Automotive LED Driver Mixer to Prevent Microcontroller Resets
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Solution Overview
Problem
LED drivers in automotive lighting systems reset when both Daytime Running Light (DRL) and Turning Indicator (TI) functions are disabled, losing memory of ongoing processes and requiring additional power lines or systems to maintain microcontroller functionality.
Innovation Solution
An electronic device with a mixer that combines a non-permanent signal and a permanent signal, ensuring the microcontroller receives a voltage higher than the supply threshold, preventing resets by using a mixer with inputs and voltage stabilizers to maintain functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate power line is used to keep the microcontroller alive, then the driver can maintain functionality without resetting, but an extra input is needed which increases device complexity
Solution Approach 1:
The patent combines multiple signal inputs (DRL signal and TI signal) into a single power and signal input line through a mixer circuit. This merging allows the driver to receive both power and control signals through one interface, eliminating the need for a separate power line while maintaining microcontroller functionality.
Solution Approach 2:
The power and signal input line serves dual purposes: it provides power to the driver and simultaneously carries control signals for both DRL and TI functions. This multi-functionality eliminates the need for dedicated separate lines, reducing device complexity while ensuring continuous operation.
2Device complexity
If the driver uses a single power and signal input, then device complexity is reduced, but the microcontroller resets when voltage falls below the threshold
Solution Approach 1:
The mixer acts as an intermediary circuit that processes the non-permanent DRL and TI signals, combining them with a permanent reference signal to generate a stable output that maintains the microcontroller voltage above the reset threshold throughout all operational cycles.
Solution Approach 2:
The mixer circuit preliminarily processes the control signals before they reach the driver, ensuring that the voltage level is always sufficient to prevent microcontroller reset. This preliminary action occurs continuously, preparing the signal in advance before the driver needs to process it.
3Loss of energy
If the system resets during off cycles, then power consumption is reduced, but memory of ongoing processes is lost requiring auxiliary systems
Solution Approach 1:
The mixer continuously processes the control signals and maintains a continuous voltage output above the threshold level, even during periods when both DRL and TI are inactive. This continuity prevents microcontroller reset and preserves memory of ongoing processes like derating, eliminating the need for auxiliary memory systems.
Data Source
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AI summary
The invention presents an electronic device (1) for an automotive lighting device, comprising a driver (2) and a mixer (3). The driver (2) comprises a power and signal input (21) and has a supply voltage threshold, in such a way that the microcontroller is configured to reset if the voltage value in the power and signal input (21) is lower than the supply voltage threshold. The mixer (3) comprises an output (34) connected to the power and signal input (21) of the driver (2), and is configured to provide an output signal which is related to the highest between the non-permanent signal and the permanent signal inputs.