CN201042052Y - A video output circuit and TV set with above video output circuit - Google Patents
A video output circuit and TV set with above video output circuit Download PDFInfo
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- CN201042052Y CN201042052Y CNU2007200189644U CN200720018964U CN201042052Y CN 201042052 Y CN201042052 Y CN 201042052Y CN U2007200189644 U CNU2007200189644 U CN U2007200189644U CN 200720018964 U CN200720018964 U CN 200720018964U CN 201042052 Y CN201042052 Y CN 201042052Y
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Abstract
The utility model discloses a video output circuit and a TV set which is provided with the video output circuit. The circuit comprises an intermediate frequency amplifying circuit, wherein, the video output circuit comprises an emitter following circuit, and the base of the emitter following circuit receives a video signal outputted by the intermediate frequency amplifying circuit; an emitter is connected with the video output terminal of an electric appliance; and the driving capability of the video signal is increased through the emitter following circuit. The video output circuit of the utility model greatly decreases the using amount of the components but not influencing the output performance of the electric appliance, thereby effectively reducing the production cost and reducing the layout space, so that a product with the circuit has greater profit and market competitive ability.
Description
Technical field
The utility model relates to a kind of signal processing circuit, specifically, relates to a kind of improvement of video signal output circuit.
Background technology
Video output is one of basic functions of present television set, its effect is that radiofrequency signal or the vision signal that this television set is received exported to other display equipment by lead-out terminal, as other television sets etc., the signal of its output is a vision signal, just videoblankingsync.For video signal output circuit,, often use amplifier circuit to export for amplitude that improves signal output or the requirement of satisfying impedance matching.The common emitter amplifying circuit has certain voltage and current amplification, and for former circuit, utilizes its voltage amplification effect just, for back level load circuit provides enough magnitudes of voltage.As shown in Figure 1, NPN type triode V205 and positive-negative-positive triode V201 cooperate peripheral circuit to form two-stage amplification output, by disposing peripheral resistance parameter, can realize that output voltage amplitude is about 2 times of input voltage amplitude, to satisfy the power demands of back level load circuit.
Emitter follower circuit does not have amplification to voltage, and still, its high input impedance and low output impedance can improve load-carrying ability.Based on cost with set type and conveniently to consider, on the television set decoding deck, need to design use component number still less penetrate the driving force that improves vision signal with output circuit.
Summary of the invention
The utility model adopts amplifier circuit to improve driving force in order to solve existing video output circuit, its baroque problem, a kind of novel video output circuit is provided, adopt emitter follower circuit to cooperate simple peripheral components, effectively improved the driving force of vision signal, simplify the circuit composing, saved cost.
For solving the problems of the technologies described above, the utility model is achieved by the following technical solutions:
A kind of video output circuit and have the television set of described video output circuit, comprise intermediate frequency amplifier circuit, wherein, in described video output circuit, include an emitter follower circuit, its base stage receives the vision signal of intermediate frequency amplifier circuit output, the video output terminal of emitter connecting circuit equipment.
In described intermediate frequency amplifier circuit, include and put chip, a NPN type triode and a resistance pressure-dividing network in one; Put the input receiving video signals of chip in described, output connects the base stage of described NPN type triode, the collector electrode of described NPN type triode connects power supply, and emitter by grounding through resistance, connects described emitter follower circuit through resistance pressure-dividing network on the one hand on the other hand.
In described resistance pressure-dividing network, the resistance of described divider resistance is set to the vision signal amplitude that makes by this resistor voltage divider network output and equals the desired signal amplitude of external loading.
In emitter follower circuit of the present utility model, include a positive-negative-positive triode, its base stage connects the output of described intermediate frequency amplifier circuit on the one hand by coupling capacitance, connect power supply through first biasing resistor on the other hand, through the second biasing resistor ground connection, for the base stage of described positive-negative-positive triode provides forward bias voltage; Grounded collector, emitter connect power supply by a resistance on the one hand, connect the video output terminal of described electric equipment on the other hand.
Compared with prior art, advantage of the present utility model and good effect are: video output circuit of the present utility model is under the prerequisite that does not influence the electric equipment output performance, significantly reduced the usage quantity of components and parts, thereby effectively reduce production cost, saved typesetting space, made and adopt the product of this circuit can obtain the bigger profit and the market competitiveness.
Description of drawings
Below in conjunction with the drawings and specific embodiments the utility model is done explanation in further detail.
Fig. 1 is the schematic diagram of existing employing two-stage amplifying type video output circuit;
Fig. 2 is the schematic diagram of intermediate frequency amplifier circuit;
Fig. 3 is the emitter following formula video output circuit schematic diagram that the utility model proposes.
Embodiment
Below in conjunction with the drawings and specific embodiments the utility model is done explanation in further detail.
In existing TV set circuit, all include the intermediate frequency amplifier section, be responsible for the intermediate-freuqncy signal of television set is carried out processing and amplifying.Intermediate frequency amplifier section of the present utility model has adopted the integrated chip LA75503 of Sanyo to cooperate simple peripheral circuit to realize.Intermediate-freuqncy signal is handled back output VEDIO_OUT signal through putting chip LA75503 in this, and this is a videoblankingsync, and the signal amplitude Vpp=2V of chip output itself connects peripheral circuit as shown in Figure 2.
Among Fig. 2, in put chip LA75503 output the VEDIO_OUT signal connect the base stage of NPN type triode V102 on the one hand by divider resistance R130, on the other hand through divider resistance R131 ground connection; Collector electrode connection+5V the DC power supply of described NPN type triode V102, emitter are on the one hand by resistance R 132 ground connection, and the resistance pressure-dividing network of forming via resistance R 134, R135 is exported the TV_VEDIO signal after handling on the other hand.Among Fig. 2, the TV_VEDIO signal with in to put the polarity of VEDIO_OUT signal of chip LA75503 output identical, just the amplitude of TV_VEDIO signal is by resistance R 134 and the decision of R135 dividing potential drop.The amplitude of VIDEO_OUT signal is 2V, and the amplitude of TV_VEDIO signal can adjust according to the needs of back circuit.The TV_VEDIO signal after the decoding chip of television set inside of leading up to is handled, finally demonstrates image by display in the processing of circuit of back; Another road is that directly video output circuit is given in coupling, connects the video output terminal of television set by described video output circuit, and then connects outside other the display device of television set, i.e. load.
Video output circuit can use multiple circuit mode: former circuit uses the two-stage common emitter to amplify, as shown in Figure 1; And the utility model has proposed a kind of new-type circuit in order to simplify circuit structure, only needs an emitter follower just can realize that Fig. 3 has provided described penetrating with circuit theory diagrams.
Among Fig. 3, C210 is a coupling capacitance, is connected the output of intermediate frequency amplifier circuit and penetrates between the base stage with positive-negative-positive triode V201 in the circuit.5V-2 provides+the 5V bias voltage, connects the base stage of positive-negative-positive triode V201 by the first biasing resistor R212, again through the second biasing resistor R222 ground connection, for the base stage of described positive-negative-positive triode V201 provides forward bias voltage.The grounded collector of described positive-negative-positive triode V201, emitter connects power supply 5V-2 by resistance R 213 on the one hand, export the video output terminal that the VEDIO signal connects television set on the other hand, finally by penetrating the driving requirement that will reach external loading with the VEDIO signal of circuit output.In the utility model, its voltage peak-to-peak value of described VEDIO semaphore request Vpp=2V.
Can not be exaggerated owing to penetrate with the voltage of circuit own, VEDIO is identical with the TV_VEDIO signal amplitude in other words, guarantee that VEDIO signal output amplitude is 2V, and the amplitude of TV_VEDIO signal also will reach 2V.The output of putting chip LA75503 during the front has illustrated is exactly Vpp=2V, this just determined in put between the output of chip LA75503 and video and do not need through any processing and amplifying, as long as guarantee that the amplitude of TV_VEDIO signal is 2V, only do the requirement that emitter follower just can satisfy video output fully with a triode V201, therefore, the such amplifying circuit of Fig. 1 just there is no need.
If the amplitude Vo of load request VEDIO signal is not equal to 2V, then can make the amplitude of the TV_VEDIO signal of output equal Vo by the resistance that changes divider resistance R134, R135, again by the driving force that improves vision signal with circuit of penetrating shown in Figure 3, to satisfy the driving requirement of external loading.
Video output circuit of the present utility model has reduced the usage quantity of components and parts to greatest extent, has effectively simplified circuit structure, has saved typesetting space.
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. video output circuit, comprise intermediate frequency amplifier circuit, it is characterized in that: include an emitter follower circuit in described video output circuit, its base stage receives the vision signal of intermediate frequency amplifier circuit output, the video output terminal of emitter connecting circuit equipment.
2. video output circuit according to claim 1 is characterized in that: include in described intermediate frequency amplifier circuit and put chip, a NPN type triode and a resistance pressure-dividing network in one; Put the input receiving video signals of chip in described, output connects the base stage of described NPN type triode, the collector electrode of described NPN type triode connects power supply, and emitter by grounding through resistance, connects described emitter follower circuit through resistance pressure-dividing network on the one hand on the other hand.
3. video output circuit according to claim 2, it is characterized in that: in described resistance pressure-dividing network, the resistance of described divider resistance is set to the vision signal amplitude that makes by this resistor voltage divider network output and equals the desired signal amplitude of external loading.
4. according to claim 1 or 2 or 3 described video output circuits, it is characterized in that: in described emitter follower circuit, include a positive-negative-positive triode, its base stage connects the output of described intermediate frequency amplifier circuit on the one hand, connect power supply through first biasing resistor on the other hand, through the second biasing resistor ground connection; Grounded collector, emitter connect power supply by a resistance on the one hand, connect the video output terminal of described electric equipment on the other hand.
5. video output circuit according to claim 4 is characterized in that: the output of described intermediate frequency amplifier circuit connects the base stage of positive-negative-positive triode in the described emitter follower circuit by coupling capacitance.
6. television set with video output circuit, described video output circuit comprises intermediate frequency amplifier circuit, it is characterized in that: include an emitter follower circuit in the described video output circuit, its base stage receives the vision signal of intermediate frequency amplifier circuit output, and emitter connects the video output terminal of television set.
7. television set according to claim 6 is characterized in that: include in described intermediate frequency amplifier circuit and put chip, a NPN type triode and a resistance pressure-dividing network in one; Put the input receiving video signals of chip in described, output connects the base stage of described NPN type triode, the collector electrode of described NPN type triode connects power supply, and emitter by grounding through resistance, connects described emitter follower circuit through resistance pressure-dividing network on the one hand on the other hand.
8. television set according to claim 7 is characterized in that: in described resistance pressure-dividing network, the resistance of described divider resistance is set to the vision signal amplitude that makes by this resistor voltage divider network output and equals the desired signal amplitude of external loading.
9. according to claim 6 or 7 or 8 described television sets, it is characterized in that: in described emitter follower circuit, include a positive-negative-positive triode, its base stage connects the output of described intermediate frequency amplifier circuit on the one hand, connect power supply through first biasing resistor on the other hand, through the second biasing resistor ground connection; Grounded collector, emitter connect power supply by a resistance on the one hand, connect the video output terminal of described television set on the other hand.
10. television set according to claim 9 is characterized in that: the output of described intermediate frequency amplifier circuit connects the base stage of positive-negative-positive triode in the described emitter follower circuit by coupling capacitance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2007200189644U CN201042052Y (en) | 2007-02-13 | 2007-02-13 | A video output circuit and TV set with above video output circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2007200189644U CN201042052Y (en) | 2007-02-13 | 2007-02-13 | A video output circuit and TV set with above video output circuit |
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| Publication Number | Publication Date |
|---|---|
| CN201042052Y true CN201042052Y (en) | 2008-03-26 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU2007200189644U Expired - Fee Related CN201042052Y (en) | 2007-02-13 | 2007-02-13 | A video output circuit and TV set with above video output circuit |
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| Country | Link |
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| CN (1) | CN201042052Y (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106060436A (en) * | 2016-03-28 | 2016-10-26 | 乐视控股（北京）有限公司 | Video output method, video output circuit and multimedia terminal |
| CN108134382A (en) * | 2018-01-23 | 2018-06-08 | 杭州矩视科技有限公司 | The anti-overvoltage circuit and electronic equipment of a kind of analog video signal |
-
2007
- 2007-02-13 CN CNU2007200189644U patent/CN201042052Y/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106060436A (en) * | 2016-03-28 | 2016-10-26 | 乐视控股（北京）有限公司 | Video output method, video output circuit and multimedia terminal |
| CN108134382A (en) * | 2018-01-23 | 2018-06-08 | 杭州矩视科技有限公司 | The anti-overvoltage circuit and electronic equipment of a kind of analog video signal |
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| 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: 20080326 Termination date: 20110213 |