CN202068494U - Control circuit used for eliminating screen flash occurring in AC shutdown of liquid crystal display television - Google Patents
Control circuit used for eliminating screen flash occurring in AC shutdown of liquid crystal display television Download PDFInfo
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- CN202068494U CN202068494U CN2011200964808U CN201120096480U CN202068494U CN 202068494 U CN202068494 U CN 202068494U CN 2011200964808 U CN2011200964808 U CN 2011200964808U CN 201120096480 U CN201120096480 U CN 201120096480U CN 202068494 U CN202068494 U CN 202068494U
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- liquid crystal
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- power supply
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Abstract
A control circuit used for eliminating a screen flash occurring in AC shutdown of a liquid crystal display television comprises a PNP triode, a NPN triode, three diodes, two capacitors and a plurality of resistors. The control circuit is provided with a switch signal input interface and a power supply plug interface. When the control circuit is in use, the switch signal input interface is connected with a switch signal pin in a backlight circuit interface end of the present liquid crystal display, and the power supply plug interface is connected with a power supply pin in the backlight circuit interface end of the present liquid crystal display. The control circuit can effectively solve the problem that the screen flash occurs in AC shutdown of the liquid crystal display television, and service life of the liquid crystal display is reduced.
Description
Technical field:
The utility model relates to field of television, relates in particular to the control circuit that is used to eliminate liquid crystal TV set screen flicker when ac dump.
Background technology:
Liquid crystal TV set is implemented shutdown to be had usually by remote controller and the direct two kinds of operator schemes of mains switch of closing, the pattern of directly closing mains switch claims ac dump, when ac dump, we see the phenomenon that occurs flicker after liquid crystal display screen is hacked earlier again usually, the ac dump that Here it is claims in the industry dodges the screen phenomenon, this screen flicker can cause damage to the fluorescent tube of liquid crystal display screen, and shorten its useful life.Through research and analysis, the reason that occurs sudden strain of a muscle screen phenomenon when ac dump is as follows:
As everybody knows, the interface end of the backlight circuit of LCD screen contains power supply and switching signal (BKLON) two input pins usually, with power supply is example with 24V, when liquid crystal TV set was worked, the operating voltage that can obtain one+24V on the power supply pin offered liquid crystal display screen, at this moment, under the effect of the micro-controller instructions in backlight circuit, if obtain the high signal of telecommunication at ordinary times on the BKLON pin, backlight circuit is started working, and the 24V dc inverter is become driven lamp tube starting more than the 1KV; If when BKLON pin picked up signal is low level, backlight circuit will quit work, do not light fluorescent tube; Under the normal condition,, 24V power supply and switching signal BKLON there are certain sequential requirement, when promptly starting shooting, require the 24V power supply, but need the 24V power supply to be slower than the BKLON signal during shutdown prior to the BKLON signal in order not occur dodging the screen phenomenon.Yet when ac dump, the existing backlight circuit 24V power supply of just can not satisfying the demand is slower than the sequential requirement of BKLON signal, hacks the phenomenon of flicker more earlier so liquid crystal display screen takes place when producing ac dump.Its reason is: will thoroughly cut off the power supply of television set behind the ac dump, but because the electric capacity in the power circuit stores certain electric energy, can make backlight circuit work on, 24V voltage on electric capacity drops to when keeping the required lower critical operating voltage of backlight circuit work and just quits work automatically, yet just in this out-of-work moment, the stored energy of inductance element can charge to electric capacity again in the power circuit, its voltage is risen to once more above the lower critical operating voltage, and during this time, if the signal on the BKLON pin still is in high level state, backlight circuit is started working once more light fluorescent tube, thereby cause screen flicker.
The utility model content:
In order to eliminate above-mentioned sudden strain of a muscle screen phenomenon, prolong the useful life of liquid crystal display screen, the utility model provides a kind of screen flicker appears in liquid crystal TV set when ac dump control circuit that is used to eliminate, by this control circuit being arranged on the mode of the interface front end of backlight circuit, make at the signal of exporting to behind the ac dump on the switching signal pin of backlight circuit and maintain low level state, occur dodging the purpose of design of screen when realizing solving ac dump.Its technical scheme is as follows:
A kind ofly be used to eliminate screen flicker appears in liquid crystal TV set when ac dump control circuit, this control circuit is by a positive-negative-positive triode and a NPN type triode, and three diodes, two capacitors, some resistors connect and compose, the base stage of described positive-negative-positive triode is connected with power supply insertion interface after connecting series connection one resistance, emitter is connected back ground connection on the one hand with a resistance, and this dropping resistor is parallel with a bypass capacitor; Connect successively on the other hand and insert interface with aforementioned power source behind two switching diodes and the resistance and be connected; Collector electrode is connected behind another switching diode and one the tunnel to be connected ground connection behind the capacitor, connect and be connected with the base stage of NPN type triode behind the resistance in another road, be connected with a resistance between the grounded emitter of NPN type triode and emitter and base stage, its collector electrode links to each other with a switching signal input interface, during use, switching signal (BKLON) pin in the backlight circuit interface end of the switching signal input interface described in this circuit and available liquid crystal screen is connected, and described power supply inserts the interior power supply pin of backlight circuit interface end that interface and available liquid crystal shield and is connected.
Through after the above-mentioned connection, when carrying out ac dump, just can guarantee that the stored energy of inductance element charges to electric capacity in power circuit, its voltage is risen under the state above the lower critical operating voltage once more, signal on the BKLON pin still is in a low level state, thereby avoided backlight circuit to work once more lighting the fluorescent tube in the liquid crystal display screen, produced and dodge the screen phenomenon.
Advantage of the present utility model with good effect is: this practicality is by being connected control circuit on the switching signal input interface of backlight circuit, this control circuit can be when the LCD TV ac dump, the switching signal that is input to backlight circuit is remained on low level state a period of time, thereby the electric charge of avoiding discharging on the energy-storage travelling wave tube electric capacity and inductance in the circuit impacts backlight circuit, the screen flicker problem that has occurred when effectively having solved the LCD TV ac dump is to playing a positive role the useful life that prolongs liquid crystal display screen.
Description of drawings:
Fig. 1 is the control circuit of screen flicker appears in liquid crystal TV set when ac dump the circuit theory diagrams that are used to eliminate described in the utility model.
Embodiment:
The utility model is described in more detail below in conjunction with the drawings and specific embodiments.
As shown in Figure 1, describedly be used to eliminate screen flicker appears in liquid crystal TV set when ac dump control circuit, by a positive-negative-positive triode V1 and a NPN type triode V2 and three diode D1, D2, D3, two capacitor C1, C2, some resistors connect and compose, its circuit feature is: the base stage of described positive-negative-positive triode V1 is connected with power supply insertion interface a after connecting series connection one dropping resistor R2, emitter is connected back ground connection on the one hand with a dropping resistor R3, and this dropping resistor R3 is parallel with a bypass capacitor C1; Once connect on the other hand and insert interface a with aforementioned power source behind two switching diode D2, D1 and the dropping resistor R1 and be connected; Collector electrode is connected behind another switching diode D3 and one the tunnel to be connected ground connection behind the capacitor C2, connect and be connected with the base stage of NPN type triode V2 behind the dropping resistor R6 in another road, the grounded emitter of triode V2, and be connected with a resistance R 7 between emitter and base stage, its collector electrode links to each other with a switching signal input interface b.
During use, switching signal (BKLON) pin in the backlight circuit interface end of the switching signal input interface b described in this control circuit and available liquid crystal screen is connected, and described power supply inserts the interior power supply pin of backlight circuit interface end that interface a and available liquid crystal shield and is connected.After the connection, the back of just effectively avoiding shutting down when carrying out alternating-current switch takes place to dodge the phenomenon of shielding, and its operation principle is as follows:
When the television set operate as normal, capacitor C1 obtains charging, voltage is greatly about about+22.6v, the emitter voltage of triode V1 is lower than base voltage, triode V1 is in cut-off state, thereby triode V2 also is in cut-off state, that is to say that this moment, described control circuit was not worked, and after having carried out the ac dump operation, power supply inserts interface a and will lose+24 operating voltage, but, can cause this because the electric capacity in the power circuit stores the cause of certain electric energy+24V voltage is not to disappear immediately, but a process that descends is gradually arranged, be lower than on the C1 when dropping to+during 22.6v, triode V1 enters conducting state, so lead triode V2 also to enter conducting state, and the conducting of V2 must make its collector electrode become low level, has satisfied the sequential requirement of aforementioned relevant shutdown.
Claims (2)
1. be used to eliminate screen flicker appears in liquid crystal TV set when ac dump control circuit, it is characterized in that: this control circuit is by a positive-negative-positive triode and a NPN type triode, and three diodes, two capacitors, some resistors connect and compose, the base stage of described positive-negative-positive triode V1 connects series connection one resistance R 2 backs and is connected with power supply insertion interface a, emitter is connected back ground connection on the one hand with a resistance R 3, and this dropping resistor R3 is parallel with a bypass capacitor C1; Connect successively on the other hand two switching diode D2, D1 is connected with aforementioned power source insertion interface a with a resistance R 1 back; Collector electrode is connected behind another switching diode D3 and one the tunnel to be connected ground connection behind the capacitor C2, a resistance R 6 back of connecting, another road is connected with the base stage of NPN type triode V2, be connected with a resistance R 7 between the grounded emitter of NPN type triode V2 and emitter and base stage, its collector electrode links to each other with a switching signal input interface b.
2. be used to eliminate screen flicker appears in liquid crystal TV set when ac dump control circuit, it is characterized in that: during use, switching signal pin in the backlight circuit interface end of described switching signal input interface b and available liquid crystal screen is connected, and described power supply inserts the interior power supply pin of backlight circuit interface end that interface a and available liquid crystal shield and is connected.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011200964808U CN202068494U (en) | 2011-04-02 | 2011-04-02 | Control circuit used for eliminating screen flash occurring in AC shutdown of liquid crystal display television |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011200964808U CN202068494U (en) | 2011-04-02 | 2011-04-02 | Control circuit used for eliminating screen flash occurring in AC shutdown of liquid crystal display television |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202068494U true CN202068494U (en) | 2011-12-07 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011200964808U Expired - Fee Related CN202068494U (en) | 2011-04-02 | 2011-04-02 | Control circuit used for eliminating screen flash occurring in AC shutdown of liquid crystal display television |
Country Status (1)
| Country | Link |
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| CN (1) | CN202068494U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107255947A (en) * | 2017-06-22 | 2017-10-17 | 青岛海信电器股份有限公司 | Display device and its liquid crystal display backlight sequential control circuit |
-
2011
- 2011-04-02 CN CN2011200964808U patent/CN202068494U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107255947A (en) * | 2017-06-22 | 2017-10-17 | 青岛海信电器股份有限公司 | Display device and its liquid crystal display backlight sequential control circuit |
| CN107255947B (en) * | 2017-06-22 | 2019-08-23 | 青岛海信电器股份有限公司 | Display device and its liquid crystal display backlight sequential control circuit |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C56 | Change in the name or address of the patentee | ||
| CP01 | Change in the name or title of a patent holder |
Address after: 528234, Guangdong, Foshan City, Nanhai District, Songgang pine summer Industrial Park Road Foundation Patentee after: Guangdong shengzhiyuan digital electronics Limited by Share Ltd Address before: 528234, Guangdong, Foshan City, Nanhai District, Songgang pine summer Industrial Park Road Foundation Patentee before: Guangdong Shengzhiyuan Digital Electronics Co., Ltd. |
|
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20111207 Termination date: 20140402 |