Single-Inductor Multiple-Output Converter for Vehicle Safety

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Solution Overview

Problem

Conventional DC-DC converters for vehicle safety devices are complex, bulky, and expensive due to multiple inductor coils, and shared inductor converters suffer from slowness and voltage fluctuations when multiple converters are activated simultaneously.

Innovation Solution

A DC-DC converter design that shares a single inductor between multiple converter circuits, utilizing a switch controller to manage energy distribution between them, allowing simultaneous high and low voltage outputs with reduced complexity and cost, and improved electromagnetic compliance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple inductor coils are used in each converter, then each converter can operate independently and reliably, but the circuit becomes complex, bulky, and expensive to manufacture

Engineering Contradiction:
Improveconverter operation reliabilityVSAvoidcircuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple converter circuits share a single common inductor instead of each converter having its own dedicated inductor. This merging of the magnetic energy storage component reduces the total number of components, simplifies the circuit structure, decreases size and cost, while maintaining the ability of each converter to operate independently through proper switching control

Inventive Principle:
Principle #5Merging (Combining)

2Device complexity

If a single inductor is shared by multiple voltage converters, then the circuit complexity and size are reduced, but the converters become slow and experience voltage fluctuations when multiple converters are activated simultaneously

Engineering Contradiction:
Improvecircuit complexityVSAvoidconverter response speed
Core Design Contradiction:
Device complexityVSSpeed

Solution Approach 1:

The converter circuits operate in periodic switching cycles with the shared inductor being sequentially or simultaneously energized and de-energized in a controlled manner. This periodic switching allows multiple converters to share the inductor's energy storage capacity while maintaining fast response times and stable output voltages through synchronized control

Inventive Principle:
Principle #19Periodic action

3Ease of manufacture

If a single inductor is shared by multiple voltage converters, then the manufacturing cost is reduced, but the converters become slow and experience voltage fluctuations when multiple converters are activated simultaneously

Engineering Contradiction:
Improvemanufacturing costVSAvoidoutput voltage stability
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The converter circuits incorporate control mechanisms that monitor output voltages and switching states, adjusting the switching timing and duration to maintain stable output voltages despite multiple converters sharing the common inductor. This feedback control prevents voltage fluctuations and ensures reliable operation while benefiting from the cost savings of component reduction

Inventive Principle:
Principle #23Feedback

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 solution results in a more compact, efficient, and cost-effective converter that operates faster with minimal voltage fluctuations and improved electromagnetic compliance, ensuring reliable power supply to vehicle safety devices.

Implementation Method 1

an inductor which is energised during each cycle of operation of the DC-DC converter, wherein the first converter circuit comprises: a voltage raise switch connected in parallel after the inductor

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a high voltage output capacitor connected in parallel at the output of the first converter circuit

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP2262086B1Single-inductor multiple-output converter
Publication Date: 2014.03.05 AUTOLIV DEV AB
  • EP2262086B1 patent drawingFigure 1
  • EP2262086B1 patent drawingFigure 2
  • EP2262086B1 patent drawingFigure 3

AI summary

A DC-DC converter (4) for use as a power supply for a safety device for use in a vehicle. The DC-DC converter (4) incorporates a first converter circuit (6) and a second converter circuit (7). The converter circuits (6,7) share an inductor (L). The first converter circuit (6) is configured to output a first voltage (VHigh) which is higher than the input voltage (Vin) and, simultaneously, the second converter circuit (7) is configured to output a second voltage (VLow1) which is lower or higher than the input voltage (Vin).