Asymmetric Driving Waveform Electronic Ballast for Fluorescent Lamp Striation
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Solution Overview
Problem
Conventional electronic ballasts for fluorescent lamps suffer from striation phenomena at low temperatures or low power, leading to flickering and limited dimming range, and existing solutions either reduce lamp lifetime or increase switching losses.
Innovation Solution
An electronic ballast that generates an asymmetric driving waveform with different current amplitudes and time spans for discharging and turning off two switch units, using a high-frequency push-pull inverter and a driving controller module with specific resistor and diode configurations to mismatch discharge times, while maintaining similar charge waveform portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a DC component is added into the driving signal to solve striation phenomena, then the striation phenomenon is eliminated, but the lifetime of the fluorescent lamp is reduced due to continuous consumption of one side of the filament material
Solution Approach 1:
The patent applies asymmetry by creating an asymmetric driving waveform where the discharge waveform portions of the two switch units are different in current amplitudes and time spans, while the charge waveform portions remain substantially the same. This asymmetric design eliminates striation phenomena without requiring a DC component, thereby avoiding the harmful effect of continuous filament consumption and extending lamp lifetime.
2Object-affected harmful factors
If an asymmetric waveform is provided as the driving signal to solve striation phenomena, then the striation phenomenon is eliminated, but one of the power switch units is driven into over saturation state increasing switching loss and operating temperature
Solution Approach 1:
The patent applies local quality by making only the discharge waveform portions asymmetric while keeping the charge waveform portions substantially the same for both switch units. This localized asymmetry in the discharge phase allows elimination of striation phenomena without causing over saturation of the power switch units, thereby avoiding increased switching losses and operating temperatures.
3Loss of energy
If conventional symmetric driving signal is used, then the power switch units operate efficiently, but striation phenomena occur at low temperature or low power reducing visual experience and dimming range
Solution Approach 1:
The patent applies dynamics by making the discharge waveform portions adaptive and different for the two switch units, allowing the system to dynamically adjust the discharge characteristics to eliminate striation phenomena at low temperature or low power conditions, while maintaining efficient operation of the power switch units through controlled asymmetric discharge.
Data Source
AI summary
An electronic ballast for a light emitting load is provided, and includes a transformer module, a resonance module, a high-frequency push-pull inverter and a driving controller module. The high-frequency push-pull inverter includes a first switch component and a second switch component. The driving controller module is used for generating and providing an asymmetric driving waveform to the first switch component and the second switch component. The asymmetric driving waveform includes a first discharging waveform portion for discharging and turning off the first switch component, and also a second discharging waveform portion for discharging and turning off the second switch component. The first and second discharging waveform portions are different in current amplitudes and time spans.