Matrix Headlamp PWM Synchronization via Master Controller
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Solution Overview
Problem
Conventional matrix headlamp systems face challenges in synchronizing PWM frequency and phase across multiple LED controllers, leading to potential flickering or drastic brightness changes in the headlamp beam, which can disturb oncoming traffic and compromise road illumination.
Innovation Solution
A matrix headlamp control apparatus with a Master LED controller IC generating a PWM synchronization signal to synchronize frequency and phase across Slave LED controller ICs, utilizing a digital control block with frequency and phase synchronization units, and an oscillator to derive internal clock signals, ensuring synchronized PWM signals without flicker or drastic brightness changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple LED controller ICs are used to control different LED groups in a matrix headlamp, then the headlamp can provide effective beam control and blanking regions, but PWM synchronization issues cause flickering and drastic brightness changes
Solution Approach 1:
The patent introduces a Master LED controller IC as an intermediary that generates a PWM synchronization signal to coordinate all Slave LED controller ICs. This Master controller acts as a central mediator that ensures all LED groups are controlled with synchronized PWM signals, eliminating flickering and brightness instability while maintaining the ability to create blanking regions and control beam patterns across multiple LED groups.
Solution Approach 2:
The patent implements a feedback mechanism where the PWM synchronization signal generated by the Master LED controller IC is distributed to all Slave LED controller ICs. This creates a closed-loop synchronization system where the Master controller's output serves as the reference for all other controllers, ensuring that brightness changes are coordinated and stable across the entire LED matrix without flickering.
2Reliability
If PWM synchronization is implemented across multiple LED controllers, then flicker is reduced, but system complexity increases due to additional synchronization circuitry
Solution Approach 1:
The patent merges the synchronization function into the Master LED controller IC, which generates the PWM synchronization signal that all other controllers follow. Instead of each controller having independent synchronization circuitry, the system combines the synchronization role into a single Master controller, reducing overall system complexity while maintaining reliable brightness stability across all LED groups.
Solution Approach 2:
The Master LED controller IC performs multiple functions: it controls its own LED group and simultaneously generates the PWM synchronization signal for all other Slave LED controller ICs. This multi-functionality reduces the need for separate synchronization hardware, simplifying the overall system while ensuring coordinated brightness control across the entire matrix headlamp.
3Reliability
If precise PWM synchronization is achieved across all LED controllers, then no flicker occurs, but manufacturing cost increases due to additional synchronization components
Solution Approach 1:
The Master LED controller IC serves as a cost-effective intermediary that generates PWM synchronization signals using standard electronic components. Instead of requiring expensive precision synchronization hardware in each controller, the system uses a single Master controller with conventional oscillators and signal distribution circuitry, achieving flicker-free operation while keeping manufacturing costs reasonable.
Solution Approach 2:
The Master LED controller IC generates its own PWM synchronization signal using internal oscillators and circuitry, eliminating the need for external precision clock sources or complex synchronization hardware. This self-service approach reduces component costs and simplifies manufacturing while maintaining the reliability needed to prevent flickering and brightness instability.
Data Source
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AI summary
A matrix headlamp control apparatus (1) for controlling a brightness of a headlamp comprising a matrix of light-emitting diodes, LEDs, consisting of LED groups of light-emitting diodes, wherein each LED group is controlled by an associated LED controller integrated circuit, IC (2), wherein a Master LED controller IC is adapted to generate a PWM synchronization signal (PWMsync) applied to Slave LED controller ICs to synchronize frequency and phase of all pulse width modulated, PWM, signals supplied by the different LED controller ICs to the respective LED groups.