LED Driver Series Module Prevents Current Overshoot
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Solution Overview
Problem
Existing LED drivers face challenges in preventing current overshoot and undershoot when adjusting the number of active LEDs, particularly in automotive applications, which can lead to LED failure, and often require complex microcontrollers or software to manage power output.
Innovation Solution
A system comprising a load module, power module, series module, and control module that selectively bypasses LEDs and adjusts power dissipation to limit current output, using a series module to prevent overshoot without relying on microcontrollers, by modifying resistance to control power delivery based on target power thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the number of active LEDs is reduced from high beam to low beam setting, then the power consumption is reduced, but current overshoot occurs at the LED string
Solution Approach 1:
The series module proactively limits the power output before current overshoot can occur when LEDs are switched out. By preemptively controlling the power delivery through resistance modification, the system prevents the harmful current spike before it affects LED reliability.
Solution Approach 2:
The series module acts as an intermediary component between the power module and the LED string. It mediates the power transfer by dissipating a portion of the supply power and outputting a controlled remaining portion, thereby preventing current overshoot while enabling safe LED configuration changes.
2Reliability
If a microcontroller is used to control power output to prevent current overshoot, then current stability is improved, but device complexity increases
Solution Approach 1:
The series module autonomously limits power output based on the detected LED configuration without requiring external microcontroller intervention. The module self-regulates the power delivery by modifying its resistance, eliminating the need for complex control software or microcontrollers while maintaining current stability.
Solution Approach 2:
The patent extracts the power limiting function from the control module/microcontroller and places it directly in the series module. This separation removes the need for complex digital control logic, simplifying the overall system while maintaining the ability to prevent current overshoot.
3Reliability
If the series module dissipates more power to limit current output, then current stability is improved, but energy efficiency decreases
Solution Approach 1:
The series module dissipates only the minimum necessary portion of power required to prevent current overshoot, rather than excessively limiting all power output. By carefully controlling the resistance modification, it achieves just enough power limiting to ensure current stability while maximizing energy delivery to the LEDs.
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
Effectively prevents current overshoot and undershoot in LED strings during beam setting changes, simplifying the system by eliminating the need for microcontrollers and reducing complexity, while ensuring stable power delivery to LEDs.
Implementation Method 1
The series module is configured to receive the supply power from the power module, dissipate a portion of the supply power, and output, to the subset of LEDs, a remaining portion of the supply power as a load power
Data Source
AI summary
In one example, a system includes a load module, a power module, a series module, and a control module. The power module is configured to generate a supply power. The load module is configured to select a subset of light emitting diodes (LEDs) from a set of LEDs. The series module is configured to receive the supply power from the power module, dissipate a portion of the supply power, and output, to the subset of LEDs, a remaining portion of the supply power as a load power. The control module is configured to drive the series module to limit an amount of power at the subset of LEDs.