LED Driver Jitter Correction via Timing Control
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Solution Overview
Problem
Conventional phase cut dimmers introduce visible luminance flicker in LED lamps due to jitter caused by mains noise, which is not filtered effectively by LED lamps with fast response behavior, leading to unsuitable solutions that require bulky and expensive filters or capacitors.
Innovation Solution
A controller that enables and disables the lamp driver at specific times independent of the dimmer's ignition time, using sensing and calculating means to adapt the driver's operation and eliminate jitter, thereby reducing or preventing luminance flicker without the need for bulky filters or capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional phase cut dimmers are used to control LED lamps, then power loss is reduced and construction is simplified, but visible luminance flicker occurs due to jitter from mains noise
Solution Approach 1:
The controller measures the actual ignition time of the dimmer before the mains voltage zero crossing and uses this information to pre-calculate and adjust the shutdown time of the LED driver. This preliminary measurement and adjustment prevents the luminance flicker caused by jitter without requiring additional filtering components.
2Object-affected harmful factors
If filters or capacitors are added to reduce luminance flicker, then visible flicker is reduced, but device complexity and cost increase
Solution Approach 1:
The patent replaces the mechanical/electrical filtering approach (using physical filters or capacitors) with a control-based solution. The controller uses timing measurements and calculations to compensate for jitter, substituting the need for bulky passive filtering components with an intelligent control algorithm.
3Object-affected harmful factors
If filters or capacitors are added to reduce luminance flicker, then visible flicker is reduced, but device size and cost increase
Solution Approach 1:
The patent extracts and eliminates the need for bulky filtering components (filters or capacitors) from the system. By using a control-based jitter compensation method, the solution removes the heavy passive components while maintaining the ability to reduce luminance flicker.
4Use of energy by moving object
If the lamp driver operates throughout the entire active period of the dimmer, then power efficiency is maximized, but luminance flicker occurs due to timing jitter
Solution Approach 1:
The controller implements a feedback mechanism by measuring the actual ignition time of the dimmer and using this information to adjust the shutdown time of the LED driver. This feedback loop ensures that the driver operates for the optimal duration to eliminate flicker while maintaining power efficiency.
Data Source
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AI summary
A controller and a method for controlling lamp drivers such as e.g. LED drivers for lamps having a fast response behavior such as e.g. LED lamps are proposed. They enable to substantially reduce or prevent a visible luminance flicker at such lamps when dimming the lamps with a conventional dimmer such as e.g. a phase cut dimmer. This can be achieved by switching off the lamp driver prematurely in such a way that a time jitter of a dimmer switching does not influence an on-time of the lamp driver. No bulky or expensive filters or capacitors are needed. Thus, a space-saving and/or inexpensive construction is enabled.