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Discharging fluorescent tube circuit capable of controlling starating time and possessing overvoltage protection

A technology for discharge lamps and electric light tubes, which is applied in the field of drive circuits, and can solve problems such as harming users and maintenance personnel, damaging backlight modules, and poor contact of CCFL

Inactive Publication Date: 2004-03-03
QISDA CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since the DC / AC conversion circuit driving the CCFL can output extremely high AC voltage, if the CCFL is not installed when the backlight module is started, or the CCFL is in poor contact during operation, or even the CCFL has failed, these situations will cause no overvoltage The traditional CCFL drive circuit with protection function continuously outputs excessive voltage, which may damage the backlight module or even hurt the user or maintenance personnel

Method used

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  • Discharging fluorescent tube circuit capable of controlling starating time and possessing overvoltage protection
  • Discharging fluorescent tube circuit capable of controlling starating time and possessing overvoltage protection
  • Discharging fluorescent tube circuit capable of controlling starating time and possessing overvoltage protection

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Embodiment Construction

[0023] According to the present invention, the discharge lamp circuit 100 with controllable ignition time and overvoltage protection such as figure 1 As shown, it includes a driving circuit 110 , a detection circuit 120 , a timing circuit 130 and a starting circuit 140 . The driving circuit 110 can generate the starting voltage of the cold cathode fluorescent lamp (CCFL) LP1 and provide the lamp current I flowing through the lamp LP1 LP , the resistor R1 and the diode D1 are connected in series with the lamp LP1, and the lamp current I LP Feedback to the driving circuit 110, so that the driving circuit 110 can adjust the brightness of the lamp LP1. The detection circuit 120 is connected to the lamp LP1 via the diode D1 to detect whether there is current passing through the lamp LP1 . The timing circuit 130 is connected and controlled by the detection circuit 120, and can adjust and determine a set period T ON , so during the light-off phase of the lamp LP1 during this set p...

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Abstract

The circuit includes a drive circuit, a detection circuit, a timing circuit and starting circuit. The drive circuit generates trigger voltage for discharge lamp tube, and provides lamp current passing through discharge lamp tube. The detection circuit can detect lamp tube current. The timing circuit controlled by the detection circuit forms a reference voltage at the end of setting period in ignition phase in order to control ignition time of discharge lamp tube. Moreover, before the reference voltage is formed, the starting circuit makes the drive circuit possible to apply trigger voltage on discharge lamp tube sostenuto within ignition time in order to trigger discharge lamp tube. If the detection circuit detects no lamp current, the starting circuit turns the drive circuit off in order to prevent over voltage.

Description

technical field [0001] The invention relates to the field of driving circuits for discharge lamps, in particular to circuits suitable for backlight modules of liquid crystal display (Liquid Crystal Display, LCD) devices. Background technique [0002] In recent years, more and more information, communication, and consumer electronics products use LCD screens to display information. Generally speaking, LCD panels use a backlight module that includes a discharge lamp to provide light for the images displayed on the panel. At present, cold-cathode fluorescent lamps (Cold-Cathode Fluorescent Lamp, CCFL) among various types of discharge lamps can best meet the needs of LCD backlight modules, while backlight modules must have high-efficiency DC / AC conversion circuits to supply high AC voltage to the CCFL for normal operation. [0003] The kick-off or strike voltage required to ignite a CCFL is 2-3 times the AC voltage required for its normal operation, which can reach thousands of...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H05B41/282H05B41/285
Inventor 叶佳翅许永沂
Owner QISDA CORP