Parallel Booster Circuit Isolation for Load Driving Reliability

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Solution Overview

Problem

Existing load driving devices with parallel booster circuits face challenges in continuing boosting operations when components like capacitors fail, leading to potential engine stoppages due to insufficient valve opening energy, as they are not effectively protected against heat and current fluctuations, and fail to isolate failed circuits.

Innovation Solution

A load driving device with multiple booster circuits connected in parallel, equipped with current cutoff circuits at upper and lower stages, and a calculation device to detect failures and adjust current settings, allowing normal circuits to continue operations by isolating failed ones.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple booster circuits are connected in parallel to increase charging speed, then the boosting operation can be maintained, but when any component fails, all circuits may fail together causing engine stoppage

Engineering Contradiction:
Improvecharging speedVSAvoidsystem reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent divides the booster circuit system into independent modular units, each with its own current cutoff switch. This segmentation allows individual circuits to be isolated from failures in other circuits, preventing system-wide collapse while maintaining overall functionality through remaining healthy modules.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The current cutoff switch acts as an intermediary protective element between the power supply and each booster circuit. When a failure is detected, this intermediary component automatically interrupts the current flow to the failed circuit, preventing the failure from propagating to other circuits while allowing healthy circuits to continue operating.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If current cutoff switches are provided in upper stage only (as in PTL 1), then MOSFET failures can be isolated, but failures of other components like diodes or capacitors cannot be electrically separated

Engineering Contradiction:
Improvefailure isolation capabilityVSAvoidcircuit configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the current cutoff capability into multiple independent switches positioned at different stages of the circuit. By placing current cutoff switches at both upper and lower stages, the system creates multiple isolation points that can handle failures of various component types, not just MOSFETs.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different current cutoff switches are strategically positioned at different locations (upper stage and lower stage) with specific functions tailored to their positions. This local differentiation allows each switch to handle specific failure modes appropriate to its location, providing comprehensive protection without unnecessary complexity.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If electrolytic capacitors are used in booster circuits, then the circuits can function properly, but the capacitors have short lifespans due to weakness against heat and current fluctuation

Engineering Contradiction:
Improvecircuit functionalityVSAvoidcapacitor lifespan
Core Design Contradiction:
Ease of operationVSDuration of action of stationary object

Solution Approach 1:

The patent implements protective measures in advance by equipping each capacitor with dedicated current cutoff switches at both upper and lower stages. This beforehand cushioning prevents excessive current and heat from damaging the capacitors, thereby extending their operational lifespan while maintaining their necessary functionality.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The control device continuously monitors the status of each booster circuit and provides feedback to the current cutoff switches. When abnormal conditions such as excessive current or temperature are detected, the feedback mechanism triggers the appropriate cutoff switches to protect the capacitors from further damage, thereby extending their service life.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4645662A1Load driving device and method for controlling load driving device
Publication Date: 2025.11.05 ASTEMO LTD
  • EP4645662A1 patent drawingFigure 1
  • EP4645662A1 patent drawingFigure 2
  • EP4645662A1 patent drawingFigure 3

AI summary

Provided is a highly reliable load driving device including a plurality of booster circuits connected in parallel, where even when some booster circuits fail while protecting components of the booster circuits, another normal booster circuit can continue the boosting operation. A load driving device includes a first booster circuit; a second booster circuit connected in parallel to the first booster circuit; a first current cutoff circuit disposed on an upper stage side of the first booster circuit; a second current cutoff circuit disposed on a lower stage side of the first booster circuit; a third current cutoff circuit disposed on an upper stage side of the second booster circuit; a fourth current cutoff circuit disposed on a lower stage side of the second booster circuit; and a calculation device configured to calculate a control command for controlling the first booster circuit and the second booster circuit, in which when a failure of the first booster circuit is detected, the calculation device causes the first current causes circuit to cut off a current from a power supply to the first booster circuit, and changes a current set value of the second booster circuit to be lower than that before the failure to operate the second booster circuit.