Crest factor overcurrent protection circuit applied to electronic ballast

Abstract

The invention discloses a crest factor overcurrent protection circuit applied to an electronic ballast, and mainly aims to solve the problem that the service life of the electronic ballast is shortened due to no overcurrent protection of a resonant inductor in a resonant network of the conventional electronic ballast. The crest factor overcurrent protection circuit comprises a current sampling circuit, an averaging circuit and a comparison circuit, wherein the averaging circuit is connected between the current sampling circuit and the comparison circuit and is used for averaging transient voltage signals output by the current sampling circuit, multiplying the mean value to obtain an average voltage signal representing an inductive current mean value, and outputting the average voltage signal to the other input end of the comparison circuit; and the comparison circuit compares the average voltage signal with the transient voltage signal output by the current sampling circuit and outputting a crest factor overcurrent protection signal to realize the crest factor overcurrent protection of different inductors. The crest factor overcurrent protection circuit can be used for overcurrentprotection of the electronic ballast and failure detection of a fluorescent lamp.

Description

technical field [0001] The invention belongs to electronic circuits, in particular to a protection circuit, which can be applied to crest factor overcurrent protection in electronic ballasts. Background technique [0002] With the advantages of high operating frequency, low power consumption, high efficiency, and small size, electronic ballasts have gradually replaced traditional magnetic ballasts and penetrated into various lighting systems. The resonant network of electronic ballasts is composed of resonant inductors, resonant capacitors and lamps. In applications, electronic ballast chips are generally packaged together with resonant inductors and resonant capacitors, and then connected to corresponding fluorescent lamps, so even if the chip itself is not damaged, If the resonant inductor is damaged, it is considered that the electronic ballast is damaged. [0003] When the fluorescent lamp has been ignited and working normally, if the lamp is broken or the lamp is remov...

AI Technical Summary

Problems solved by technology

But for the same electronic ballast, the type of fluorescent lamp is different, the corresponding resonant network parameters are different, and the maximum current that different resonant inductors can bear is different, so it is impossible to realize overcurrent protection for resonant inductors

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