Differential Receiver Circuit With Common-Mode Noise Compensation
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Solution Overview
Problem
In electric vehicles and hybrid electric vehicles, differential communication between voltage measurement devices is prone to failure due to common mode noise, especially when cascode-coupled current input stages are used, leading to signal attenuation and incorrect current direction, which affects the reliability of battery cell voltage measurement.
Innovation Solution
A communication circuit with a receiver circuit that employs two transmission paths with signals in opposite phases, utilizing first and second compensation circuits to detect and compensate for current attenuation caused by common mode noise, ensuring adequate signal levels by adding detected attenuation currents to each other.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If differential communication is used between voltage measurement devices operating at different potentials, then communication reliability should improve, but common mode noise from motor rotation causes signal attenuation and communication failure
Solution Approach 1:
The patent converts the harmful common mode noise into a useful signal by detecting the noise-induced current attenuation and adding compensatory current in the opposite phase. The compensation circuit uses the same differential transmission paths to inject compensating current that counteracts the noise effect, transforming the noise problem into a solvable signal processing task that maintains communication reliability
Solution Approach 2:
The patent implements feedback by detecting the actual current attenuation caused by common mode noise and using this detection to generate compensatory current. The compensation circuit continuously monitors the differential signals and adjusts the compensating current accordingly, creating a closed-loop system that actively counteracts noise effects and maintains stable communication
2Speed
If cascode-coupled current input stages are used to increase communication speed, then data transmission rate improves, but current attenuation occurs when common mode noise is superimposed
Solution Approach 1:
The patent applies preliminary anti-action by proactively injecting compensating current in opposite phase before the noise-induced attenuation can completely degrade the signal. The compensation circuit is designed to preemptively counteract the expected noise effects on the cascode-coupled current input stages, maintaining signal integrity while preserving the high-speed communication capability
3Use of energy by moving object
If communication current is reduced to suppress heat generation and battery discharge, then energy consumption decreases, but communication failure occurs due to susceptibility to common mode noise
Solution Approach 1:
The patent introduces an intermediary compensation circuit that mediates between the low-current differential communication signals and the common mode noise interference. This intermediary circuit detects the noise effects and injects compensating current, enabling reliable communication at reduced current levels without direct exposure to noise, thus achieving low energy consumption with maintained reliability
Data Source
AI summary
A communication circuit includes a receiver circuit that provides differential communication by using first and second transmission paths which transmit first and second signals. The receiver circuit includes a compensation circuit that compensates for the attenuation of a current when common mode noise is superimposed on the first signal and on the second signal. The compensation circuit includes a first compensation circuit and a second compensation circuit. The first compensation circuit detects an electric current attenuation of the first signal when the common mode noise is superimposed thereon, and compensates for the attenuation thereof by adding the detected electric current attenuation to the second signal. The second compensation circuit detects an electric current attenuation of the second signal when the common mode noise is superimposed thereon, and compensates for the attenuation thereof by adding the detected electric current attenuation to the first signal.