CN203659400U - LED backlight drive circuit and liquid crystal TV set - Google Patents
LED backlight drive circuit and liquid crystal TV set Download PDFInfo
- Publication number
- CN203659400U CN203659400U CN201320846221.1U CN201320846221U CN203659400U CN 203659400 U CN203659400 U CN 203659400U CN 201320846221 U CN201320846221 U CN 201320846221U CN 203659400 U CN203659400 U CN 203659400U
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- Prior art keywords
- bjt
- field effect
- effect transistor
- resistance
- drive
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- Expired - Lifetime
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- 239000004973 liquid crystal related substance Substances 0.000 title claims abstract description 14
- 230000005669 field effect Effects 0.000 claims abstract description 25
- 239000004065 semiconductor Substances 0.000 description 12
- 238000005538 encapsulation Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 238000002955 isolation Methods 0.000 description 3
- 239000003990 capacitor Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
Images
Classifications
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/3406—Control of illumination source
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/30—Driver circuits
- H05B45/395—Linear regulators
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Circuit Arrangement For Electric Light Sources In General (AREA)
- Liquid Crystal Display Device Control (AREA)
- Led Devices (AREA)
Abstract
The utility model provides an LED backlight drive circuit and a liquid crystal TV set. The LED backlight drive circuit comprises a backlight source negative terminal, a drive IC, a bipolar junction transistor (BJT), a field effect transistor MOS and resistors; a control output end of the drive IC is connected with the source electrode of the field effect transistor MOS; the grid electrode of the field effect transistor MOS is connected with a switch-off reference voltage, and the drain electrode of the field effect transistor MOS is connected with the base electrode of the bipolar junction transistor (BJT); the emitting electrode of the BJT is connected with a feedback input end of the drive IC, and is grounded through the resistors; and the collecting electrode of the BJT is connected with the backlight source negative terminal. Through implementation of the LED backlight drive circuit and the liquid crystal TV set, the loss at a plate end can be reduced, and efficiency is improved.
Description
Technical field
The utility model relates to electronic technology field, relates in particular to a kind of LED-backlit driving circuit and liquid crystal TV set.
Background technology
In present LCD backlight drive, LED drive integrated circult (LED Driver integrated circuit) generally all needs to detect the voltage of Light Bar negative terminal, but backlight at PWM(Pulse Width Modulation, pulse broadband modulation) when light modulation or when 3D, the voltage of backlight Light Bar negative terminal is generally all larger, generally all at 30 ~ 50V, if output voltage is very high, the voltage of the negative terminal of Light Bar even may reach seventy or eighty volts so, but the withstand voltage of the detecting Pin of general LED Driver IC generally is 30V ~ 40V, so be all generally to increase an isolation camp effect transistor MOS at Light Bar negative terminal, make it in the time that Light Bar negative terminal voltage is large (being illustrated in figure 1 12V), close MOS, prevent from damaging IC.
There is following defect in prior art:
In prior art, the electric current of Light Bar all will flow through metal (metal)-oxide (oxid)-semiconductor (semiconductor) field effect transistor M OS, at this moment will select the MOS of a large encapsulation, prevent that MOS is overheated, also can lower efficiency, and loss on MOS increases simultaneously.
Utility model content
The utility model provides a kind of LED-backlit driving circuit and liquid crystal TV set, and described LED-backlit driving circuit comprises: backlight negative terminal, drive IC, bipolar junction transistor BJT, field effect transistor M OS, resistance; The control output end of described drive IC is connected with the source electrode of described field effect transistor M OS; The grid of described field effect transistor M OS connects shutoff reference voltage, and its drain electrode is connected with the base stage of described bipolar junction transistor BJT; The emitter of described BJT is connected with the feedback input end of described drive IC, and through described resistance eutral grounding; The collector of described BJT is connected with backlight negative terminal.
Wherein, described bipolar junction transistor BJT pipe is PNP transistor.
Wherein, described field effect transistor M OS is N-channel MOS pipe.
Wherein, described shutoff reference voltage is 12V.
Wherein, described resistance is the first resistance and the second resistance in parallel.
The utility model also provides a kind of liquid crystal TV set, comprising: backlight negative terminal, drive IC, bipolar junction transistor BJT, field effect transistor M OS, resistance; The control output end of described drive IC is connected with the source electrode of described field effect transistor M OS; The grid of described field effect transistor M OS connects shutoff reference voltage, and its drain electrode is connected with the base stage of described bipolar junction transistor BJT; The emitter of described BJT is connected with the feedback input end of described drive IC, and through described resistance eutral grounding; The collector of described BJT is connected with backlight negative terminal.
Wherein, described bipolar junction transistor BJT pipe is PNP transistor.
Wherein, described field effect transistor M OS is N-channel MOS pipe.
Wherein, described shutoff reference voltage is 12V.
Wherein, described resistance is the first resistance and the second resistance in parallel.
Implement the utility model, one isolation MOS is set between the B of the BJT utmost point and drive IC, when normal work, can not affect feedback voltage conducting to IC, and in light modulation process, backlight module BLU dwell period, the voltage of backlight negative terminal VLED-can be higher, at this moment saves conducting to metal-oxide-semiconductor by PN in bipolar junction transistor BJT pipe, metal-oxide-semiconductor is closed, can prevent that the high pressure of VLED-end from puncturing drive IC.Meanwhile, because MOS is arranged on the base stage (the B utmost point) of BJT, the electric current that flows through this utmost point is minimum, therefore can consider its loss on MOS, even if select the MOS of a less encapsulation, also can be reduced in the loss of plate end, raises the efficiency.
Accompanying drawing explanation
In order to be illustrated more clearly in the utility model embodiment or technical scheme of the prior art, to the accompanying drawing of required use in embodiment or description of the Prior Art be briefly described below, apparently, accompanying drawing in the following describes is only embodiment more of the present utility model, for those of ordinary skills, do not paying under the prerequisite of creative work, can also obtain according to these accompanying drawings other accompanying drawing.
Fig. 1 is the circuit diagram of the utility model LED-backlit driving circuit.
Embodiment
For solving the problems of the technologies described above, the utility model provides a kind of LED-backlit driving circuit, comprises backlight negative terminal, drive IC, bipolar junction transistor BJT, field effect transistor M OS, resistance; The control output end of described drive IC is connected with the source electrode of described field effect transistor M OS; The grid of described field effect transistor M OS connects shutoff reference voltage, and its drain electrode is connected with the base stage of described bipolar junction transistor BJT; The emitter of described BJT is connected with the feedback input end of described drive IC, and through described resistance eutral grounding; The collector of described BJT is connected with backlight negative terminal.
In specific implementation, described shutoff reference voltage is 12V, herein only for giving an example.In addition, the resistance being connected with the emitter of BJT is specially the first resistance R 1 and the second resistance R 2.Concrete, referring to Fig. 1, it is the physical circuit schematic diagram of the utility model LED-backlit driving circuit, describes the technical solution of the utility model in detail below in conjunction with Fig. 1 and specific embodiment.
LED-backlit driving circuit of the present utility model comprises: backlight negative terminal VLED-, drive IC, bipolar junction transistor BJT (Bipolar Junction Transistor), field effect transistor M OS(is called for short metal-oxide-semiconductor), the first capacitor C 1, the second capacitor C 2, the first resistance R 1, the second resistance R 2; The control output end of described drive IC is connected with the source electrode of described metal-oxide-semiconductor (the S utmost point); The grid (the G utmost point) of described metal-oxide-semiconductor connects shutoff reference voltage, is specially 12V power supply, and its drain electrode (D utmost point) is connected with the base stage (the B utmost point) of described BJT; The emitter (the E utmost point) of described BJT is connected with the feedback input end of described drive IC, and through the first resistance R 1 and second resistance R 2 ground connection of parallel connection; The collector (the C utmost point) of described BJT is connected with described backlight negative terminal VLED-.
In specific implementation, described bipolar junction transistor BJT pipe is PNP transistor, and described metal-oxide-semiconductor is N-channel MOS pipe.
The utility model is placed on isolation metal-oxide-semiconductor the B utmost point of BJT bipolar junction transistor, while normally work
Can not have influence on feedback voltage V 2 conductings to drive IC, but in light modulation process, backlight module BLU dwell period, the voltage of backlight negative terminal VLED-can be higher, at this time save conducting to metal-oxide-semiconductor by PN in PNP pipe, metal-oxide-semiconductor is closed, just can prevent that the high pressure of VLED-end from puncturing drive IC.Meanwhile, because metal-oxide-semiconductor is to use at the B of the BJT utmost point, the electric current that flows through this utmost point is minimum, so can consider its loss on MOS, can select the MOS of a less encapsulation, also can be reduced in the loss of plate end, raises the efficiency.
The utility model also provides a kind of liquid crystal TV set, and the structure of its LED-backlit driving circuit is identical with the structure of above-mentioned LED-backlit driving circuit, does not repeat them here.
It should be noted that; what the utility model was described is a kind of product form of LED-backlit driving circuit and liquid crystal TV set; other meets the product of structure described in the utility model; even if material, device name, outward appearance, device are put order etc., not affect the factor of product performance not identical, still belongs to the scope of the utility model protection.
Above content is in conjunction with concrete preferred implementation further detailed description of the utility model, can not assert that concrete enforcement of the present utility model is confined to these explanations.For the utility model person of an ordinary skill in the technical field, without departing from the concept of the premise utility, can also make some simple deduction or replace, all should be considered as belonging to protection domain of the present utility model.
Claims (10)
1. a LED-backlit driving circuit, is characterized in that, comprising: backlight negative terminal, drive IC, bipolar junction transistor BJT, field effect transistor M OS, resistance; The control output end of described drive IC is connected with the source electrode of described field effect transistor M OS; The grid of described field effect transistor M OS connects shutoff reference voltage, and its drain electrode is connected with the base stage of described bipolar junction transistor BJT; The emitter of described BJT is connected with the feedback input end of described drive IC, and through described resistance eutral grounding; The collector of described BJT is connected with backlight negative terminal.
2. LED-backlit driving circuit as claimed in claim 1, is characterized in that, described bipolar junction transistor BJT pipe is PNP transistor.
3. LED-backlit driving circuit as claimed in claim 2, is characterized in that, described field effect transistor M OS is N-channel MOS pipe.
4. LED-backlit driving circuit as claimed in claim 3, is characterized in that, described shutoff reference voltage is 12V.
5. LED-backlit driving circuit as claimed in claim 4, is characterized in that, described resistance is the first resistance and the second resistance in parallel.
6. a liquid crystal TV set, is characterized in that, comprising: backlight negative terminal, drive IC, bipolar junction transistor BJT, field effect transistor M OS, resistance; The control output end of described drive IC is connected with the source electrode of described field effect transistor M OS; The grid of described field effect transistor M OS connects shutoff reference voltage, and its drain electrode is connected with the base stage of described bipolar junction transistor BJT; The emitter of described BJT is connected with the feedback input end of described drive IC, and through described resistance eutral grounding; The collector of described BJT is connected with backlight negative terminal.
7. liquid crystal TV set as claimed in claim 6, is characterized in that, described bipolar junction transistor BJT pipe is PNP transistor.
8. liquid crystal TV set as claimed in claim 7, is characterized in that, described field effect transistor M OS is N-channel MOS pipe.
9. liquid crystal TV set as claimed in claim 8, is characterized in that, described shutoff reference voltage is 12V.
10. liquid crystal TV set as claimed in claim 9, is characterized in that, described resistance is the first resistance and the second resistance in parallel.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320846221.1U CN203659400U (en) | 2013-12-20 | 2013-12-20 | LED backlight drive circuit and liquid crystal TV set |
| PCT/CN2014/070523 WO2015089924A1 (en) | 2013-12-20 | 2014-01-13 | Led backlight driving circuit and liquid crystal television set |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320846221.1U CN203659400U (en) | 2013-12-20 | 2013-12-20 | LED backlight drive circuit and liquid crystal TV set |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203659400U true CN203659400U (en) | 2014-06-18 |
Family
ID=50925765
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201320846221.1U Expired - Lifetime CN203659400U (en) | 2013-12-20 | 2013-12-20 | LED backlight drive circuit and liquid crystal TV set |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN203659400U (en) |
| WO (1) | WO2015089924A1 (en) |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20090187925A1 (en) * | 2008-01-17 | 2009-07-23 | Delta Electronic Inc. | Driver that efficiently regulates current in a plurality of LED strings |
| TWI379618B (en) * | 2008-06-30 | 2012-12-11 | Green Solution Tech Co Ltd | Led driving circuit and mos module thereof |
| CN102708809A (en) * | 2012-06-21 | 2012-10-03 | 深圳市华星光电技术有限公司 | LED backlight drive circuit, liquid crystal display device and production method |
| CN202758591U (en) * | 2012-08-03 | 2013-02-27 | 深圳Tcl新技术有限公司 | Backlight LED driving output circuit and television set |
| CN103093728A (en) * | 2013-01-29 | 2013-05-08 | 深圳市华星光电技术有限公司 | Light-emitting diode (LED) backlight drive circuit and liquid crystal displayer (LCD) |
| CN103177698B (en) * | 2013-03-27 | 2016-02-03 | 深圳市华星光电技术有限公司 | A kind of LED backlight drive circuit and backlight module |
-
2013
- 2013-12-20 CN CN201320846221.1U patent/CN203659400U/en not_active Expired - Lifetime
-
2014
- 2014-01-13 WO PCT/CN2014/070523 patent/WO2015089924A1/en active Application Filing
Also Published As
| Publication number | Publication date |
|---|---|
| WO2015089924A1 (en) | 2015-06-25 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term |
Granted publication date: 20140618 |
|
| CX01 | Expiry of patent term |