Vehicle Load Switching Circuit for Low Quiescent Current

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Solution Overview

Problem

Existing motor vehicle control devices cannot effectively reduce quiescent current consumption for both temporarily and permanently required functions, as they often need to remain connected to the vehicle electrical system, limiting the ability to disconnect loads and thus conserve battery charge, especially for components without energy-saving modes.

Innovation Solution

A motor vehicle control device with an electronic switching element and control unit that allows for switch-on and switch-off functionality of loads, using a resistor and current control means to generate a predefinable voltage difference for consistent and controlled switching, independent of vehicle electrical system voltage, and a second supply voltage path for uninterrupted power to direct loads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If control devices are completely disconnected from the vehicle electrical system to reduce quiescent current, then energy consumption is reduced, but control functions that must be permanently available (e.g., steering angle determination) cannot be provided

Engineering Contradiction:

Improvequiescent current consumptionVSAvoidavailability of control functions

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent divides the control device into two separate control units: a first control unit that remains permanently connected to the vehicle battery for essential functions (steering angle determination), and a second control unit that can be completely disconnected to reduce quiescent current. This segmentation allows the system to maintain necessary control functions while minimizing energy consumption during idle periods.

Inventive Principle:

Principle #1Segmentation

2Reliability

If control devices remain permanently connected to the vehicle battery to provide continuous control functions, then reliability is improved, but quiescent current consumption increases

Engineering Contradiction:

Improveavailability of control functionsVSAvoidquiescent current consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The control device is segmented into two independent control units with distinct power supply paths. The first control unit remains permanently connected for essential functions, while the second control unit is disconnected during idle periods. This allows the system to maintain reliability for critical functions while minimizing overall energy consumption.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different parts of the control device have different connectivity states: the first control unit maintains permanent connection for reliability, while the second control unit is disconnected for energy savings. This local differentiation of connectivity quality optimizes both reliability and energy consumption.

Inventive Principle:

Principle #3Local quality

3Use of energy by moving object

If individual loads are switched off to reduce current consumption, then energy efficiency is improved, but the ability to quickly restore full functionality is reduced

Engineering Contradiction:

Improvecurrent consumptionVSAvoidswitching response time

Core Design Contradiction:

Use of energy by moving objectVSSpeed

Solution Approach 1:

The electronic switching element is kept in a ready state with control circuitry prepared to immediately restore power to loads when needed. The switching mechanism is pre-configured so that transition from switched-off to on state occurs rapidly, minimizing response time while maintaining energy savings during idle periods.

Inventive Principle:

Principle #10Preliminary action

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 minimizes current consumption by temporarily disconnecting non-essential loads from the supply voltage, reducing quiescent current consumption, especially when the ignition is switched off, while ensuring continuous power to essential loads, thus extending battery life and improving system efficiency.

Implementation Method 1

an electronic switching element for arrangement in a supply voltage path of the load and a control unit for controlling the electronic switching element

Methodology Applied

Scientific EffectElectrical switching: Electrical Resistance

Implementation Method 2

using a resistor and current control means to generate a predefinable voltage difference for consistent and controlled switching

Methodology Applied

Scientific EffectOhm's law voltage generation: Ohm's Law

Data Source

PatentUS11909254B2Motor vehicle control device having a switch-on and switch-off function for at least one electrical consumer that is to be controlled by the motor vehicle control device

Publication Date: 2024.02.20 THYSSENKRUPP PRESTA AG

AI summary

A motor vehicle control device may have a switch-on and switch-off function for at least one electrical load to be controlled by the motor vehicle control device. The motor vehicle control device may include an electronic switching element for arrangement in a supply voltage path of the electrical load and a control unit for controlling the electronic switching element. The control unit is designed to provide a control signal for switching the electronic switching element based on at least one input signal. The control unit may include a resistor connected to the supply voltage path and a current control means connected in series therewith for generating a predefinable voltage difference at the resistor as the control signal for the electronic switching element.