CN201479354U - Power amplifier muting circuit - Google Patents
Power amplifier muting circuit Download PDFInfo
- Publication number
- CN201479354U CN201479354U CN2009201778823U CN200920177882U CN201479354U CN 201479354 U CN201479354 U CN 201479354U CN 2009201778823 U CN2009201778823 U CN 2009201778823U CN 200920177882 U CN200920177882 U CN 200920177882U CN 201479354 U CN201479354 U CN 201479354U
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- branch road
- power amplifier
- control
- audio frequency
- earphone
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Abstract
The utility model discloses a power amplifier muting circuit, which relates to the technical field of electronic circuits and is designed to realize more reliable and simpler muted power amplifier output. The power amplifier muting circuit comprises an audio frequency power amplifier branch circuit, a control and process branch circuit, an earphone audio processing branch circuit and a mute control branch circuit, wherein the mute control branch circuit is connected with the earphone audio processing branch circuit via at least one of the audio signal output terminals of left and right sound channels of the earphone terminals; and the mute control branch circuit is connected with the audio frequency power amplifier branch circuit via the control and process branch circuit. The utility model can be used for such audio frequency equipment as television sets, MP3s and mobile phones.
Description
Technical field
The utility model relates to the electronic circuit technology field, relates in particular to a kind of power amplifier mute circuit.
Background technology
Existing audio frequency apparatus as television set, MP3 or mobile phone etc., generally all has two kinds of audio frequency output forms: a kind of is to carry out audio frequency output by audio frequency power amplifier; Another kind is the output that realizes audio frequency by earphone.
For the audio frequency apparatus that has power amplifier output and two kinds of audio frequency way of outputs of earphone output simultaneously, when realization is outputted to earphone output by power amplifier, need handle the audio frequency power amplifier of external output audio signal in the audio frequency apparatus, make audio signal only export by earphone.Usually the design that adopts is to use the earphone terminal that has mechanical switch to realize; when earphone inserted, the mechanical switch action by terminal inside produced control signal; and then be input in the quiet network of audio frequency power amplifier, in use there is unreliable, short-life defective in regular meeting.Usually the technical scheme that also can adopt is to use and the quiet chip of the corresponding power amplifier of power amplifier; it is programmed; when earphone inserts; insert to earphone by quiet chip detection; produce control signal; and then be input in the quiet network of audio frequency power amplifier, realize the program more complicated of quiet audio frequency power amplifier, have insecure defective.
The utility model content
The utility model provides a kind of power amplifier mute circuit, with the mechanical switch that solves available technology adopting earphone terminal inside realize audio frequency power amplifier quiet unreliable, be not durable, and adopt the quiet chip of power amplifier to realize that the quiet programming of audio frequency power amplifier is complicated, insecure problem.
For solving the problems of the technologies described above, the utility model adopts following technical scheme:
A kind of power amplifier mute circuit, comprise audio frequency power amplifier branch road, control and treatment branch road, earpiece audio processing branch road, also comprise quiet control branch road, described quiet control branch road is handled branch road by at least one output in the left and right sound channels audio signal output end of earphone terminal and described earpiece audio and is linked to each other; And described quiet control branch road links to each other with described audio frequency power amplifier branch road by described control and treatment branch road.
Wherein, described quiet control branch road comprises DC power supply, first divider resistance and switch element, and described DC power supply and described first divider resistance, described switch element are connected in series successively.One end of described switch element is in parallel with the L channel of earphone terminal or right channel audio signal output, and the other end of described switch element is connected with described audio frequency power amplifier branch road by the control and treatment branch road.
Be connected with current-limiting resistance and filter network between the described switch element and first divider resistance.Described current-limiting resistance is used to protect described switching component, and described filter network is when earphone inserts, and effectively filtering exchanges the influence of audio signal to quiet control branch road, and the voltage on the maintained switch element is stable.
Described switch element adopts a NPN type triode to realize, the base stage of described triode connects described first divider resistance, grounded emitter, collector electrode is connected with another DC power supply by second divider resistance, and described collector electrode is connected with the I/O mouth of control and treatment chip in the described control and treatment branch road.Described first divider resistance is by formula: DC power supply * (earphone resistance/(earphone resistance+first divider resistance))＜0.7V obtains, and wherein, described DC power supply is and the direct-connected DC power supply of described first divider resistance; Described earphone resistance is the earphone resistance on L channel or the right channel audio signal output.
The utility model provides a kind of power amplifier mute circuit, described quiet control branch road is connected on the channel audio signal output of described earphone terminal, self character by the earphone terminal, realize quiet power amplifier output in conjunction with quiet control branch road, thereby reach quiet purpose, and send mute signal by software programming in the prior art and realize that quiet power amplifier output compares simplicity of design, dependable performance, solved design complexity in the prior art, insecure problem; On the other hand, owing to use described switch element to carry out the transmission of quiet power amplifier output signal, to compare durability better and with low cost with the transmission of carrying out mute signal by mechanical switch action in the prior art, solved prior art and realized that by mechanical switch quiet power amplifier is not durable, insecure problem.
Description of drawings
The structural representation of the power amplifier mute circuit that Fig. 1 provides for the utility model embodiment;
The circuit diagram of the power amplifier mute circuit that Fig. 2 provides for the utility model embodiment;
STA333BW pin of chip figure in the described audio frequency power amplifier branch road that Fig. 3 provides for the utility model embodiment.
Embodiment
The utility model aims to provide a kind of power amplifier mute circuit, when switching to the earphone output audio by the power amplifier output audio, realize that quiet power amplifier output is more reliable, solved mechanical action in the prior art realize power amplifier quiet unreliable, be not durable, the quiet design complicated problems of quiet power amplifier chip programming, realized simply quiet, reliably quiet to power amplifier.
In order to enable those skilled in the art to understand the utility model scheme better, and above-mentioned purpose of the present utility model, feature and advantage can be become apparent more, the present invention is elaborated below in conjunction with drawings and Examples.
As shown in Figure 1, the power amplifier mute circuit that provides of the utility model embodiment comprises:
Audio frequency power amplifier branch road 101 mainly is with behind the amplifying than small-signal of source of sound equipment input, produces enough big electric current and goes to promote the playback that loud speaker carries out sound, is used for the external output audio signal of audio frequency apparatus.
Control and treatment branch road 102, be connected with described audio frequency power amplifier branch road, include the control and treatment chip in the described control and treatment branch road, described control and treatment chip is after receiving control signal, this signal is judged: when control signal is high level, described control and treatment branch road output audio signal is given described audio frequency power amplifier branch road, described audio frequency power amplifier branch road operate as normal, externally output audio signal; When control signal was low level, described control and treatment branch road was forbidden providing audio signal to described audio frequency power amplifier branch road, described audio frequency power amplifier branch road no signal input, thus realize quiet purpose.
Earpiece audio is handled branch road 103, be connected with earphone terminal (XS1) 105, described earpiece audio is handled branch road and is comprised the left and right sound channels audio frequency processing circuit, described left and right sound channels audio frequency processing circuit is connected with 3 pins with 5 pins of described XS1 respectively, is used for audio frequency apparatus by the earphone output audio signal; 1 pin of described XS1 is connected with 5 pins, and 4 pins are connected with 3 pins, and 2 pins are put sky or ground connection.
At least one output in the left and right sound channels audio signal output end of quiet control branch road 104, one ends and described XS1 is connected, and the other end links to each other with described audio frequency power amplifier branch road by described control and treatment branch road.Wherein, described quiet control branch road 104 comprises DC power supply, divider resistance and switch element, and described DC power supply and described first divider resistance, described switch element are connected in series successively.One end of described switch element is in parallel with the L channel of XS1 or right channel audio signal output, the other end of described switch element is connected with described audio frequency power amplifier branch road 101 by control and treatment branch road 102, utilize the self character of earphone terminal 105 and arbitrary left and right sound channels audio frequency processing circuit in the earpiece audio processing branch road 103, realized control switch element.
Power amplifier mute circuit described in the utility model adopts described quiet control branch road, handle the self character of branch road and earphone terminal in conjunction with described earpiece audio, design simple circuit and realize the quiet of power amplifier output, solve the available technology adopting mechanical switch and realized unreliability and the short-life problem that quiet power amplifier is exported, on the other hand, realize quiet power amplifier output than needs designs complicated process by integrated chip, power amplifier mute circuit described in the utility model simpler, reliable.
Specifically use the power amplifier mute circuit in television set to be example with what the another embodiment of the utility model provided below, introduce described power amplifier mute circuit in detail.
Shown in Fig. 2-3, the power amplifier mute circuit that the utility model embodiment provides comprises:
The audio frequency power amplifier branch road mainly is with behind the amplifying than small-signal of source of sound equipment input, produces enough big electric current and goes to promote the playback that loud speaker carries out sound, is used for the external output audio signal of television set.
In the present embodiment, described audio frequency power amplifier branch road adopts STA333BW chip as shown in Figure 3 to realize; 27 pin to 30 pins of described STA333BW chip are connected with the I/O mouth of control and treatment chip in the control and treatment branch road respectively, in order to received audio signal.Certainly, described audio frequency power amplifier branch road also can adopt the audio frequency power amplifier chip of other models to realize, does not give unnecessary details one by one herein.
The control and treatment branch road is connected with described audio frequency power amplifier branch road.
In the present embodiment, described control and treatment chip in the described control and treatment branch road adopts the television-specific chip, described television-specific chip is receiving control signal, it is judged: when control signal is high level, described television-specific chip output audio signal is given described STA333BW chip, described STA333BW chip operate as normal, externally output audio signal; When control signal was low level, described television-specific chip was forbidden providing audio signal to described STA333BW chip, described STA333BW chip no signal input, thus realize quiet purpose.Certainly, in described control and treatment branch road, also can adopt the control and treatment chip of other classifications to realize, not give unnecessary details one by one herein.
Earpiece audio is handled branch road, be connected with XS1, described earpiece audio is handled branch road and is comprised the left and right sound channels audio frequency processing circuit, described left and right sound channels audio frequency processing circuit all is made up of the filter network that electric capacity, resistance constitute, and described left and right sound channels audio frequency processing circuit is connected with 3 pins with 5 pins of described XS1 respectively, is used for audio frequency apparatus by the earphone output audio signal; 1 pin of described earphone terminal XS1 is connected with 5 pins, and 4 pins are connected with 3 pins, and 2 pins are put sky or ground connection.
Because it is identical that described left and right sound channels audio frequency processing circuit gets operation principle, in the present embodiment, is example with described L channel audio frequency processing circuit.
In the present embodiment, described L channel audio frequency processing circuit comprises that capacitor C 2 (2.2uF) and filter network are composed in series, wherein, described filter network is composed in parallel by capacitor C 4 (100uF/16V) and earphone resistance R 2 (2.2K Ω), and existing earphone resistance is generally 2.2K Ω.By described filter network, can filter out the unheard sound of people's ear, transfer out the sound that people's ear can be heard, its range of sounds is 20-20KHZ.
Quiet control branch road, an end is connected with 1 pin of described XS1, promptly is connected with the left channel audio signal output of described XS1, and the other end links to each other with the STA333BW chip by described television-specific chip.Wherein, described quiet control branch road comprises DC power supply M, first divider resistance R3 and the switch element.Described M and described R3, described switch element are connected in series successively.One end of described switch element is in parallel with the L channel of earphone terminal or right channel audio signal output, and the other end of described switch element is connected with the STA333BW chip by the television-specific chip.
In order to simplify circuit structure, reduce cost, described switch element adopts a NPN type triode Q1, realize the open and close performance of switching component by triode by, conducting state, the base stage of described Q1 connects described R3, grounded emitter, collector electrode is connected with another DC power supply M by the second divider resistance R6, and described collector electrode is connected with the I/O mouth of television-specific chip described in the described control and treatment branch road.
In the present embodiment, M that is connected with described R3 and the M that is connected with described R6 all adopt the 3.3V DC power supply, under the situation of the M that known described R3 connects, by first divider resistance by formula: DC power supply * (earphone resistance/(earphone resistance+first divider resistance))＜0.7V draws R3.In the present embodiment, be that 3.3V and R2 are under the situation of 2.2K Ω at M, selecting R3 is 22K Ω.Certainly the resistance of R3 is selected to be not limited in this numerical value, and R3 selects according to DC power supply and earphone resistance, and the selection of DC power supply also is based on conveniently, does not just give unnecessary details one by one herein.
For fear of the misoperation of switch element, be connected with current-limiting resistance R4 and filter network between the base stage of described Q1 and the described first divider resistance R3.
In the present embodiment, be connected with current-limiting resistance R4 (1K Ω) and filter network between described Q1 and the R3.Described filter network is by resistance R 5 (22K Ω) and capacitor C 5 (10uF) formation in parallel, and promptly described filter network is the RC filter network that is composed in parallel by RC.R4 is used to protect Q1, and filter network is that effective filtering exchanges the influence of audio signal to quiet control branch road when earphone inserts, and keeps the voltage on the Q1 stable.
When XS1 does not insert earphone jack, 5 pins of XS1 are connected with 1 pin, at this moment 3.3V voltage is by R3 (22K Ω) and R2 (2.2K Ω) electric resistance partial pressure, the Q1 base stage obtains the voltage about 0.33V, and the undertension about 0.33V is so that the conducting of Q1 pipe, and Q1 needs the voltage of 0.7V could conducting.Therefore the collector electrode of Q1 is output as high level, and after the television-specific chip received high level, output audio signal was given the STA333BW chip, and this moment, STA333BW chip operate as normal had voice output; When XS1 inserts earphone jack, 5 pins and 1 pin of XS1 are separated, at this moment 1 pin of earphone is put the high 3.3V that is, be the voltage that the Q1 base stage obtains 3.3V, the voltage of 3.3V is enough to make the Q1 conducting, so the collector electrode of Q1 is output as low level, after the television-specific chip receives low level, forbid providing audio signal to the STA333BW chip, STA333BW chip no signal input this moment, thus realize quiet purpose.
In sum, power amplifier mute circuit described in the utility model adopts described quiet control branch road, handle the self character of branch road and earphone terminal in conjunction with described earpiece audio, design simple circuit and realize the quiet of power amplifier output, solve the available technology adopting mechanical switch and realized unreliability and the short-life problem that quiet power amplifier is exported, on the other hand, realize quiet power amplifier output than needs designs complicated process by integrated chip, power amplifier mute circuit described in the utility model simpler, reliable.The utility model is applicable to audio frequency apparatus, as television set, MP3, mobile phone etc.
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 (9)
1. power amplifier mute circuit, comprise audio frequency power amplifier branch road, control and treatment branch road, earpiece audio processing branch road, it is characterized in that: also comprise quiet control branch road, described quiet control branch road is handled branch road by at least one output in the left and right sound channels audio signal output end of earphone terminal and described earpiece audio and is linked to each other; Described quiet control branch road links to each other with described audio frequency power amplifier branch road by described control and treatment branch road.
2. circuit according to claim 1 is characterized in that: described quiet control branch road comprises DC power supply, first divider resistance and switch element, and described DC power supply and described first divider resistance, described switch element are connected in series successively; One end of described switch element is in parallel with the L channel of earphone terminal or right channel audio signal output, and the other end of described switch element is connected with described audio frequency power amplifier branch road by the control and treatment branch road.
3. circuit according to claim 2 is characterized in that, is connected with current-limiting resistance between the described switch element and first divider resistance.
4. circuit according to claim 2 is characterized in that, is connected with filter network between the described switch element and first divider resistance.
5. circuit according to claim 4 is characterized in that: described filter network is the filter network that is composed in parallel by RC.
6. circuit according to claim 2, it is characterized in that: described switch element is a NPN type triode, the base stage of described triode connects described first divider resistance, grounded emitter, collector electrode is connected with another DC power supply by second divider resistance, and described collector electrode is connected with the I/O mouth of control and treatment chip in the described control and treatment branch road.
7. circuit according to claim 2 is characterized in that: described first divider resistance is by formula:
DC power supply * (earphone resistance/(earphone resistance+first divider resistance))＜0.7V
Obtain, wherein, described DC power supply is and the direct-connected DC power supply of described first divider resistance; Described earphone resistance is the earphone resistance on L channel or the right channel audio signal output.
8. according to each described circuit of claim 1-3, it is characterized in that: the control and treatment chip adopts the television-specific chip in the described control and treatment branch road.
9. according to claim 1-3 or 8 each described circuit, it is characterized in that: described audio frequency power amplifier branch road adopts STA333BW type audio frequency power amplifier chip, and 27 pin to 30 pins of described STA333BW type audio frequency power amplifier chip are connected with the I/O mouth of control and treatment chip in the described control and treatment branch road respectively.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009201778823U CN201479354U (en) | 2009-09-18 | 2009-09-18 | Power amplifier muting circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009201778823U CN201479354U (en) | 2009-09-18 | 2009-09-18 | Power amplifier muting circuit |
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| Publication Number | Publication Date |
|---|---|
| CN201479354U true CN201479354U (en) | 2010-05-19 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2009201778823U Expired - Fee Related CN201479354U (en) | 2009-09-18 | 2009-09-18 | Power amplifier muting circuit |
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| CN (1) | CN201479354U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102354883A (en) * | 2011-06-15 | 2012-02-15 | 北京天地融科技有限公司 | Audio signal transfer device |
| CN106303813A (en) * | 2015-05-15 | 2017-01-04 | 杭州纳雄科技有限公司 | A kind of head circuit and control method thereof |
| CN109195067A (en) * | 2018-07-20 | 2019-01-11 | 广州市欧智智能科技有限公司 | A kind of muting control circuit |
-
2009
- 2009-09-18 CN CN2009201778823U patent/CN201479354U/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102354883A (en) * | 2011-06-15 | 2012-02-15 | 北京天地融科技有限公司 | Audio signal transfer device |
| CN106303813A (en) * | 2015-05-15 | 2017-01-04 | 杭州纳雄科技有限公司 | A kind of head circuit and control method thereof |
| CN106303813B (en) * | 2015-05-15 | 2021-12-10 | 杭州纳雄科技有限公司 | Earphone circuit and control method thereof |
| CN109195067A (en) * | 2018-07-20 | 2019-01-11 | 广州市欧智智能科技有限公司 | A kind of muting control circuit |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 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: 20100519 Termination date: 20120918 |