Resonance capacitor adjusting element and current preheating type electronic ballast applicable to same

Abstract

The invention discloses a resonance capacitor adjusting element and a current preheating type electronic ballast applicable to the same, which are used for driving a lamp tube with a filament. The current preheating type electronic ballast comprises an alternating current-direct current conversion circuit, a control unit, an auxiliary voltage generation circuit and an inversion circuit, wherein the alternating current-direct current conversion circuit is used for converting an alternating current input voltage into a high-voltage direct current voltage; the inversion circuit is used for converting the high-voltage direct current voltage into an alternating current output voltage, outputting a resonance current and a filament current to the lamp tube, and comprises a resonance circuit and a resonance capacitor adjusting circuit; the resonance circuit provides energy for preheating the lamp tube; and the resonance capacitor adjusting circuit is connected with the resonance circuit and a detection element, and judges whether the inversion circuit starts operating through the detection element, and two high-voltage switching ends of the resonance capacitor adjusting circuit are correspondingly conducted or opened at a delay time after the inversion circuit starts operating, so as to change an equivalent capacitance value of the resonance circuit.

Description

technical field [0001] The invention relates to an electronic ballast, and in particular to a resonant capacitance adjustment element and a current preheating electronic ballast which is applicable to it, which can control the cross-voltage at both ends of the filament of the driven lamp tube. Background technique [0002] Lighting is the basic need of human beings. In recent years, with the frequent global economic, trade and commercial activities, and the improvement of the quality of home life, lighting power consumption has also risen. The overall lighting power demand is very considerable. Currently, the most widely used lamp body is A low-pressure gas discharge lamp is also called a fluorescent lamp or a fluorescent lamp. Therefore, if the energy saving of this low-pressure gas discharge lamp can be devoted to, considerable electric energy can be saved. In addition, with the evolution of the times and the improvement of social living standards, ordinary lighting drive ...

AI Technical Summary

Problems solved by technology

However, when the current preheating ballast is used for high-efficiency fluorescent lamps with high filament impedance (such as 8-15 ohms), since the filament is high impedance, the cross-voltage (such as 16V) at both ends of the filament will be higher than the threshold voltage at this time. In this way, it will cause unnecessary waste of energy and reduce the life of fluorescent lamps, and even cause high-efficiency fluorescent lamps to burn out

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