Automotive LED Bias Circuit With Step-Up Dropout Compensation
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Solution Overview
Problem
Existing automotive lighting devices face challenges in ensuring correct LED biasing at low battery voltages due to high dropout voltage in traditional linear voltage regulators, limiting the minimum voltage threshold for proper operation.
Innovation Solution
Incorporating a step-up unit that increases the voltage level at an auxiliary input to compensate for the voltage dropout in the voltage regulator, allowing for a lower net voltage dropout and enabling correct LED biasing at lower battery voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a linear voltage regulator is used to ensure constant voltage in LEDs and driver, then voltage stability is improved, but dropout voltage increases
Solution Approach 1:
The voltage regulation system is segmented into two independent parts: a first voltage regulator for regulating battery voltage to a first regulated voltage, and a second voltage regulator for regulating the regulated voltage to a second regulated voltage. This segmentation allows each regulator to operate with optimized dropout characteristics, reducing the total voltage loss compared to a single regulator stage.
Solution Approach 2:
A capacitor is introduced as an intermediary energy storage element between the two voltage regulators. This capacitor stores energy during periods when the battery voltage is sufficient and releases it during voltage sags, effectively decoupling the dropout voltages of the two regulators and allowing the system to maintain regulation at lower input voltages than either regulator would require alone.
2Adaptability or versatility
If dropout voltage is reduced to allow lower battery voltage operation, then adaptability to low voltage conditions is improved, but voltage regulation capability may be compromised
Solution Approach 1:
The voltage regulation system is segmented into two independent parts: a first voltage regulator for regulating battery voltage to a first regulated voltage, and a second voltage regulator for regulating the regulated voltage to a second regulated voltage. This segmentation allows each regulator to operate with optimized dropout characteristics, reducing the total voltage loss compared to a single regulator stage.
Solution Approach 2:
A capacitor is introduced as an intermediary energy storage element between the two voltage regulators. This capacitor stores energy during periods when the battery voltage is sufficient and releases it during voltage sags, effectively decoupling the dropout voltages of the two regulators and allowing the system to maintain regulation at lower input voltages than either regulator would require alone.
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 effectively reduces the minimum battery voltage required for correct LED operation, optimizing LED performance across a wider range of voltage parameters and enhancing the reliability of automotive lighting systems.
Implementation Method 1
a step-up unit (3) comprising a step-up input (31) configured to be electrically fed between the power source (5) and the ground connection (6), this step-up unit (3) further comprising a step-up output (32) configured to provide a higher voltage than the voltage in the step-up input (31)
Data Source
Figure 1
Figure 2
Figure 3a
AI summary
The invention presents an automotive lighting device (10) comprising a voltage regulator (1) with a regulator input (11) and a regulated voltage output (13), a controlled light group with a light driver (4) and a plurality of light sources (2) and a step-up unit (3) with a step-up input (31) and a step-up output (32) configured to provide a higher voltage than the voltage in the step-up input (31). The controlled light group is configured to be fed by the regulated voltage output (13) and the voltage regulator (1) has an auxiliary input (12) being electrically connected to the step-up output (32).