Light Source Supply Circuit Flicker Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power supply systems for light sources, such as switched mode power supplies, suffer from significant output voltage ripple, leading to visible flicker and the use of electrolytic capacitors with short lifetimes, especially at higher temperatures.
Innovation Solution
A supply circuit that adjusts the frequency components of the harmonic content of the power spectrum by controlling switches and controllers, reducing visible flicker without relying on electrolytic capacitors, by adjusting the voltage and current signals to minimize the 100 Hz frequency component, which is a major contributor to flicker.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a large electrolytic capacitor is used to reduce output voltage ripple, then visible flicker is reduced, but the lifetime of the capacitor decreases especially at higher temperatures
Solution Approach 1:
The patent changes the operating parameters of the power supply circuit by controlling the switching frequency and duty cycle to shape the output voltage waveform. By optimizing these parameters, the circuit reduces the ripple voltage amplitude without requiring large electrolytic capacitors, thereby extending capacitor lifetime while maintaining low visible flicker.
2Object-affected harmful factors
If a large electrolytic capacitor is used to reduce output voltage ripple, then visible flicker is reduced, but the device size increases
Solution Approach 1:
The patent optimizes the switching frequency and duty cycle parameters to minimize output voltage ripple. By changing these operational parameters, the circuit achieves low visible flicker without requiring large electrolytic capacitors, thereby reducing the overall device volume while maintaining effective flicker suppression.
3Object-affected harmful factors
If the switching frequency is increased to reduce ripple, then output voltage stability improves, but switching losses increase
Solution Approach 1:
The patent optimizes the switching frequency parameter to balance ripple reduction and switching losses. By carefully selecting and adjusting the switching frequency, the circuit achieves sufficient output voltage stability while minimizing energy losses, creating an optimal operating point that satisfies both requirements.
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
Supply circuits for supplying voltage and current signals to light sources (6) comprise switches (22, 32, 42, 52) and controllers (21, 31, 41, 51) to control the switches (22, 32, 42, 52) for reducing values of frequency components of harmonic content of power spectra of the light sources (6). By switching one of the voltage and current signals or by switching signals that result in one of the voltage and current signals, the other one of the voltage and current signals can be adjusted. The power spectrum of the light source (6) may be a function of the voltage and current signals. By adjusting one of them, the power spectrum can be adjusted such that values of frequency components of the harmonic content of the power spectrum are reduced. As a result, visible flicker is reduced in the light originating from the light source (6) without the use of energy storage capacitors for reducing this visible flicker.