Filament control device for hot-cathode electric ballast

Abstract

The present invention relates to a hot cathode electronic ballast filament control device, which comprises a lamp tube, a half-bridge drive circuit and an electronic ballast control integrated circuit, wherein an inductor L and a resonant capacitor C2 are connected in series between the half-bridge drive circuit and the lamp tube, and both ends of the resonant capacitor C2 are connected at one end of the filament of both ends of the lamp tube in parallel; the other end of the filament of both ends of the lamp tube is connected with a preheating capacitor C1 in parallel; a resonant switch for controlling the resonant capacitor C2 is connected between the resonant capacitor C2 and the filament of the lamp tube in series, a preheating switch for controlling the preheating capacitor C1 is connected between the preheating capacitor C1 and the filament of the lamp tube in series, a switching control circuit is arranged among the electronic ballast control integrated circuit, the resonant switch and the preheating switch, the electronic ballast control integrated circuit controls the lamp tube to be accessed to the preheating capacitor in the preheating process of the filament through the switching control circuit and simultaneously the resonant capacitor is turned off, during the operating process of the filament, the preheating capacitor is turned off and the resonant capacitor is accessed simultaneously, the switching and access of the preheating switch and the resonant switch is controlled according to the preheating time set, the lamp tube can work normally, and the filamentis opened at the same time.

Description

technical field [0001] The invention belongs to an electronic ballast circuit, in particular to a filament control circuit of a fluorescent lamp hot cathode electronic ballast and a design method thereof. Background technique [0002] Fluorescent lamps need to be preheated and then start to emit light when they are triggered. However, in the prior art, after the fluorescent lamps are triggered, the filament is still in a conduction state, especially when T5 fluorescent lamps are powered by ordinary electronic ballasts since they came out, it is found that the filament current is greater than that of the lamp tube Current defects. Although a lot of improvements have been made, it can only achieve low current. Due to the geometric size and physical characteristics of T5 fluorescent lamps, it must be done in the power supply part of the electronic ballast to give full play to its characteristics of high light efficiency and long life. new improvements. Contents of the invent...

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Problems solved by technology

[0002] Fluorescent lamps need to be preheated and then start to emit light when they are triggered. However, in the prior art, after the fluorescent lamps are triggered, the filament is still in a conduction state, especially when T5 fluorescent lamps are powered by ordinary electronic ballasts since they came out, it is found that the filament current is greater than that of the lamp tube current defect

Although a lot of improvements have been made, it can only achieve low current. Due to the geometric size and physical characteristics of T5 fluorescent lamps, it must be done in the power supply part of the electronic ballast to give full play to its characteristics of high light efficiency and long life. new improvements

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