CN200966099Y - Mute circuit for set-top box - Google Patents
Mute circuit for set-top box Download PDFInfo
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- CN200966099Y CN200966099Y CNU2006201570821U CN200620157082U CN200966099Y CN 200966099 Y CN200966099 Y CN 200966099Y CN U2006201570821 U CNU2006201570821 U CN U2006201570821U CN 200620157082 U CN200620157082 U CN 200620157082U CN 200966099 Y CN200966099 Y CN 200966099Y
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Abstract
A mute circuit used for set top box comprises a first control switch circuit, a second control switch circuit and a third control switch circuit. The connection point between the first control switch circuit and the second control switch circuit is connected with the negative electrode of a first diode and the positive electrode of the first diode is connected with the third control switch circuit. The mute circuit also comprises a fourth control switch circuit. The fourth control switch circuit is connected with the connection point between the first and the second control switch circuits through a second diode; the fourth control switch circuit comprises a PNP-type triode; the base electrode of the PNP-type triode is connected with the positive electrode of a third diode and the emitter of the PNP-type triode is connected with the negative electrode of a fourth diode; the positive electrode of the fourth diode is connected with the negative electrode of the third diode and simultaneously is connected with a DC power supply; the negative and positive electrodes of the third diode are connected with each other by a resistance and the negative electrode of the fourth diode is earthed by a capacitor; the positive electrode of the third diode is earthed by another capacitor. By adopting the hardware to control the switching circuit, the utility model can realize the mute action when the set top box is turned on and off and the audio digital-analog converter (DAC) starts.
Description
Technical field
The utility model relates to a kind of mute circuit of TV receiving system audio signal, especially relates to a kind of mute circuit that is used for set-top box.
Background technology
In the set-top box circuit, mute function need satisfy the user to quiet needs, all will play quiet effect when cut bank, standby, switching on and shutting down and software startup.Generally can adopt software control audio decoder process or control audio digital to analog converter DAC to realize mute function, but be not easy to realize aspect the noise of these two kinds of methods when control switch machine and audio digital to analog converter DAC startup, cause quiet effect undesirable.When existing muting control circuit starts at user's start, shutdown or master chip internal audio frequency digital to analog converter DAC, power supply by transient state to the stable state transition period, the noise of circuit inside amplifies through amplifying circuit, when exporting TV loudspeaker or audio amplifier to, can send " bang " plosive.Noise when described open and close machine and audio digital to analog converter DAC start can directly influence user's auditory effect.
The circuit diagram of Fig. 1 is that Chinese patent 200520083425.X number discloses " muting control circuit " on July 5th, 2006.In the circuit diagram of Fig. 1, provided diode DA401, electrochemical capacitor C401, NPN type triode VT402, VT404, VT405, positive-negative-positive triode VT401, VT403, resistance R 401, R402, R403, R404, R405, R406, R407, power end 3V3, mute signal output MUTE, left and right sound channels LEFT, RIGHT.
In this circuit diagram, the base stage of NPN type triode VT405 connects the mute signal output MUTE of master chip through resistance R 402, mute signal output MUTE links to each other with DC power supply 3V3 through resistance R 401, collector electrode is told two-way and is linked to each other with the base stage of two positive-negative-positive triode VT401, VT403 through resistance R 404, R406 respectively, grounded emitter interconnects through R403 between base stage and emitter.The base stage of described two positive-negative-positive triode VT401, VT403 links to each other with DC power supply 3V3 through resistance R 405, R407 respectively, emitter is through capacitor C 401 ground connection, be connected with diode between capacitor C 401 and the DC power supply 3V3, collector electrode connects the base stage of a NPN type triode VT402, VT404 separately, the collector electrode of described two NPN type triode VT402, VT404 links to each other grounded emitter with left and right sound channels LEFT, RIGHT respectively.
The operation principle of the muting control circuit of said structure is as described below.
When the GPIO of master chip mouth output high level mute signal MUTE, the 3.3V DC power supply is controlled its conducting through the base stage that resistance R 401, R402 affact NPN type triode VT405; Because its grounded emitter, the base voltage of positive-negative-positive triode VT403 is dragged down, make its saturation conduction, the 3.3V DC power supply is controlled its saturation conduction through the base stage of diode DA401, triode VT404; Because the grounded emitter of triode VT404 drags down its collector electrode level, and then the RIGHT signal of R channel drawn be low level, promptly finished mute function.When the GPIO of master chip mouth output low level signal, triode VT405 ends, and the 3.3V DC power supply affacts on the base stage of triode VT403 through resistance R 407, and it is ended; The base stage of triode VT404 is a low level, ends, and the RIGHT signal that does not influence R channel is normally exported, and promptly removes quiet.The mute circuit of L channel is identical with the foregoing circuit principle, repeats no more here.When shutdown moment, energy-storage travelling wave tube C401 discharge, diode DA401 guarantees its current flowing direction, prolongs the ON time of triode VT401, VT403, and then prolongs the quiet time, the generation of the moment impact sound of can realizing shutting down.
Described prior art is when start, shutdown, master chip internal audio frequency digital to analog converter DAC startup, need control the work of mute circuit by the GPIO mouth output control signal of master chip, and audio amplifier circuit follows transient voltage to impact when switching on and shutting down and master chip internal audio frequency digital to analog converter DAC startup, the plosive of voice output can not be eliminated automatically by existing muting control circuit, and the user still can hear the plosive of switching on and shutting down.
The utility model content
The purpose of this utility model is to provide a kind of mute circuit that is used for set-top box, the quiet effect of audio frequency when it can be implemented in open and close machine and master chip internal audio frequency digital to analog converter DAC startup.
In order to achieve the above object, the utility model is achieved by the following technical solutions:
This mute circuit comprises first, second and third control switch circuit, and the contact between first and second control switch circuit connects the negative electrode of first diode, and the anode of this first diode connects the 3rd control switch circuit.Above-mentioned mute circuit also comprises one the 4th control switch circuit, and the 4th control switch circuit links to each other with contact between first and second control switch circuit by second diode; The 4th control switch circuit comprises a positive-negative-positive triode, its base stage is connected with the anode of the 3rd diode, emitter is connected with the negative electrode of the 4th diode, the anode of the 4th diode is connected with the negative electrode of the 3rd diode, link to each other with DC power supply simultaneously, the negative electrode of the 4th diode is by a capacity earth, the anode of the 3rd diode is by another capacity earth, the negative electrode of the 3rd diode links to each other by a resistance with anode, the negative electrode of described second diode and first, contact between the two control switch circuit connects, and anode is connected with the collector electrode of positive-negative-positive triode.
Compared with prior art, the utility model adopts the hardware controls switching circuit, the quiet effect of audio frequency when can be implemented in switching on and shutting down and master chip internal audio frequency digital to analog converter DAC startup.Avoided prior art to control mute circuit because of needs by master chip, when system did not start fully, master chip can not be controlled this mute circuit, the shortcoming that this moment, noise can not be muted.
Description of drawings
Fig. 1 is the concrete circuit connection diagram of the set-top box muting control circuit of prior art.
Fig. 2 is the concrete circuit connection diagram of mute circuit of the present utility model.
Embodiment
Below in conjunction with accompanying drawing and specific implementation method the utility model is described in further detail.
See also Fig. 2, mute circuit of the present utility model is realized the quiet effect of audio frequency by the on-off action of four triodes, it comprises first, second, third and fourth control switch circuit 1,2,3,4, contact between first and second control switch circuit 1,2 connects the negative electrode of the first diode D4, and the anode of this first diode D4 connects the 3rd control switch circuit 3.The 4th control switch circuit 4 links to each other with contact between first and second control switch circuit 1,2 by the second diode D3; The 4th control switch circuit 4 comprises a positive-negative-positive triode Q1, its base stage is connected with the anode of the 3rd diode D2 through a resistance R 2, emitter is connected with the negative electrode of the 4th diode D1, the anode of the 4th diode D1 is connected with the negative electrode of the 3rd diode D2, link to each other with DC power supply V1 simultaneously, the negative electrode of the 4th diode D1 is by capacitor C E1 ground connection, the anode of the 3rd diode D2 is by capacitor C E2 ground connection, CE2 is connected between the 3rd diode D2 and the resistance R 2, the negative electrode of the 3rd diode D2 links to each other by resistance R 1 with anode, the negative electrode of the described second diode D3 and first, two control switch circuit 1, contact between 2 connects, and anode is connected with the collector electrode of positive-negative-positive triode Q1.
Described first and second control switch circuit comprises NPN type triode Q3, Q4 respectively, the collector electrode of NPN type triode Q3 links to each other with L channel AUD_L by an electric R10, and by a resistance R 11 ground connection, base stage links to each other with the negative electrode of the second diode D3 by a resistance R 6, grounded emitter, resistance R 8 one end ground connection, the other end are connected between the second diode D3 and the resistance R 6, also can be connected between resistance R 6 and the NPN type triode Q3; The collector electrode of described NPN type triode Q4 links to each other with R channel AUD_R by a resistance R 12, and by a resistance R 13 ground connection, base stage links to each other with the negative electrode of the second diode D3 by a resistance R 7, grounded emitter, resistance R 9 one end ground connection, the other end is connected between the second diode D3 and the resistance R 7, also can be connected between resistance R 7 and the NPN type triode Q4.
Described the 3rd control switch circuit 3, comprise a NPN type triode Q2, the base stage of NPN type triode Q2 links to each other with master chip mute signal control end MUTE through a resistance R 4, its base stage is through resistance R 5 ground connection, collector electrode links to each other with DC power supply V2 by resistance R 3, and collector electrode is by capacitor C E3 ground connection, grounded emitter, collector electrode links to each other with the anode of the first diode D4 simultaneously, and the negative electrode of the first diode D4 links to each other with the contact of first and second control switch circuit.
The operation principle of the mute circuit that is used for set-top box of said structure is as described below.
When start, DC power supply V1 powers on, and electric charge also arrives the base stage of positive-negative-positive triode Q1 by the emitter of the 4th diode D1 arrival positive-negative-positive triode Q1 by resistance R 1, R2.Because electric charge need charge to capacitor C E1, CE2, CE1 need be bigger than CE2 the appearance value, the base stage of described positive-negative-positive triode Q1 is at the low threshold voltage of the incipient a period of time internal ratio emitter that powers on, positive-negative-positive triode Q1 conducting this moment, at the collector electrode high level signal of output a period of time, after the first diode D4, the second diode D3 make NPN type triode Q3, Q4 conducting, the audio signal of left and right sound channels AUD_L, AUD_R is imported equivalently, thus the explosion sound when eliminating start.After V1 voltage was stable, emitter, the base voltage difference of positive-negative-positive triode Q1 reduced, and positive-negative-positive triode Q1 ends, and realize whether quiet selection by the quiet control end MUTE end of master chip this moment.When shutdown, base voltage descends, pressure reduction appears again in emitter, the base stage of positive-negative-positive triode Q1, positive-negative-positive triode Q1 conducting, collector electrode output high level signal, make NPN type triode Q3, Q4 conducting, the audio signal of AUD_L and AUD_R is imported equivalently, the explosion sound when realizing eliminating shutdown.
The effect of first, second diode D4, D3 realization or door, the quiet control signal MUTE signal output of master chip high level during start, NPN type triode Q2 conducting, when audio digital to analog converter DAC starts, before explosion sound occurring, control MUTE signal is output as low level, and NPN type triode Q2 ends, NPN type triode Q3, Q4 conducting, the function of explosion sound is eliminated in realization.
The utility model has been realized the mute function of set-top box by adopting above-mentioned simple circuit configuration, from the angle of hardware circuit, has remedied the deficiency that the muting control circuit that adopts software control mode and prior art is realized quiet effect.
Claims (10)
1, a kind of mute circuit that is used for set-top box, it comprises first, second and third control switch circuit (1,2,3), contact between first and second control switch circuit (1,2) connects the negative electrode of first diode (D4), the anode of this first diode (D4) connects the 3rd control switch circuit (3), it is characterized in that: above-mentioned mute circuit also comprises one the 4th control switch circuit (4), and the 4th control switch circuit (4) links to each other with contact between first and second control switch circuit (1,2) by second diode (D3); The 4th control switch circuit (4) comprises a positive-negative-positive triode (Q1), its base stage is connected with the anode of the 3rd diode (D2), emitter is connected with the negative electrode of the 4th diode (D1), the anode of the 4th diode (D1) is connected with the negative electrode of the 3rd diode (D2), link to each other with DC power supply (V1) simultaneously, the negative electrode of the 4th diode (D1) is by electric capacity (CE1) ground connection, the anode of the 3rd diode (D2) is by electric capacity (CE2) ground connection, the negative electrode of the 3rd diode (D2) links to each other by resistance (R1) with anode, the negative electrode and first of described second diode (D3), two control switch circuit (1,2) contact between connects, and anode is connected with the collector electrode of positive-negative-positive triode (Q1).
2, the mute circuit that is used for set-top box according to claim 1, it is characterized in that: the base stage of described positive-negative-positive triode (Q1) links to each other through the anode of a resistance (R2) with the 3rd diode (D2), and described electric capacity (CE2) is connected between the 3rd diode (D2) and the resistance (R2).
3, the mute circuit that is used for set-top box according to claim 1, it is characterized in that: described first and second control switch circuit (1,2) comprises NPN type triode (Q3, Q4) respectively, the collector electrode of NPN type triode (Q3) is connected with L channel, its base stage is by a resistance (R8) ground connection, its grounded emitter; The collector electrode of NPN type triode (Q4) is connected with R channel, and its base stage is by a resistance (R9) ground connection, grounded emitter; The base stage of described two NPN type triodes (Q3, Q4) interconnects, and links to each other with the negative electrode of second diode (D3).
4, the mute circuit that is used for set-top box according to claim 3, it is characterized in that: the base stage of described NPN type triode (Q3) links to each other with the negative electrode of second diode (D3) by a resistance (R6), and the base stage of described NPN type triode (Q4) links to each other with the negative electrode of second diode (D3) by a resistance (R7).
5, the mute circuit that is used for set-top box according to claim 3 is characterized in that: the collector electrode of described NPN type triode (Q3) links to each other with L channel by a resistance (R10), and by a resistance (R11) ground connection; The collector electrode of described triode (Q4) links to each other with R channel by a resistance (R12), and by a resistance (R13) ground connection.
6, the mute circuit that is used for set-top box according to claim 1, it is characterized in that: described the 3rd control switch circuit, comprise a NPN type triode (Q2), its base stage links to each other with master chip mute signal output, collector electrode links to each other with DC power supply (V2), simultaneously link to each other grounded emitter with the anode of first diode (D4).
7, the mute circuit that is used for set-top box according to claim 6 is characterized in that: the base stage of NPN type triode (Q2) links to each other with master chip mute signal control end through resistance (R4).
8, the mute circuit that is used for set-top box according to claim 6 is characterized in that: link to each other by resistance (R5) between the base stage of NPN type triode (Q2) and the emitter.
9, the mute circuit that is used for set-top box according to claim 6 is characterized in that: the collector electrode of NPN type triode (Q2) links to each other with DC power supply (V2) by resistance (R3).
10, the mute circuit that is used for set-top box according to claim 6 is characterized in that: NPN type triode (Q2) collector electrode is by electric capacity (CE3) ground connection.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2006201570821U CN200966099Y (en) | 2006-10-17 | 2006-10-17 | Mute circuit for set-top box |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2006201570821U CN200966099Y (en) | 2006-10-17 | 2006-10-17 | Mute circuit for set-top box |
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| Publication Number | Publication Date |
|---|---|
| CN200966099Y true CN200966099Y (en) | 2007-10-24 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU2006201570821U Expired - Fee Related CN200966099Y (en) | 2006-10-17 | 2006-10-17 | Mute circuit for set-top box |
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| Country | Link |
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| CN (1) | CN200966099Y (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101867854A (en) * | 2010-06-08 | 2010-10-20 | 吟飞科技(江苏)有限公司 | Mute control circuit |
| CN103198855A (en) * | 2013-02-26 | 2013-07-10 | 珠海市杰理科技有限公司 | Automatic noise reduction method and apparatus for playing of audio and audio player |
| CN103209346A (en) * | 2013-03-06 | 2013-07-17 | 北京赛科世纪数码科技有限公司 | Noise control device |
| CN105196934A (en) * | 2015-10-21 | 2015-12-30 | 重庆金宏汽车电子有限公司 | Muting circuit of navigation equipment |
| CN112954546A (en) * | 2021-02-01 | 2021-06-11 | 广州朗国电子科技有限公司 | Control circuit, module and terminal equipment for removing plosive by electrifying and powering off |
-
2006
- 2006-10-17 CN CNU2006201570821U patent/CN200966099Y/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101867854A (en) * | 2010-06-08 | 2010-10-20 | 吟飞科技(江苏)有限公司 | Mute control circuit |
| CN103198855A (en) * | 2013-02-26 | 2013-07-10 | 珠海市杰理科技有限公司 | Automatic noise reduction method and apparatus for playing of audio and audio player |
| CN103209346A (en) * | 2013-03-06 | 2013-07-17 | 北京赛科世纪数码科技有限公司 | Noise control device |
| CN105196934A (en) * | 2015-10-21 | 2015-12-30 | 重庆金宏汽车电子有限公司 | Muting circuit of navigation equipment |
| CN105196934B (en) * | 2015-10-21 | 2017-09-29 | 重庆金宏汽车电子有限公司 | The mute circuit of navigation equipment |
| CN112954546A (en) * | 2021-02-01 | 2021-06-11 | 广州朗国电子科技有限公司 | Control circuit, module and terminal equipment for removing plosive by electrifying and powering off |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| EE01 | Entry into force of recordation of patent licensing contract |
Assignee: Beijing TongZhou era technology limited liability company Assignor: Shenzhen Tongzhou Electronic Co., Ltd. Contract record no.: 2010440020214 Denomination of utility model: Mute circuit for set-top box Granted publication date: 20071024 License type: Exclusive License Record date: 20101122 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20071024 Termination date: 20151017 |
|
| EXPY | Termination of patent right or utility model |