Sensing Circuit with Symmetric Grounding for EMI Protection
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Solution Overview
Problem
Increasing processor power consumption and signal frequency lead to electromagnetic interference that affects the performance of sensitive electrical equipment, causing malfunctions and poor performance in environments with changing magnetic fields.
Innovation Solution
A sensing circuit with electromagnetic interference protection is designed, featuring a computing element and a sensing module connected through symmetric first and second circuits, grounding the signal input terminal and grounding terminal of the computing element and sensing module to suppress interference effects, maintaining normal sensing and computing functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If additional electromagnetic shielding layers or shells are implemented, then electromagnetic interference protection is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts the harmful common-mode voltage from the signal path by introducing a differential amplifier that converts the single-ended signal with interference into a differential signal, separating the useful signal from the electromagnetic interference and eliminating the need for complex shielding structures
Solution Approach 2:
The patent introduces a differential amplifier as an intermediary device between the sensing module and the output, which acts as a mediator to reject common-mode electromagnetic interference while preserving the differential signal, thereby providing EMI protection without adding shielding layers
2Object-affected harmful factors
If grounding is performed at multiple points, then electromagnetic interference protection is improved, but circuit complexity increases
Solution Approach 1:
The patent applies equipotentiality by connecting both the positive and negative power supply terminals to the same ground point, ensuring they are at the same potential and preventing ground loops, while the differential amplifier maintains balanced potentials on its input terminals to reject common-mode interference
3Productivity
If processor frequency and power consumption are increased, then computing performance is improved, but electromagnetic interference generated increases
Solution Approach 1:
The patent converts the harmful electromagnetic interference into a beneficial differential signal by using the differential amplifier to detect the voltage difference between its input terminals, where the interference appears as common-mode voltage that is rejected, while the useful signal appears as differential voltage that is amplified
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 sensing circuit effectively reduces electromagnetic interference impact on measurements, improving accuracy and reducing false-positive warnings by grounding the terminals close to the computing element, thus ensuring reliable operation in high-frequency magnetic fields.
Implementation Method 1
When a current flows through a wire, a circular magnetic field is formed around it. When a large current starts to change, a large magnetic field change is generated. A changing current generates a changing magnetic field, a changing magnetic field generates a changing electric field, and a changing electric field generates a changing magnetic field again.
Data Source
AI summary
A sensing circuit with electromagnetic interference protection function comprises a computing element and a sensing module. The computing element has a first terminal and a second terminal, and is configured to output a sensing result according to a voltage difference between the first terminal and the second terminal. The sensing module has a first connection point, a second connection point, a third connection point and a fourth connection point. The first connection point is electrically connected to the first terminal, the second connection point is electrically connected to the second terminal and grounded through a first circuit, the third connection point is electrically connected to the first connection point and is configured to receive an electrical signal, and the fourth connection point is electrically connected to the second connection point and grounded through a second circuit, wherein the first circuit is the same as the second circuit.