DC to DC Power Converter Failure Mode Detection
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Solution Overview
Problem
Existing LED driver circuits for automotive applications fail to effectively detect and handle both under-light and over-light failures, which are critical for ensuring driver safety and compliance with functional safety standards like ISO 26262.
Innovation Solution
A system comprising a lighting microcontroller communicatively coupled to a buck-type DC to DC power converter, which includes registers and controllers to detect failure modes such as timer failures, switch failures, sense transistor failures, and inductance changes, using average current control and communication protocols like SPI to monitor and adjust operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LED driver circuits are designed to detect failure modes, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple failure detection functions into a unified diagnostic system that monitors multiple parameters (inductor current, switch node voltage, duty cycle) through a single integrated controller. This merging approach enables comprehensive failure mode detection while reducing overall system complexity compared to implementing separate detection circuits for each failure type.
Solution Approach 2:
The diagnostic system is designed with multi-functionality to detect various failure modes (open circuit, short circuit, parameter drift) using the same hardware resources. The controller can selectively activate different diagnostic routines based on operational conditions, allowing a single device to perform multiple detection functions without proportionally increasing complexity.
2Reliability
If comprehensive failure detection is implemented, then safety is improved, but ease of operation deteriorates
Solution Approach 1:
The LED driver circuit performs self-diagnosis by automatically monitoring its own operational parameters and detecting anomalies. The controller continuously compares measured values against expected ranges and autonomously identifies failure modes without requiring external intervention or complex user procedures, thereby maintaining ease of operation while ensuring safety.
Solution Approach 2:
The system implements continuous feedback monitoring where the controller receives real-time data from sensors measuring inductor current, switch node voltage, and duty cycle. This feedback mechanism automatically adjusts operation or triggers failure detection algorithms, providing safety through continuous monitoring while keeping the system transparent and simple to operate.
Data Source
AI summary
Detecting failure modes of DC to DC power converters. In a system comprising a lighting microcontroller communicatively coupled to a direct current (DC) to DC power converter coupled to light-emitting diodes (LEDs) by way of an inductor, an example method may include: commanding, by the lighting microcontroller, the power converter to control an average current provided to the LEDs; reading, by the lighting microcontroller, values from the power converter; and detecting, by the lighting controller, one or more failure modes of the power converter based on the values.