Cold cathode fluorescent lamp driver

Abstract

A cold-cathod fluorescence lamp driving device includes a master lamp driving circuit, an at least primary lamp driving circuit, a master lamp, an at least primary lamp, at least two photo sensors, a master lamp feedback control circuit and an at least primary lamp feedback control circuit, among which, the said primary and each sub lamp is corresponding to one photosensor to detect its brightness, the photosensor corresponding to the master lamp outputs current to the said master and each sub lamp feedback control circuits and compares current with that output by the photosensor corresponding to each sub lamp, so as to regulate the driving current to reach the aim of equal brightness drive.

Description

【Technical field】 [0001] The invention relates to a driving device for a cold cathode fluorescent lamp, in particular to a driving device for supplying power to a plurality of cold cathode fluorescent lamps. 【Background technique】 [0002] The circuit structure of the CCFL driving device in the prior art can be roughly divided into three sub-architectures: one is the self-resonant boost circuit, which is responsible for lighting the CCFL; the other is the pulse width modulation control circuit and the pre-compensation circuit. The circuit is responsible for the adjustment of the driving current; the third is the feedback control circuit, which is responsible for the brightness stability and overvoltage protection of the cold cathode fluorescent lamp. [0003] In the prior art, the cold cathode fluorescent lamp driving device provides the high voltage required for driving the cold cathode fluorescent lamp through a self-resonant boost circuit, and uses a pulse width modulatio...

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Problems solved by technology

[0006] However, in the prior art, for the light source required by the backlight module, two or more cold-cathode fluorescent tubes are often used. , the practice in the prior art is to select a specific lamp as the main lamp, and control the current of each of the other lamps separately by means of feedback compensation through the detection of its driving current, so that it follows the selected main lamp. The current change of the lamp tubes can achieve the consistency of the driving current of all the lamp tubes. This method can achieve the purpose of approximately equal brightness driving, but due to the slight difference in the electro-optical characteristics of each lamp tube (generally under the same current driving condition The difference in luminance of the same type of lamps is within about 2%), so controlling the driving current of individual lamps to the same state can only approximately achieve the purpose of driving the lamps at equal brightness

And with the prolongation of the use time, the aging degree of the lamp tube is different, and its electro-optic characteristics will also change, thus exacerbating the phenomenon of uneven brightness of the lamp tube

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