affected harmful factors
If noise filter components are added to further suppress noise, then noise suppression effectiveness is improved, but mounting area and cost increase
Solution Approach 1:
The patent merges the noise suppression function with the existing ground connection structure. By integrating capacitors and resistors in a feedback configuration between ground terminals, the invention combines multiple functions (noise suppression, ground reference, signal isolation) into a single circuit arrangement, eliminating the need for separate noise filter components and reducing overall mounting area.
Solution Approach 2:
The feedback circuit comprising capacitors C1-C3 and resistors R1-R2 serves multiple functions simultaneously: it suppresses conducted noise, reduces radiated noise, maintains ground potential stability, and preserves signal transmission. This multi-functionality eliminates the need for dedicated noise filter components, reducing both mounting area and component count.
3Object-affected harmful factors
If noise filter components are added to further suppress noise, then noise suppression effectiveness is improved, but signal delays and distortions occur
Solution Approach 1:
The feedback circuit provides a controlled path for noise currents while maintaining the integrity of the signal transmission path. By using capacitors and resistors in a feedback configuration between ground terminals, the circuit suppresses noise without introducing the signal delays and distortions that would result from adding filter components directly to the signal line.
Solution Approach 2:
The patent segments the noise suppression function from the signal transmission function. Noise suppression is achieved through the feedback circuit connected between ground terminals, while the signal line remains clear of additional components. This segmentation prevents signal delays and distortions while maintaining effective noise suppression.
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
This configuration effectively reduces conducted and radiated noise, minimizing component count, area, and cost while improving signal quality.
Implementation Method 1
In capacitive coupling isolators, the signal input side and the signal output side are coupled by a capacitor. The capacitor insulates the DC component and transmits the high-frequency component
Implementation Method 2
The ground-side feedback circuit is inserted between a ground terminal on a signal input side and a ground terminal on a signal output side of the capacitive coupling circuit
Data Source
AI summary
A capacitive coupling circuit device is provided with a capacitive coupling circuit and a ground-side feedback circuit. The capacitive coupling circuit demodulates a modulated signal, which is obtained by modulating an input signal and transmitting a modulated input signal through a coupling capacitor. The ground-side feedback circuit is inserted between a first ground terminal on a signal input side of the capacitive coupling circuit and a second ground terminal on a signal output side of the capacitive coupling circuit. The ground-side feedback circuit is configured by connecting a second capacitor in series to a parallel circuit of a first capacitor and a first resistor. Alternatively, the ground-side feedback circuit may be configured by connecting the second capacitor and a third capacitor in series to both ends of the parallel circuit of the first capacitor and the first resistor, respectively.