CN201388280Y - Spot suppressor and television having same - Google Patents
Spot suppressor and television having same Download PDFInfo
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- CN201388280Y CN201388280Y CN200920021295U CN200920021295U CN201388280Y CN 201388280 Y CN201388280 Y CN 201388280Y CN 200920021295 U CN200920021295 U CN 200920021295U CN 200920021295 U CN200920021295 U CN 200920021295U CN 201388280 Y CN201388280 Y CN 201388280Y
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Abstract
The utility model discloses a spot suppressor and a television having same, which comprises a first DC power source, a PNP triode, a first energy storage capacitor and a switch circuit, wherein a base electrode of the PNP triode is connected with the first DC power source, an emitter of the PNP triode is connected with the first energy storage capacitor while being connected with the cathode of a diode, and the emitter of the PNP triode is connected with the first DC power source through the anode of the diode; and the collector electrode of the PNP triode is connected with a control end of the switch circuit, and a switch passage of the switch circuit is arranged between an RGB signal terminal and the ground. The spot suppressor has simple structure, is easy to be realized, and can attain well suppression of the bright spots so as to improve the performance of the produce and the satisfactory of the user and to prolong the service life of a kinescope, and is applicable to the image output devices such as the CRT television or the CRT monitor adopting a cathode ray as a picture display part.
Description
Technical field
The utility model belongs to picture tube display device technical field, specifically, relates to a kind of off-spot or the electronic circuit of speck and television set with described shutdown spot suppressor eliminated when the picture tube display device shuts down.
Background technology
For present most TV users, also still use and adopt cathode-ray tube CRT (Cathode Ray Tubes, cathode ray tube) to receive, watch TV programme as the television set of view display spare.CRT TV needed drive signal when carrying out the image demonstration is R, G, the B analog signal of exporting after process decoding, the processing and amplifying.The decoding circuit of television set inside is to after handling by the decoding video signal that tuner receives, demodulation is exported, and generation and output R, G, B simulate small-signal; R, G, B simulation small-signal are exported to video amplifier circuit and carry out power amplification, and then generate three electron gun emitting electrons of R, G, B of high-power R, G, B analog signal driving picture tube, electron beam is beaten and demonstrate image on phosphor screen.
When the CRT TV shuts down, row field deflection circuit quits work, and anode high voltage, screen voltage, RGB drive signal can't disappear at once, and electron gun is not cooling fully also, still outside emitting electrons, these electronics are under not capable effect of electric field, accumulate in screen center, form bright spot or speck, not only influenced user's use, and the long-term use picture tube of also can burning, shorten useful life of CRT television set.
The utility model content
The utility model is in order to solve the problem that bright spot or speck can appear in existing CRT TV screen center when shutting down; a kind of simple in structure, obvious results shutdown spot suppressor is provided; with bright spot or the speck that thorough elimination shutdown moment screen center produces, realize effective protection to picture tube.
For solving the problems of the technologies described above, the utility model is achieved by the following technical solutions:
A kind of shutdown spot suppressor comprises first DC power supply, positive-negative-positive triode, first storage capacitor and a switching circuit; The base stage of described positive-negative-positive triode connects first DC power supply, and emitter connects first storage capacitor on the one hand, connects the negative electrode of a diode on the other hand, and connects first DC power supply by the anode of described diode; The collector electrode of described positive-negative-positive triode connects the control end of switching circuit, and the switch ways of described switching circuit is connected between rgb signal terminal and the ground.
Further, include a NPN type triode in described switching circuit, the base stage of described NPN type triode connects the collector electrode of positive-negative-positive triode, the grounded emitter of NPN type triode, and collector electrode connects the rgb signal terminal.
Wherein, the rgb signal input terminal that described rgb signal terminal can be a video amplifier circuit also can be the rgb signal lead-out terminal of video amplifier circuit.When display device shuts down, to be input to the rgb signal of video amplifier circuit or the rgb signal that video amplifier circuit amplifies output will be shorted to ground by the shutdown spot suppressor, with of the output of blocking-up rgb signal, reach the purpose of design of shutdown moment elimination screen bright spot or speck to picture tube.
Further again, described rgb signal terminal connects the anode of a switching diode, and connects the switch ways of switching circuit by the negative electrode of described switching diode.
Further again, in described shutdown spot suppressor, also include an electron beam that is connected the picture tube gate terminal and suppress circuit, comprise second DC power supply, second storage capacitor that is connected with described second DC power supply and the discharge resistance that is connected in parallel on the second storage capacitor two ends; The positive pole of described second storage capacitor connects second DC power supply, and negative pole connects the grid of picture tube on the one hand, connects the anode of catching diode on the other hand, and the minus earth by described catching diode.
Wherein, in order to realize that display device electric charge in second storage capacitor when shutting down can pass through the slow bleed off of discharge resistance, the resistance of described discharge resistance should guarantee enough big, preferably adopts resistance to design described electron beam inhibition circuit more than or equal to the discharge resistance of 10 megaohms.
Further, the negative pole of described second storage capacitor connects the anode of described catching diode by protective resistance, and further connects the grid of picture tube by filter circuit.
Based on above-mentioned shutdown spot suppressor structure; the utility model provides a kind of television set with described shutdown spot suppressor again; by on the rgb signal input terminal of the video amplifier circuit of television set inside or rgb signal lead-out terminal, connecting mainly by the positive-negative-positive triode; first storage capacitor and switching circuit are set up the shutdown cut-off circuit that forms; and connect described electron beam in the gate terminal of picture tube and suppress circuit; thereby can suppress the emission of electron beam from two aspects; with bright spot or the speck that thorough elimination television set shutdown moment screen center produces, realize effective protection to picture tube.
Compared with prior art, advantage of the present utility model and good effect are: shutdown spot suppressor of the present utility model is simple in structure, be easy to realize, can reach shutdown well and eliminate the effect of bright spot, speck, thereby the performance of product and user's satisfaction have been improved, prolonged the useful life of picture tube, be fit to be applied to adopt cathode ray tube as in the image output devices such as the CRT television set of view display spare or CRT monitor.
After reading the detailed description of the utility model execution mode in conjunction with the accompanying drawings, other characteristics of the present utility model and advantage will become clearer.
Description of drawings
Fig. 1 is the circuit theory diagrams of a kind of embodiment of the shutdown spot suppressor that proposes of the utility model;
Fig. 2 is the circuit theory diagrams of the another kind of embodiment of the shutdown spot suppressor that proposes of the utility model.
Embodiment
Below in conjunction with accompanying drawing embodiment of the present utility model is done explanation in further detail.
The utility model still continues divergent bundle in order to solve CRT display device electron gun in the picture tube when shutting down, these electronics accumulate in the problem that screen center forms bright spot or speck, two kinds of hardware circuit solutions that version is different are provided: a kind of is to adopt first storage capacitor, elements such as positive-negative-positive triode and switching circuit are set up the shutdown cut-off circuit that forms, when the CRT display device shuts down, the electric charge control positive-negative-positive triode and the connected switching circuit conducting that utilize first storage capacitor to store, thereby the circuit-formed RBG signal of CRT display device is shorted to ground, output with the blocking-up rgb signal, and then make the negative electrode of picture tube because of no drive signal emitting electrons not, play the effect of eliminating off-spot or speck; Another design is that the gate terminal (being the G1 electrode tip of picture tube) at picture tube connects by second storage capacitor, element such as discharge resistance and catching diode is set up the electron beam that forms and is suppressed circuit, when the CRT display device shuts down, to be stored in electric charge in second storage capacitor by the slow bleed off of the discharge resistance in parallel with it, and then apply negative dc voltage to the G1 of picture tube electrode, to suppress the electron amount that tube cathode emits, make the electron amount that arrives screen center significantly reduce, reach the purpose of design of eliminating off-spot or speck.
Two kinds of design circuits can use separately, also can use simultaneously.Using simultaneously can be more obvious so that suppress the effect of off-spot or speck, and the complete machine performance is more stable.
Be example with the CRT television set below, elaborate the concrete composition structure and the operation principle thereof of described shutdown spot suppressor by a specific embodiment.
Embodiment one, and present embodiment realizes eliminating the purpose of off-spot or speck by design shutdown cut-off circuit.Referring to shown in Figure 1, the shutdown cut-off circuit of present embodiment mainly comprises first DC power supply, the first storage capacitor C901, diode VD904, positive-negative-positive triode V511 and the parts such as switching circuit that formed by NPN type triode V501 and peripheral circuit establishment thereof.Wherein, first DC power supply can adopt power circuit voltage stabilizing output+12V or+DC power supply forms such as 18V.Present embodiment with+the 12V DC power supply is that example is set forth.Described+12 DC power supply connect the base stage of positive-negative-positive triode V511 on the one hand by resistance R 521; The positive pole that connects the first storage capacitor C901 on the other hand by diode VD904, and then be connected with the emitter of positive-negative-positive triode V511.The minus earth of the described first storage capacitor C901.For when television set shuts down, the electric charge of guaranteeing to be stored among the first storage capacitor C901 can accurately discharge according to predetermined direction, and can not fall by+rapid the bleed off of 12V dc power supply terminal, the anode of described diode VD904 is connected with+12V dc power supply terminal, negative electrode is connected with the positive pole of the first storage capacitor C901, when television set shuts down, utilize the reverse blocking state of diode VD904, block electric charge among the first storage capacitor C901 to the circulation of+12V dc power supply terminal.
The collector electrode of described positive-negative-positive triode V511 connects the base stage of NPN type triode V501 on the one hand by resistance R 511, on the other hand by resistance R 501 ground connection.NPN type triode V501 and resistance R 511, R501 constitute switching circuit, its grounded emitter, and collector electrode connects the terminal R/G/B that is used to transmit rgb signal in the television set.For the shutdown cut-off circuit that makes present embodiment and the RGB circuit in the television set can be realized effective isolation in television boot-strap and normal course of operation, the collector electrode of described NPN type triode V501 is connected rgb signal terminal R/G/B in the television set by switching diode VD901.Wherein, the negative electrode of switching diode VD901 connects the collector electrode of NPN type triode V501, and anode connects rgb signal terminal R/G/B.
In the present embodiment, described rgb signal terminal R/G/B can be the rgb signal lead-out terminal of television set inner decoding chip, or the rgb signal input terminal of video amplifier circuit, also can be rgb signal lead-out terminal of video amplifier circuit etc.Present embodiment is the operation principle that example is specifically set forth this shutdown cut-off circuit with the rgb signal input terminal of video amplifier circuit only.
After the television boot-strap operation, by television power circuit voltage stabilizing output+the 12V DC power supply charges to the first storage capacitor C901 by diode VD904 (conducting voltage of supposing diode VD904 is Vfm), makes that voltage reaches 12V on the storage capacitor C901 that wins.At this moment, positive-negative-positive triode V511 is in cut-off state owing to its emitter voltage equals its base voltage; The base stage of NPN type triode V501 is by resistance R 501 ground connection, and current potential is low, thereby makes also remain off state of NPN type triode V501.At this moment, switching diode VD901 oppositely ends, and stops rgb signal to flow through this shutdown cut-off circuit, thereby the cut-off circuit of guaranteeing to shut down can not produce any influence to the original circuit of television set in television set startup and course of normal operation.
When television set shuts down, shutting down moment, described+12V DC power supply reduces rapidly, thereby make the base potential of positive-negative-positive triode V511 also reduce rapidly thereupon, and the first storage capacitor C901 still can keep+12V voltage in the moment of shutting down, thereby caused positive-negative-positive triode V511 saturation conduction (CE of triode V511 economize on electricity is pressed and is Vce when supposing conducting).At this moment, the electric charge that the first storage capacitor C901 discharges is by the positive-negative-positive triode V511 of conducting, under the dividing potential drop effect of resistance R 511 and R501, the base potential of NPN type triode V501 is raise, and then control NPN type triode V501 saturation conduction, drag down its collector potential, make switching diode VD901 forward conduction.So, the first storage capacitor C901 is by positive-negative-positive triode V511, resistance R 511 and NPN type triode V501 slowly discharge over the ground, the rgb signal of input video amplifying circuit is collector electrode, the grounded emitter of switching diode VD901 and the NPN type triode V501 by conducting then, rgb signal is rapidly disappeared, and then make the negative electrode of picture tube, thereby avoid when television set shuts down screen center to produce the phenomenon of bright spot or speck because of no drive signal emitting electrons not.
In the present embodiment, the described first storage capacitor C901 can specifically select for use electrochemical capacitor to realize; Positive-negative-positive triode V511 can adopt the alternative realizations of switch unit such as P channel MOS tube; Switching circuit also can adopt except that NPN type triode V501 other to have circuits built forms such as the components and parts of on-off action or integrated chip and substitute and realize that present embodiment does not specifically limit this.
Embodiment two, and present embodiment adopts electron beam to suppress the purpose of design that circuit realizes eliminating off-spot or speck.Referring to shown in Figure 2, mainly comprise second DC power supply, the second storage capacitor C533, the discharge resistance R535 that is connected in parallel on the second storage capacitor C533 two ends and catching diode VD531 parts such as (conducting voltage of supposing catching diode VD531 are Vfm).Wherein, second DC power supply can adopt television power circuit conversion output+190V or+high-voltage DC power supplies such as 200V are second storage capacitor C533 charging accumulation of energy.Present embodiment with+the 200V DC power supply is that example is set forth.Described+200V DC power supply connects the positive pole of the second storage capacitor C533, and the negative pole that passes through the second storage capacitor C533 connects protective resistance R536, and then connect the anode of catching diode VD531, the minus earth of catching diode VD531 on the one hand by protective resistance R536; The grid that connects picture tube on the other hand by filter circuit, i.e. G1 electrode.
When the television set operate as normal ,+200V DC power supply is charged to the second storage capacitor C533, makes the voltage at the second storage capacitor C533 two ends be (200V-Vfm), and the G1 electrode voltage of picture tube is clamped at Vfm by catching diode VD531.Because Vfm is generally very little, usually less than 1V, therefore influence is very little concerning the G1 electrode, can ignore, thereby when being implemented in the television set operate as normal, this electron beam suppresses circuit other partial circuits of television set are not produced any influence.
When television set shuts down, to shut down moment ,+200V DC power supply rapidly disappears, and the electric charge that is stored among the second storage capacitor C533 passes through discharge resistance R535 bleed off.In order to realize the slow bleed off of electric charge, the resistance of described discharge resistance R535 should guarantee enough big, need select for use resistance to design more than or equal to the discharge resistance of 10 megohms usually.Because the discharge of the second storage capacitor C533, the direct voltage of the negative pole generation pact-200V that makes at the second storage capacitor C533, this voltage is added on the G1 electrode of picture tube, the electron amount that the cathode emission of meeting inhibition picture tube is come out, make the electron amount that arrives screen center reduce greatly, thereby play the effect of eliminating off-spot or speck.
In the present embodiment, the described second storage capacitor C533 can adopt a high-power electrolysis electric capacity to realize.Described filter circuit can adopt RC filter circuit or other filter network form that is composed in parallel by resistance R 537 and capacitor C 528, comes the formed high-voltage pulse of the inner sparking of filtering picture tube, with the electron beam inhibition circuit of protection present embodiment.Protective resistance R536 can prevent+high-voltage pulse that seals in the 200V DC power supply disturbs the damage that other circuit are caused.
Embodiment three, and present embodiment adopts the mode that shutdown cut-off circuit and electron beam inhibition circuit are set on television set inner decoding plate simultaneously thoroughly to block the tube cathode divergent bundle in order to make the effect that suppresses off-spot or speck more obvious.Wherein, the shutdown cut-off circuit can adopt as shown in Figure 1 circuit form to be connected the input of video amplifier circuit, shut down moment at television set, directly block the emission of tube cathode by the RGB small-signal that will be input to video amplifier circuit with being shorted to, thereby play the effect of eliminating off-spot or speck.Electron beam suppresses circuit and can adopt as shown in Figure 2 circuit form to be connected the G1 electrode tip of picture tube, when television set shuts down, by applying to the G1 of picture tube electrode-direct voltage of 200V, thereby suppress tube cathode electrons emitted quantity, reach the purpose of design of further elimination screen center's bright spot or speck.
Certainly; above-mentioned explanation is not to be to restriction of the present utility model; the utility model also is not limited in above-mentioned giving an example, and variation, remodeling, interpolation or replacement that those skilled in the art are made in essential scope of the present utility model also should belong to protection range of the present utility model.
Claims (10)
1, a kind of shutdown spot suppressor is characterized in that: comprise first DC power supply, positive-negative-positive triode, first storage capacitor and a switching circuit; The base stage of described positive-negative-positive triode connects first DC power supply, and emitter connects first storage capacitor on the one hand, connects the negative electrode of a diode on the other hand, and connects first DC power supply by the anode of described diode; The collector electrode of described positive-negative-positive triode connects the control end of switching circuit, and the switch ways of described switching circuit is connected between rgb signal terminal and the ground.
2, shutdown spot suppressor according to claim 1, it is characterized in that: in described switching circuit, include a NPN type triode, the base stage of described NPN type triode connects the collector electrode of positive-negative-positive triode, the grounded emitter of NPN type triode, and collector electrode connects the rgb signal terminal.
3, shutdown spot suppressor according to claim 1, it is characterized in that: described rgb signal terminal connects the anode of a switching diode, and connects the switch ways of switching circuit by the negative electrode of described switching diode.
4, shutdown spot suppressor according to claim 1 is characterized in that: the rgb signal input terminal that described rgb signal terminal is a video amplifier circuit or the rgb signal lead-out terminal of video amplifier circuit.
5, according to each described shutdown spot suppressor in the claim 1 to 4, it is characterized in that: in described shutdown spot suppressor, also include an electron beam that is connected the picture tube gate terminal and suppress circuit, comprise second DC power supply, second storage capacitor that is connected with described second DC power supply and the discharge resistance that is connected in parallel on the second storage capacitor two ends; The positive pole of described second storage capacitor connects second DC power supply, and negative pole connects the grid of picture tube on the one hand, connects the anode of catching diode on the other hand, and the minus earth by described catching diode.
6, shutdown spot suppressor according to claim 5, it is characterized in that: the resistance of described discharge resistance is more than or equal to 10 megaohms.
7, shutdown spot suppressor according to claim 5 is characterized in that: the negative pole of described second storage capacitor connects the anode of described catching diode by protective resistance, and further connects the grid of picture tube by filter circuit.
8, a kind of television set comprises first DC power supply, second DC power supply, rgb signal terminal and picture tube by power circuit voltage stabilizing output; It is characterized in that: on described rgb signal terminal, be connected with a shutdown cut-off circuit, comprise positive-negative-positive triode, first storage capacitor and a switching circuit; The base stage of described positive-negative-positive triode connects first DC power supply, and emitter connects first storage capacitor on the one hand, connects the negative electrode of a diode on the other hand, and connects first DC power supply by the anode of described diode; The collector electrode of described positive-negative-positive triode connects the control end of switching circuit, and the switch ways of described switching circuit is connected between rgb signal terminal and the ground.
9, television set according to claim 8 is characterized in that: described rgb signal terminal is the rgb signal input terminal of television set interior video amplifying circuit or the rgb signal lead-out terminal of video amplifier circuit.
10, television set according to claim 8, it is characterized in that: the gate terminal at described picture tube is connected with electron beam inhibition circuit, comprises second storage capacitor that is connected with described second DC power supply and the discharge resistance that is connected in parallel on the second storage capacitor two ends; The positive pole of described second storage capacitor connects second DC power supply, and negative pole connects the grid of picture tube on the one hand, connects the anode of catching diode on the other hand, and the minus earth by described catching diode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200920021295U CN201388280Y (en) | 2009-04-17 | 2009-04-17 | Spot suppressor and television having same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200920021295U CN201388280Y (en) | 2009-04-17 | 2009-04-17 | Spot suppressor and television having same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201388280Y true CN201388280Y (en) | 2010-01-20 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN200920021295U Expired - Fee Related CN201388280Y (en) | 2009-04-17 | 2009-04-17 | Spot suppressor and television having same |
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| Country | Link |
|---|---|
| CN (1) | CN201388280Y (en) |
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2009
- 2009-04-17 CN CN200920021295U patent/CN201388280Y/en not_active Expired - Fee Related
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Legal Events
| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20100120 Termination date: 20120417 |