Load Drive Apparatus Failsafe Circuit for Vehicle Lighting
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Solution Overview
Problem
Existing load drive apparatuses for vehicle lighting systems require additional load drive elements as backups, increasing cost and complexity when integrated with control circuits, as they need to handle large currents and ensure fail-safe operations.
Innovation Solution
A load drive apparatus with independently placed first and second drive elements, a control circuit, and a failsafe circuit with abnormality detection, which controls both drive elements to drive loads without a dedicated backup element, ensuring operation even when an abnormality occurs in the control or power supply circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a backup load drive element is included to ensure fail-safe operation, then reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent divides the drive system into independently placed first and second drive elements, each capable of driving respective loads. This segmentation allows the system to maintain functionality by redistributing drive responsibilities when one element fails, eliminating the need for a separate backup element while ensuring fail-safe operation.
Solution Approach 2:
Each drive element is designed to potentially drive multiple loads (headlights and tail lamps), creating a universal drive capability. When one drive element becomes abnormal, the other can take over its driving responsibilities, making the system self-sufficient without requiring dedicated backup components.
2Reliability
If multiple load drive circuits are provided for large current handling, then reliability is improved, but cost increases
Solution Approach 1:
The patent merges the backup drive functionality into the existing first and second drive elements rather than adding separate backup circuits. The abnormality detection unit monitors these existing elements, and when abnormality is detected, the system automatically redistributes driving tasks among the same components, achieving backup capability without additional manufacturing cost.
Solution Approach 2:
The drive system performs self-diagnosis through the abnormality detection unit and self-adjustment by automatically redistributing drive responsibilities when one element becomes abnormal. This self-service capability eliminates the need for external backup systems or manual intervention, reducing overall system cost while maintaining reliability.
3Reliability
If a failsafe circuit with abnormality detection is added, then reliability is improved, but device complexity increases
Solution Approach 1:
The abnormality detection unit serves as an intermediary between the drive elements and the control system. It monitors the operational status of drive elements and communicates abnormality information, enabling automatic adjustment of drive responsibilities without requiring complex control circuitry or manual intervention.
Solution Approach 2:
The system implements continuous feedback through the abnormality detection unit that monitors drive element status and automatically adjusts drive responsibilities based on detected conditions. This feedback mechanism ensures reliable operation while maintaining relatively simple circuit structure by using straightforward monitoring and automatic response.
Data Source
AI summary
A load drive apparatus includes: a first drive element that drives a first load; a second drive element that drives a second load; a control circuit that controls the first drive element and the second drive element; a power supply circuit that supplies electric power; and a failsafe circuit that includes an abnormality detection portion detecting whether an abnormality occurs in at least one of the control circuit and the power supply circuit, the failsafe circuit controlling the first drive element and the second drive element to drive the first load and the second load when the abnormality detection portion has detected that an abnormality occurs in at least one of the control circuit and the power supply circuit and also when the load drive apparatus receives at least one of a command directing a drive of the first load and a command directing a drive of the second load.