Communication-Line Power Supply Control for Low-Dark-Current ECUs

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Solution Overview

Problem

Existing ECU activation methods result in significant dark current consumption due to power supply ICs monitoring communication states, especially in systems with numerous sub-ECUs, leading to battery drain.

Innovation Solution

An electronic module design that includes a power supply control circuit and switch circuits connected via a communication line, allowing power supply control through voltage fluctuations, eliminating the need for continuous power to power supply ICs when the module is off.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the power supply IC continuously monitors the communication state on the communication line, then the ECU can be activated reliably, but dark current flows continuously causing battery wear

Engineering Contradiction:

ImproveECU activation reliabilityVSAvoiddark current consumption

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The power supply IC operates in periodic cycles, alternating between active monitoring mode and low-power sleep mode. The control circuit periodically wakes the power supply IC to check communication line status, then returns it to sleep mode, thereby reducing continuous dark current consumption while maintaining activation reliability.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system dynamically adjusts the operating state of the power supply IC based on actual needs. The control circuit monitors system activation requirements and dynamically switches the power supply IC between fully active, partial monitoring, and sleep states, optimizing the balance between reliability and energy consumption.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If the number of sub-ECUs increases to handle more sensors, then the system functionality improves, but the number of ignition signal lines and wires increases

Engineering Contradiction:

Improvesystem functionalityVSAvoidnumber of wires

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The communication line serves multiple functions: it acts as both the data communication bus and the activation signal line for the power supply IC. This multi-functionality eliminates the need for separate ignition signal lines, reducing wire count while supporting multiple sub-ECUs with enhanced system functionality.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the activation signal function with the communication line function. By combining these two previously separate functions into a single communication line, the system reduces the number of required wires while maintaining the ability to activate multiple sub-ECUs and support expanded sensor connectivity.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS12602100B2Electronic module with communication-line controlled power supply for reducing dark current

Publication Date: 2026.04.14 ASTEMO LTD

AI summary

To achieve an electronic module capable of reducing dark current, which is current flowing when the electronic module is turned off, and contributing to prevention of battery wear of a vehicle or the like. Therefore, the electronic module connected to a first electronic module via a communication line includes: a microcomputer; a power supply IC that supplies power to the microcomputer; a power supply control circuit that supplies power from a battery power supply to the power supply IC; a control line connected to the communication line; and a first switch circuit that connects the control line and the power supply control circuit.