Light-adjustable electronic ballast

Abstract

The electronic ballast of illuminance adjusting type of this invention comprises a power factor correcting unit, a half-bridge inverse-converter, a resonance circuit, a illuminance adjusting signal circuit, a driving circuit and an igniting circuit, wherein said resonance circuit includes a first capacitor C1, a first inductor L1, second capacitor C2, a transformer T1, a gaseous discharge lamp with high power and a current transformer T2. One end of the first capacitor C1 is connected to the connecting points of two switching transistors S1 and S2 of the half-bridge inverse-converter, the other end is connected to one end of the inductor L1; the primary side of the transformer T1 is connected to the gaseous discharge lamp with high power and the primary side of the current transformer T2 is series first.

Description

technical field [0001] The present invention relates to electronic ballasts, especially dimming electronic ballasts for high intensity gas discharge lamps. Background technique [0002] Compared with inductive ballasts, electronic ballasts can be easily dimmed. The existing dimming electronic ballast includes a power factor corrector, a half-bridge inverter, a series resonant circuit composed of an inductor, a capacitor and a lamp connected in series or in parallel, a dimming signal circuit, a driving circuit and an ignition circuit. When working, the mains power enters the resonant circuit and the ignition circuit through the power factor corrector and the half-bridge inverter to provide alternating current and start high voltage to the lamp, and the dimming signal output by the dimming signal circuit controls the switch of the inverter through the driving circuit The tube is turned off or turned on. When this electronic ballast is used for frequ...

AI Technical Summary

Problems solved by technology

When this electronic ballast is used for frequency modulation and dimming, it adjusts the lamp power by changing the frequency and changing the impedance value of the inductance of the series resonant circuit. In order to obtain the required dimming range, a wide frequency modulation range (up to several times) is required. , when entering deep dimming, the circuit frequency is very high, and the circuit efficiency decreases. At the same time, as the frequency increases, the lamp current crest factor increases, which will affect the life of the lamp. Such a wide frequency range also poses challenges to the design of magnetic components.

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