In-Vehicle Filter Device Steady Current Suppression Circuit

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Solution Overview

Problem

The conventional in-vehicle CAN FD communication system experiences signal quality degradation and increased power consumption due to DC current flow through resistors, which affects data transmission and reception.

Innovation Solution

A data transmission and reception device with a filter device that attenuates noise and a steady current suppression circuit, using a capacitor or switch element to facilitate transient currents, reducing DC current flow and maintaining signal quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a resistor is connected between the communication lines to remove noise due to reflection, then signal quality is improved, but power consumption increases due to DC current flow

Engineering Contradiction:
Improvesignal qualityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent changes the electrical parameter of the filter device from a resistive configuration to a capacitive configuration. By using a capacitor instead of a resistor, the filter device can attenuate noise due to reflection while blocking DC current, thereby reducing power consumption while maintaining signal quality.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent substitutes the resistive filtering mechanism with a capacitive filtering mechanism. The capacitor-based filter device replaces the resistor-based approach, utilizing the different electrical characteristics of capacitors to achieve both noise attenuation and DC current blocking functions.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If communication speed is increased to 2 Mbps in the data phase, then data transmission efficiency is improved, but noise due to reflection increases affecting signal quality

Engineering Contradiction:
Improvedata transmission efficiencyVSAvoidsignal quality
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent introduces a capacitor as an intermediary element in the filter device. This capacitor acts as a mediator that allows the high-speed data transmission to proceed while simultaneously filtering out noise due to reflection, thus enabling both high productivity and maintained signal quality.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If a filter device is added to remove noise due to reflection, then signal quality is improved, but device complexity increases

Engineering Contradiction:
Improvesignal qualityVSAvoidcircuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts only the essential filtering function needed to handle noise due to reflection, implementing it through a simple capacitor-based circuit. By taking out only the necessary filtering capability rather than adding complex filtering systems, the patent improves signal quality while minimizing the increase in device complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

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 solution reduces power consumption while maintaining signal quality by suppressing steady currents and facilitating transient currents, thereby improving data transmission and reception in in-vehicle networks.

Implementation Method 1

a steady current suppression circuit that suppresses a steady current flowing through the filter device and facilitates a transient current flowing through the filter device

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3435607B1In-vehicle processing device and in-vehicle system
Publication Date: 2020.07.29 HITACHI AUTOMOTIVE SYST LTD
  • EP3435607B1 patent drawingFigure 1~2
  • EP3435607B1 patent drawingFigure 3~4

AI summary

The present invention provides an in-vehicle processing device and an in-vehicle system capable of reducing power consumption while suppressing quality degradation of data to be transmitted and received. An ECU (100A) includes a data transmission and reception device (20A) for transmitting and receiving data and an MPU (10) for controlling the data transmission and reception device (20A). The data transmission and reception device (20A) includes a filter device (FD) and a steady current suppression circuit (113A). The filter device (FD) attenuates noise that is superimposed on data by reflection of the data. The steady current suppression circuit (113A) suppresses a steady current flowing through the filter device (FD) and facilitates a transient current flowing through the filter device (FD).