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Drive circuit with current balance for CCFL (Cold Cathode Fluorescent Lamp) tubes

A driving circuit, current balance technology, applied in the direction of instruments, static indicators, etc., can solve the problem that the current balance of CCFL lamps cannot be guaranteed, and achieve the effect of consistent lighting

Inactive Publication Date: 2011-09-14
SHENZHEN SKYWORTH RGB ELECTRONICS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The present invention proposes a drive circuit for CCFL lamps with current balance, which solves the technical problem that the current drive circuit for CCFL lamps cannot guarantee the current balance of each CCFL lamp

Method used

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  • Drive circuit with current balance for CCFL (Cold Cathode Fluorescent Lamp) tubes
  • Drive circuit with current balance for CCFL (Cold Cathode Fluorescent Lamp) tubes
  • Drive circuit with current balance for CCFL (Cold Cathode Fluorescent Lamp) tubes

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Embodiment Construction

[0014] The present invention provides a drive circuit for CCFL tubes in an LCD backlight module. The drive circuit includes a current balance circuit that equalizes the current flowing through each CCFL tube, so that the luminous brightness of each CCFL tube is equal , So as to ensure that the LCD backlight module has uniform and sufficient brightness.

[0015] Such as figure 2 As shown, the driving circuit of the CCFL lamp tube of the present invention includes: a DC-AC conversion circuit that converts an input DC voltage into an AC voltage for driving multiple CCFL tubes; a high-voltage transformer T1 and a primary side connected to the DC-AC conversion circuit High-voltage transformer T2, the secondary side of high-voltage transformer T1 generates high-voltage HV1, and the secondary side of high-voltage transformer T2 generates high-voltage HV2; the primary side is connected to the PWM drive control circuit, and the secondary side is connected to the isolation drive transform...

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Abstract

The invention provides a drive circuit with current balance for CCFL (Cold Cathode Fluorescent Lamp) tubes. The drive circuit comprises a direct current-alternating current conversion circuit, a PWM (Pulse-Width Modulation) drive control circuit, a first high voltage transformer, a second high voltage transformer and a plurality of CCFL tube branches which are connected in parallel, wherein each CCFL tube branch comprises a first triode and a second triode; the emitter of the first triode is mutually connected with the emitter of the second triode, and the base electrode of the first triode and the base electrode of the second triode are connected with a current feedback circuit; the anode of a first diode is connected with the emitter of the first triode, and the cathode of the first diode is connected with the collector of the first triode; the anode of a second diode is connected with the emitter of the second triode, the cathode of the second diode is connected with the collector of the second triode; and the first CCFL tube is connected in series between a first capacitor and the collector of the first triode, and the second CCFL tube is connected in series between a second capacitor and the collector of the second triode. By adopting the drive circuit, currents flowing through the CCFL tubes are equal, and the circuit has a simple structure.

Description

Technical field [0001] The present invention relates to a driving circuit of an LCD backlight module, in particular to a current balance circuit in a cold cathode fluorescent lamp (CCFL) driving circuit. Background technique [0002] Cold cathode fluorescent lamps (CCFL, Cold Cathode Fluorescent Lamp) are widely used in LCD backlight modules for backlight displays. Generally, the lighting and operation of the CCFL tube require a relatively high AC voltage, which is provided by the driving circuit. [0003] Since the LCD backlight module needs to use multiple CCFL tubes, and the brightness of each tube needs to be the same directly, that is, the current of the CCFL tube needs to be consistent. If the drive circuit only applies high voltage to the two poles of the CCFL lamp, since the characteristics of each CCFL lamp are inconsistent, whether it is starting or working normally, it is necessary to add an additional CCFL lamp current balance circuit to force the current of each CCFL ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G09G3/34G09G3/36
Inventor 王俊永
Owner SHENZHEN SKYWORTH RGB ELECTRONICS CO LTD
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