Anti-arc electronic ballast of series resonance instant start type

Abstract

The invention discloses an anti-arc electronic ballast of a series resonance instant start type, comprising a half-bridge inverter start circuit. A node serially connected with two switching tubes (Q1 and Q2) of the half-bridge inverter is connected with a feedback pulse transformer (T) a primary winding (L0) of which is connected in series with an inductor (L3) to form a series resonance capacitor, the inductor (L3) is connected with a lighting tube and a series resonance capacitor (C4), and the secondary side of the feedback pulse transformer is provided with two windings (L4 and L5) which are respectively connected in series with a base loop of the switching tubes (Q1 and Q2). Under the abnormal conditions that the lighting tube is not activated or light feet are in poor contact, and the like, no matter the ballast is open-circuited or short-circuited, switching tube elements can not be damaged in case of lacking special protection circuits, nor is an arc with enough energy generated at the output end of the ballast because of the poor contact of the light feet so that various instant-start lighting tubes with the requirement for a high start voltage can be reliably and normally started. The invention has the advantages of simple circuit, high efficiency and low cost.

Description

technical field [0001] The invention relates to an electronic ballast for a gas discharge lamp for lighting, in particular to a series resonance instant start type anti-arc electronic ballast. Background technique [0002] The electronic ballast provides high-frequency voltage and current to the lamp load to ignite and maintain the normal operation of the lamp. Due to the characteristics of the gas discharge lamp, before the lamp is activated and ignited, there must be a high activation voltage to ignite the lamp. Therefore, there must be a high voltage on the output terminal of the ballast before the lamp tube is not started. Once the ballast is unloaded during use, the lamp tube is disconnected, the output terminal of the ballast is short-circuited, and the lamp tube In case of abnormal conditions such as non-activation or poor contact of the lamp pins, the ballast may be damaged due to the overload of the switching element; the high voltage output by the ballast may ...

AI Technical Summary

Problems solved by technology

However, most series resonant instant-start electronic ballasts use isolation transformer output. When the lamp tube is removed or a certain lamp pin is poorly connected in this instant-start circuit, the resonant tank circuit is in an empty state, which will cause the resonant current The sharp increase, the rise of the resonant voltage on the resonant capacitor will cause a larger arc at the lamp pin, and the increased resonant current will also cause serious consequences for the switching elements in the inverter to be burned

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