CN201601737U - Video amplifying circuit - Google Patents
Video amplifying circuit Download PDFInfo
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- CN201601737U CN201601737U CN2010201371504U CN201020137150U CN201601737U CN 201601737 U CN201601737 U CN 201601737U CN 2010201371504 U CN2010201371504 U CN 2010201371504U CN 201020137150 U CN201020137150 U CN 201020137150U CN 201601737 U CN201601737 U CN 201601737U
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Abstract
The utility model embodiment provides a video amplifying circuit and relates to a field of a correlated household electrical appliance having video output. The video amplifying circuit can realize different DC bias and feedback matching so as to realize different amplification times and ensure the input signal with different video signals to achieve ideal output requirement. The video amplifying circuit includes: a DC bias branch circuit, an amplification branch circuit and a control branch circuit; one end of the control branch circuit is connected with a control signal and the other end is connected with the DC bias branch circuit and the amplification branch circuit; the control branch circuit controls the DC bias branch circuit to select a DC bias point and controls the amplification branch circuit to do feedback matching. The utility model is used for products having video amplification function such as set-top box, DVD, TV and the like.
Description
Technical field
The utility model relates to the associated appliance apparatus field with video output, relates in particular to a kind of video amplifier circuit.
Background technology
For video amplifier circuit, the general circuit structure that adopts as shown in Figure 1 of prior art, realization is to the direct current biasing and the feedback coupling of vision signal, particularly, the direct current biasing branch road that utilizes variable resistor R1 and R2 to constitute is determined the direct current biasing point, and utilizes the secondary that has triode V1 and V2 to constitute to amplify branch road and realize the feedback coupling.
When realizing the technical solution of the utility model, the inventor finds that there is following problem at least in the video amplifier circuit of prior art: be difficult to guarantee consistent product (as changing with the signal standard) for video input signals CVBSOut amplitude, original video amplifier circuit can only be compromised, make different vision signal input signals satisfy standard in the output of terminal as far as possible, but because this video amplifier circuit can not be adjusted direct current biasing and feedback coupling flexibly, multiplication factor is unique, therefore still there is deviation to a certain extent in the signal of its output, can not guarantee that different vision signal input signals all reaches desirable output requirement.
The utility model content
Technical problem to be solved in the utility model is to provide a kind of video amplifier circuit, can realize different direct current biasings and feedback coupling, thereby realize different multiplication factors, guarantees that different video signal input signal all can reach desirable output requirement.
In order to solve the problems of the technologies described above, the utility model video amplifier circuit adopts following technical scheme:
A kind of video amplifier circuit, comprise: direct current biasing branch road, amplification branch road and control branch road, one end connection control signal of described control branch road, the other end connects described direct current biasing branch road and described amplification branch road, described control branch road is controlled described direct current biasing branch road and is selected the direct current biasing point, and controls described amplification branch road feedback coupling.
Described direct current biasing branch road comprises: first resistance and second resistance,
One end of described first resistance connects video signal input terminal, and connects described second resistance, and the other end connects supply voltage;
One end of described second resistance connects described video signal input terminal, and connects described first resistance, other end ground connection.
Described direct current biasing branch road also comprises: first electric capacity,
One end of described first electric capacity connects supply voltage, other end ground connection.
Described amplification branch road comprises: the 3rd resistance, the 4th resistance, the 5th resistance, the 6th resistance, first triode and second triode,
One end of described the 3rd resistance connects supply voltage, and the other end connects the collector electrode of described first triode;
One end of described the 4th resistance connects the emitter of described first triode, other end ground connection;
One end of described the 5th resistance connects the emitter of described first triode, and the other end connects described the 6th resistance;
One end of described the 6th resistance connects described the 5th resistance, and the other end connects the collector electrode of described second triode, and connects VT;
The base stage of described first triode connects described video signal input terminal, and collector electrode connects the base stage of described the 3rd resistance and second triode, and emitter connects described the 4th resistance and the 5th resistance;
The base stage of described second triode connects the collector electrode of described the 3rd resistance and described first triode, and collector electrode connects described the 6th resistance and described VT, and emitter connects described supply voltage.
Described amplification branch road also comprises: the 7th resistance,
One end of described the 7th resistance connects the collector electrode and described the 6th resistance of described second triode, and the other end connects described VT.
Described control branch road comprises: the 8th resistance, the 9th resistance, the 3rd triode and the 4th triode,
One end of described the 8th resistance connects the base stage of described video signal input terminal, described first resistance, described second resistance and described first triode, and the other end connects the collector electrode of described the 3rd triode;
One end of described the 9th resistance connects the emitter of described the 4th resistance, described the 5th resistance and described first triode, and the other end connects the collector electrode of described the 4th triode;
The base stage of described the 3rd triode connects first signal input end, and collector electrode connects described the 8th resistance, grounded emitter;
The base stage of described the 4th triode connects second signal input end, and collector electrode connects described the 8th resistance, grounded emitter.
Described control branch road also comprises: the tenth resistance and the 11 resistance,
One end of described the tenth resistance connects described first signal input end, and the other end connects the base stage of described the 3rd triode;
One end of described the 11 resistance connects described second signal input end, and the other end connects the base stage of described the 4th triode.
Also comprise: second electric capacity that is connected described video signal input terminal.
Also comprise: the 3rd electric capacity and the piezo-resistance that are connected described VT.
The control signal of described first signal input end and the input of described second signal input end is same general input/output signal, perhaps is different general input/output signals.
In the technical scheme of the utility model embodiment, increase the control branch road by input at existing video amplifier circuit, can realize different direct current biasings and feedback coupling, thereby realize different multiplication factors, make different video input signals all can reach desirable vision signal output requirement, avoid occurring the perfection use that nonstandard situation influences receiving equipment.
Description of drawings
In order to be illustrated more clearly in the utility model embodiment or technical scheme of the prior art, the accompanying drawing of required use is done to introduce simply in will describing embodiment below, apparently, accompanying drawing in describing below only is embodiment more of the present utility model, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain other accompanying drawing according to these accompanying drawings.
Fig. 1 is the electrical block diagram of prior art video amplifier circuit;
Fig. 2 is the electrical block diagram of the video amplifier circuit of the utility model embodiment.
Description of reference numerals:
The 1-base stage; The 2-collector electrode; The 3-emitter.
Embodiment
The utility model embodiment provides a kind of video amplifier circuit, can realize different direct current biasings and feedback coupling, thereby realize different multiplication factors, guarantees that different video signal input signal all can reach desirable output requirement.
Below in conjunction with accompanying drawing the utility model embodiment video amplifier circuit is described in detail.
The video amplifier circuit that the utility model embodiment provides is applied to comprise the associated appliance equipment of video output, such as set-top box, DVD, TV etc.In order to be difficult to guarantee consistent product (as changing) at different video input signals amplitudes with the signal standard, realize different direct current biasings and feedback coupling, thereby realize different multiplication factors, make input signal all reach desirable output requirement, the video amplifier circuit that the utility model embodiment provides comprises: the direct current biasing branch road, amplify branch road and control branch road, one end connection control signal of control branch road, the other end connects the direct current biasing branch road and amplifies branch road, control branch road control direct current biasing branch road is selected the direct current biasing point, and branch road feedback coupling is amplified in control.
In the technical scheme of the utility model embodiment, increase the control branch road by input at existing video amplifier circuit, can realize different direct current biasings and feedback coupling, thereby realize different multiplication factors, make different video input signals all can reach desirable vision signal output requirement, avoid occurring the perfection use that nonstandard situation influences receiving equipment.
Particularly, supply voltage+12V can adopt+12V or+jumping of 5V selects voltage, in the present embodiment, is preferably+12V, as shown in Figure 2, the direct current biasing branch road comprises: first resistance R 1 and second resistance R 2,
One end of first resistance R 1 connects video signal input terminal CVBSOut, and connects second resistance R 2, and the other end connects supply voltage+12V; One end of second resistance R 2 connects video signal input terminal CVBSOut, and connects first resistance R 1, other end ground connection.
Further, this direct current biasing branch road also comprises: first capacitor C 1, the effect of this electric capacity is a power filter.One end of first capacitor C 1 connects supply voltage+12V, and other end ground connection in the present embodiment, is preferably the electric capacity of 0.1uF.
Further, amplify branch road and comprise that secondary amplifies, wherein amplification has constituted feedback to one-level in the secondary amplification, specifically comprises: the 3rd resistance R 3, the 4th resistance R 4, the 5th resistance R 5, the 6th resistance R 6, the first triode V1 and the second triode V2,
One end of the 3rd resistance R 3 connects supply voltage+12V, and the other end connects the collector electrode 2 of the first triode V1; One end of the 4th resistance R 4 connects the emitter 3 of the first triode V1, other end ground connection; One end of the 5th resistance R 5 connects the emitter 3 of the first triode V1, and the other end connects the 6th resistance R 6; One end of the 6th resistance R 6 connects the 5th resistance R 5, and the other end connects the collector electrode 2 of the second triode V2, and connects VT Scart_AV VOUT; The base stage 1 of the first triode V1 connects video signal input terminal CVBSOut, and collector electrode 2 connects the base stage 1 of the 3rd resistance R 3 and the second triode V2, and emitter 3 connects the 4th resistance R 4 and the 5th resistance R 5; The base stage 1 of the second triode V2 connects the collector electrode 2 of the 3rd resistance R 3 and the first triode V1, and collector electrode 2 connects the 6th resistance R 6 and VT Scart_AVVOUT, and emitter 3 connects supply voltage+12V.
Again further, amplifying branch road also comprises: the 7th resistance R 7, its effect is a dividing potential drop, so that be complementary with output and next stage equipment.One end of the 7th resistance R 7 connects collector electrode 2 and the 6th resistance R 6 of the second triode V2, and the other end connects VT Scart_AV VOUT.
Further, the control branch road comprises: the 8th resistance R 8, the 9th resistance R 9, the 3rd triode V3 and the 4th triode V4,
One end of the 8th resistance R 8 connects the base stage 1 of video signal input terminal CVBSOut, first resistance R 1, second resistance R 2 and the first triode V1, and the other end connects the collector electrode 2 of the 3rd triode V3; One end of the 9th resistance R 9 connects the emitter 3 of the 4th resistance R 4, the 5th resistance R 5 and the first triode V1, and the other end connects the collector electrode 2 of the 4th triode V4; The base stage 1 of the 3rd triode V3 connects first signal input end, and collector electrode 2 connects the 8th resistance R 8, emitter 3 ground connection; The base stage 1 of the 4th triode V4 connects second signal input end, and collector electrode 2 connects the 8th resistance R 8, emitter 3 ground connection.
Again further, the control branch road also comprises: the tenth resistance R 10 and the 11 resistance R 11, its effect is a current limliting, to avoid when control signal is high level, is added in the overtension on the 3rd triode V3 and the 4th triode V4 base stage.One end of the tenth resistance R 10 connects first signal input end, and the other end connects the base stage 1 of the 3rd triode V3; One end of the 11 resistance R 11 connects second signal input end, and the other end connects the base stage 1 of the 4th triode V4.
Again further, this video amplifier circuit also comprises: be connected second capacitor C 2 of video signal input terminal CVBSOut, play the effect of isolated DC.
Again further, this video amplifier circuit also comprises: be connected the 3rd capacitor C 3 and the piezo-resistance R12 of VT Scart_AVVOUT, the 3rd capacitor C 3 plays the effect of filtering, has reduced the frequency distortion of vision signal effectively, in the present embodiment, be preferably the electric capacity of 560PF; The piezo-resistance R12 of ground connection can eliminate impulse disturbances, plays the effect of electrostatic defending.
In the present embodiment, described resistance (R1, R2, R2, R4, R5, R6, R7, R8, R9, R10, R11) is variable resistor, and the preferred specified resistance of resistance shown in Fig. 2: R1 is 100K Ω; R2 is 27K Ω; R3 is 330 Ω; R4 is 150 Ω; R5 is 220 Ω; R6 is 220 Ω; R7 is 75 Ω; R8 is 27K Ω; R9 is 47 Ω; R10 is 4.7K Ω; R11 is 4.7K Ω.
The video amplifier circuit that present embodiment provides realizes that the operation principle of different direct current biasings and feedback coupling is as follows:
Control signal with first signal input end and the input of second signal input end is that same general input/output signal GAIN_SW is an example.
When general input/output signal GAIN_SW is high level, the 3rd triode V3 conducting, the 4th triode V4 conducting, circuit shown in Figure 2 is equal to the 8th resistance R 8 and 2 parallel connections of second resistance R, with first resistance R, 1 common formation direct current biasing branch road, determine the direct current biasing point; And the 9th resistance R 9 is in parallel with 4 formation of the 4th resistance R, and the resistance of the feedback build-out resistor that whole feedback match circuit constitutes is: 1+ (R6+R5)/R4 ∪ R9, thus determined multiplication factor.
When general input/output signal GAIN_SW was low level, the 3rd triode V3 ended, and the 4th triode V4 ends, and circuit shown in Figure 2 is equal to second resistance R 2 and first resistance R, 1 common formation direct current biasing branch road, determines the direct current biasing point; And, the 9th resistance R 9 infinities, the 4th resistance R 4 over the ground, the resistance of the feedback build-out resistor that whole feedback match circuit constitutes is: 1+ (R6+R5)/R4, thereby determined multiplication factor.
Further, first signal input end can also be different general input/output signal GAIN_SW with the control signal of second signal input end input, promptly first signal input end is connected different general input/output signal GAIN_SW signal inputs with second signal input end, can be (high by four kinds of input states of first signal input end and second signal input end, just, low high and low), realize different direct current biasings and feedback coupling, thereby realize different multiplication factors, guarantee that different video signal input signal all can reach desirable output requirement.
In the technical solution of the utility model, increase the control branch road by input at existing video amplifier circuit, promptly utilize two triode actions of general input/output signal GAIN_SW control, when input/output signal GAIN_SW is respectively high or low, can realize different direct current biasings and feedback coupling, thereby realize different multiplication factors, make different video input signals all can reach desirable vision signal output requirement, avoid occurring the perfection use that nonstandard situation influences receiving equipment.
The above; it only is embodiment of the present utility model; but protection range of the present utility model is not limited thereto; anyly be familiar with those skilled in the art in the technical scope that the utility model discloses; can expect easily changing or replacing, all should be encompassed within the protection range of the present utility model.Therefore, protection range of the present utility model should be as the criterion with the protection range of described claim.
Claims (10)
1. video amplifier circuit, it is characterized in that, comprise: direct current biasing branch road, amplification branch road and control branch road, one end connection control signal of described control branch road, the other end connects described direct current biasing branch road and described amplification branch road, described control branch road is controlled described direct current biasing branch road and is selected the direct current biasing point, and controls described amplification branch road feedback coupling.
2. video amplifier circuit according to claim 1 is characterized in that,
Described direct current biasing branch road comprises: first resistance and second resistance,
One end of described first resistance connects video signal input terminal, and connects described second resistance, and the other end connects supply voltage;
One end of described second resistance connects described video signal input terminal, and connects described first resistance, other end ground connection.
3. video amplifier circuit according to claim 2 is characterized in that,
Described direct current biasing branch road also comprises: first electric capacity,
One end of described first electric capacity connects supply voltage, other end ground connection.
4. video amplifier circuit according to claim 3 is characterized in that,
Described amplification branch road comprises: the 3rd resistance, the 4th resistance, the 5th resistance, the 6th resistance, first triode and second triode,
One end of described the 3rd resistance connects supply voltage, and the other end connects the collector electrode of described first triode;
One end of described the 4th resistance connects the emitter of described first triode, other end ground connection;
One end of described the 5th resistance connects the emitter of described first triode, and the other end connects described the 6th resistance;
One end of described the 6th resistance connects described the 5th resistance, and the other end connects the collector electrode of described second triode, and connects VT;
The base stage of described first triode connects described video signal input terminal, and collector electrode connects the base stage of described the 3rd resistance and second triode, and emitter connects described the 4th resistance and the 5th resistance;
The base stage of described second triode connects the collector electrode of described the 3rd resistance and described first triode, and collector electrode connects described the 6th resistance and described VT, and emitter connects described supply voltage.
5. video amplifier circuit according to claim 4 is characterized in that,
Described amplification branch road also comprises: the 7th resistance,
One end of described the 7th resistance connects the collector electrode and described the 6th resistance of described second triode, and the other end connects described VT.
6. video amplifier circuit according to claim 5 is characterized in that,
Described control branch road comprises: the 8th resistance, the 9th resistance, the 3rd triode and the 4th triode,
One end of described the 8th resistance connects the base stage of described video signal input terminal, described first resistance, described second resistance and described first triode, and the other end connects the collector electrode of described the 3rd triode;
One end of described the 9th resistance connects the emitter of described the 4th resistance, described the 5th resistance and described first triode, and the other end connects the collector electrode of described the 4th triode;
The base stage of described the 3rd triode connects first signal input end, and collector electrode connects described the 8th resistance, grounded emitter;
The base stage of described the 4th triode connects second signal input end, and collector electrode connects described the 8th resistance, grounded emitter.
7. video amplifier circuit according to claim 6 is characterized in that,
Described control branch road also comprises: the tenth resistance and the 11 resistance,
One end of described the tenth resistance connects described first signal input end, and the other end connects the base stage of described the 3rd triode;
One end of described the 11 resistance connects described second signal input end, and the other end connects the base stage of described the 4th triode.
8. video amplifier circuit according to claim 7 is characterized in that,
Also comprise: second electric capacity that is connected described video signal input terminal.
9. according to claim 7 or 8 described video amplifier circuits, it is characterized in that,
Also comprise: the 3rd electric capacity and the piezo-resistance that are connected described VT.
10. video amplifier circuit according to claim 9 is characterized in that,
The control signal of described first signal input end and the input of described second signal input end is same general input/output signal, perhaps is different general input/output signals.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010201371504U CN201601737U (en) | 2010-03-22 | 2010-03-22 | Video amplifying circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010201371504U CN201601737U (en) | 2010-03-22 | 2010-03-22 | Video amplifying circuit |
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| Publication Number | Publication Date |
|---|---|
| CN201601737U true CN201601737U (en) | 2010-10-06 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN2010201371504U Expired - Fee Related CN201601737U (en) | 2010-03-22 | 2010-03-22 | Video amplifying circuit |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105163003A (en) * | 2015-07-21 | 2015-12-16 | 无锡思泰迪半导体有限公司 | Integrated filter module equipped with video signal pre-amplifying circuit |
| CN108200311A (en) * | 2018-01-31 | 2018-06-22 | 商洛学院 | Monitoring image transmits signal amplifier |
-
2010
- 2010-03-22 CN CN2010201371504U patent/CN201601737U/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105163003A (en) * | 2015-07-21 | 2015-12-16 | 无锡思泰迪半导体有限公司 | Integrated filter module equipped with video signal pre-amplifying circuit |
| CN105163003B (en) * | 2015-07-21 | 2018-08-31 | 无锡思泰迪半导体有限公司 | A kind of integrated filter module containing vision signal pre-amplification circuit |
| CN108200311A (en) * | 2018-01-31 | 2018-06-22 | 商洛学院 | Monitoring image transmits signal amplifier |
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| C14 | Grant of patent or utility model | ||
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| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20101006 Termination date: 20130322 |