Backlight electric power

A technology of power supply and circuit is applied in the field of backlight power supply to achieve the effects of reduced cost, simple structure and improved reliability

Inactive Publication Date: 2008-09-03
ZHENJIANG HANBANG TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The technical problem to be solved by the present invention is to provide a low-cost backlight power supply with a high brightness ratio, which can use general-purpose chips, and aim at the situation that the cold cathode lamp backlight power supply used in the existing large-screen liquid crystal display uses a high-cost ASIC.

Method used

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Embodiment Construction

[0013] As shown in Figure 1, the backlight power supply circuit of the present invention is composed of a balanced sampling circuit, a dual operational amplifier integrated circuit IC1, a drive circuit, a boost circuit (1, 2, ... n), a lamp tube (1, 2, ... n ) and a balanced accumulator circuit.

[0014] The dual operational amplifier integrated circuit IC1 includes operational amplifier A1 and operational amplifier A2, pulse width modulation circuit, oscillation circuit, transistor Q1 and transistor Q2, connected to the power supply voltage, dimming voltage, and the feedback voltage of each lamp through their respective sampling circuits. The positive and negative terminals of the dual operational amplifiers A1 and A2 connected to IC1; the output terminals of A1 and A2 are connected in parallel to the pulse width modulation circuit; the pulse width modulation circuit is basically excited by the oscillation circuit, and then output to the triode Q1 and Q2 respectively The base...

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Abstract

The invention relates to a backlight power system for large-screen liquid crystal display (LCD), specifically to a backlight power for igniting multi-path cold cathode lamp through a control circuit. The circuit of the invention comprises a dual operational amplifier integrated circuit of which the input part is connected to a symmetric sampling circuit, and the output part of which is connected with a plurality of lighting tubes orderly through a drive circuit and a booster circuit; the feedback voltage output part of each lighting tube is connected to a symmetric accumulating circuit of the power voltage, the output part of which is then connected to the symmetric sampling circuit. The invention can provide a backlight power with high luminance ratio, universal chip and low cost.

Description

technical field [0001] The invention relates to a backlight power supply system for large-screen liquid crystal display, in particular to a backlight power supply for igniting multi-channel cold cathode lamps through a control circuit. Background technique [0002] At present, the backlight power used by large-screen LCD screens in the market all adopts ASICs with high cost and complex circuits, and only a few companies can produce them. Among the main technical indicators of the current backlight power supply, the common problems are that the input voltage range is narrow, only 8-15V DC; the brightness ratio of the dimming function is small, that is, the brightest / darkest<3000:1. According to the latest relevant technical reports, the brightness ratio of some backlight power supplies can reach 5000:1; and its dimming circuit generally adopts a pulse width adjustment circuit, which requires a high cost, and the production of the TV set is relatively complicated. Content...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G09G3/34G09G3/36G09G3/20G02F1/13357H05B37/02G02F1/1335
Inventor 潘银汉王昌
Owner ZHENJIANG HANBANG TECH
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