LED String Driver Control Using Forward-Voltage Switching
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Solution Overview
Problem
Existing LED driving systems for vehicle lamps are bulky and prone to heat dissipation due to numerous electronic components, and they lack efficient independent control of LED strings for different lighting and signaling functions.
Innovation Solution
A method and system that utilize a DC/DC converter with a microcontroller to toggle between current and voltage control modes, enabling selective activation and control of LED strings with varying forward voltages, allowing one string to act as a backup without additional control means, and optimizing the number of electronic components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If each LED string is controlled by its own driver circuit to regulate current, then independent control of each string is achieved, but the pin-count increases and the system becomes bulky with high heat dissipation
Solution Approach 1:
The patent merges the control functions for multiple LED strings into a single driver circuit. The driver circuit can selectively activate different strings by controlling the voltage output - when voltage is below the forward voltage of high-voltage strings, only low-voltage strings are activated. This consolidation reduces the number of electronic components and pin-count while maintaining independent control capability through voltage-level discrimination.
Solution Approach 2:
The invention utilizes forward voltage as a distinguishing parameter to enable selective activation of LED strings. By varying the output voltage of the single driver circuit below the forward voltage threshold of specific strings, the system can selectively activate only the desired strings (either low-voltage or high-voltage strings) without requiring separate driver circuits for each string.
2Reliability
If a secondary LED string is always activated to act as a voltage regulator for the main string, then voltage regulation is achieved, but the system cannot activate the main string alone and heat dissipation increases
Solution Approach 1:
The patent implements dynamic activation of LED strings based on operational requirements. The single driver circuit dynamically adjusts its output voltage to selectively activate either low-voltage strings, high-voltage strings, or both simultaneously. This dynamic control eliminates the need for a constantly active secondary string, allowing the main string to be activated alone when needed, thereby reducing unnecessary heat dissipation while maintaining voltage regulation capability through voltage-level management.
3Ease of operation
If additional control means are added to enable selective activation of specific LED strings, then independent control is improved, but production cost and heat dissipation increase
Solution Approach 1:
The single driver circuit is designed with multi-functionality to perform selective activation of different LED string configurations. It can activate low-voltage strings alone, high-voltage strings alone, or both simultaneously by simply adjusting the output voltage level. This universal control capability eliminates the need for additional control components or separate driver circuits, thereby reducing production cost while maintaining full selective activation functionality.
Data Source
Figure 1a~1b
Figure 1c~2
Figure 3~4a
AI summary
A method for enabling a light source comprising a set of at least two parallel strings (21) 22) of light-emitting diodes, each string having a forward voltage, wherein a first string (21), has a forward voltage higher than the forward voltage of the other strings (22). A method for manufacturing a driving system and a driving system. A light source comprising the driving system and a vehicle lamp.