CN203912161U - Noise eliminating circuit - Google Patents
Noise eliminating circuit Download PDFInfo
- Publication number
- CN203912161U CN203912161U CN201420279486.2U CN201420279486U CN203912161U CN 203912161 U CN203912161 U CN 203912161U CN 201420279486 U CN201420279486 U CN 201420279486U CN 203912161 U CN203912161 U CN 203912161U
- Authority
- CN
- China
- Prior art keywords
- triode
- effect transistor
- field effect
- plosive
- resistance
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn - After Issue
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Abstract
The utility model provides a noise eliminating circuit comprising a ground cut-off loop and a cut-off control loop. The cut-off control loop comprises a triode. The collector electrode of the triode is connected with supply voltage through a third resistor and a capacitor connected in parallel. The base electrode of the triode is connected with the mute control end of an audio power amplifier through a second resistor. The emitter electrode of the triode is connected with ground. The mute control end is connected with the supply voltage through a first resistor. The ground cut-off loop comprises a field effect transistor. The source electrode of the field effect transistor is connected with the ground end of a loudspeaker. The gate electrode of the field effect transistor is connected with the collector electrode of the triode. The drain electrode of the field effect transistor is connected with ground. The noise eliminating circuit is simple in structure, easy to produce, and capable of effectively eliminating noise.
Description
Technical field
The utility model relates to integrated circuit fields, particularly a kind of plosive elimination circuit for audio frequency power amplifier output.
Background technology
Plosive refer to audio parts powering on, power-off moment and power on stable after, the noise that is similar to " puff puff " producing on earphone or loud speaker due to the transient impact of various operations.This is that user is reluctant to hear, system design engineer always tries every possible means to avoid it.
At present, a lot of audio frequency power amplifiers all adopt single power supply in order to simplify system, will produce like this direct current biasing of 1/2nd supply voltage sizes at the output of audio frequency power amplifier.Therefore,, when output adopts Single-end output, need an external capacitance C
0carry out filtering DC component, as shown in Figure 1, in order to avoid damage loud speaker or earphone.The problem of bringing is like this that audio frequency power amplifier, when entering quiet from operating state or close (SHUTDOWN) state, may produce the burr that peak value is higher, thereby passes through capacitance C
0can on loud speaker or earphone, produce plosive.
The higher burr of common this peak value is a kind of very narrow spike, and after Fourier analysis launches, spectrum component is very abundant, and the Energy distribution in frequency domain is relatively average.The frequency range of people's ear hearing generally concentrates on 20Hz～20kHz, and amplitude range is generally more than 10mV.Therefore, from user, experience angle, should reduce the harmonic component of plosive within the scope of 20Hz～20kHz as far as possible, and be suppressed at below 10mV.
Utility model content
In order to eliminate audio power amplifier circuit at the plosive of loud speaker or the generation of earphone end, the utility model provides a kind of plosive to eliminate circuit, comprise ground connection cut-off loop and cutting-off controlling loop, wherein, described cutting-off controlling loop comprises triode, the collector electrode of described triode is connected to supply power voltage by the 3rd resistance and the electric capacity of parallel connection, its base stage is connected to the quiet control end of audio frequency power amplifier by the second resistance, its grounded emitter, described quiet control end is connected to described supply power voltage by the first resistance; Described ground connection cut-off loop comprises field effect transistor, and the source electrode of described field effect transistor is connected to the earth terminal of loud speaker or earphone, and its grid is connected to the collector electrode of described triode, its grounded drain.
Preferably, the size of described first, second, third resistance is 10k Ω～100k Ω.
Preferably, the size of described electric capacity is 1nF～0.1 μ F.
Preferably, described triode is NPN type triode, and described field effect transistor is N-channel MOS pipe.
The utility model by detect the signal of the quiet control end of audio frequency power amplifier come control loudspeaker or earphone to being switched on or switched off of earth-return, thereby reach, eliminate plosive object.Plosive of the present utility model is eliminated the simple in structure of circuit, is easy to realize, and can effectively eliminates plosive.
Accompanying drawing explanation
Fig. 1 is the connection diagram that the audio frequency power amplifier of Single-end output in prior art connects loud speaker or earphone;
Fig. 2 is the connection diagram that plosive of the present utility model is eliminated circuit and audio frequency power amplifier;
Fig. 3 is the structural representation preferred embodiment that plosive of the present utility model is eliminated circuit.
Embodiment
Below in conjunction with the drawings and specific embodiments, plosive of the present utility model is eliminated to circuit and be described in further detail, but not as to restriction of the present utility model.
As shown in Figure 2, plosive of the present utility model is eliminated circuit and is connected between the earth terminal and ground of loud speaker or earphone, by detecting the signal of the quiet control end SHD of audio frequency power amplifier, come control loudspeaker or earphone loop to be over the ground switched on or switched off, thereby reach, eliminate plosive object.
Particularly, continue with reference to figure 2, plosive of the present utility model is eliminated circuit and is had 4 port a, b, c and d.Wherein, a port is connected to the earth terminal of loud speaker or earphone, and b port is connected to the quiet control end SHD of audio frequency power amplifier, c port ground connection, and d port is connected to supply power voltage V
cC.
Fig. 3 is the structural representation preferred embodiment that plosive of the present utility model is eliminated circuit.This preferred embodiment in, plosive is eliminated circuit and is comprised ground connection cut-off loop from a port to c port and the cutting-off controlling loop from d port to c port.Wherein, cutting-off controlling loop comprises triode Q
1, triode Q
1collector electrode by the 3rd in parallel resistance R
3and capacitor C
1thereby be connected to d port and be connected to supply power voltage V
cC, triode Q
1base stage by the second resistance R
2thereby be connected to the quiet control end SHD that b port is connected to audio frequency power amplifier, triode Q
1thereby emitter be connected to c port ground connection.Between b port and d port, pass through the first resistance R
1be connected.Ground connection cut-off loop comprises field effect transistor Q
2, field effect transistor Q
2thereby source electrode be connected to the earth terminal that a port is connected to loud speaker or earphone, field effect transistor Q
2grid be connected to triode Q
1collector electrode, field effect transistor Q
2thereby drain electrode be connected to c port ground connection.
The operation principle that this plosive is eliminated circuit is: when audio frequency power amplifier is opened, the signal of quiet control end SHD is low level, triode Q
1base voltage be low, Q
1cut-off, capacitor C
1to the 3rd resistance R
3start electric discharge, Q
1collector electrode rise to high level, cause field effect transistor Q
2gate source voltage V
gSfor height, Q
2open, loud speaker or earphone to earth-return conducting.When audio frequency power amplifier turn-offs, the signal of quiet control end SHD is high level, triode Q
1base voltage be high, Q
1conducting, capacitor C
1start charging, Q
1collector electrode be down to low level, cause field effect transistor Q
2gate source voltage V
gSfor low, Q
2turn-off loud speaker or earphone earth-return is disconnected.Therefore, can avoid the saltus step of audio frequency power amplifier output to produce the noise of peak value, thereby avoid plosive generation.
Alternatively, resistance R
1, R
2and R
3span between 10k Ω～100k Ω, capacitor C
1span be 1nF～0.1 μ F.
Following table is the example that plosive of the present utility model is eliminated circuit application effect.Can find out, plosive of the present utility model is eliminated circuit and can effectively the crest voltage of the plosive noise of loud speaker or the generation of earphone end be suppressed in 1mV, thereby has eliminated plosive for people's ear.
Be understandable that, although Fig. 3 only shows triode Q
1for NPN type triode, field effect transistor Q
2for N-channel MOS pipe, but when field effect transistor that the triode triode that is any other type, field effect transistor are any other type, still can reach the purpose of this utility model, realize effect of the present utility model.
Plosive of the present utility model is eliminated circuit, by detecting the quiet control end SHD signal of audio frequency power amplifier, when audio frequency power amplifier is opened, disconnect loud speaker or earphone to earth-return, when audio frequency power amplifier turn-offs, connect loud speaker or earphone to earth-return, thereby reach, eliminate plosive object.
Above embodiment is only illustrative embodiments of the present utility model, can not be for limiting the utility model, and protection range of the present utility model is defined by the claims.Those skilled in the art can make various modifications or be equal to replacement the utility model in essence of the present utility model and protection range, these modifications or be equal to replacement and also should be considered as dropping in protection range of the present utility model.
Claims (4)
1. plosive is eliminated a circuit, comprises ground connection cut-off loop and cutting-off controlling loop, wherein,
Described cutting-off controlling loop comprises triode, the collector electrode of described triode is connected to supply power voltage by the 3rd resistance and the electric capacity of parallel connection, its base stage is connected to the quiet control end of audio frequency power amplifier by the second resistance, its grounded emitter, described quiet control end is connected to described supply power voltage by the first resistance;
Described ground connection cut-off loop comprises field effect transistor, and the source electrode of described field effect transistor is connected to the earth terminal of loud speaker or earphone, and its grid is connected to the collector electrode of described triode, its grounded drain.
2. plosive according to claim 1 is eliminated circuit, it is characterized in that, the size of described first, second, third resistance is 10k Ω～100k Ω.
3. plosive according to claim 1 is eliminated circuit, it is characterized in that, the size of described electric capacity is 1nF～0.1 μ F.
4. plosive according to claim 1 is eliminated circuit, it is characterized in that, described triode is NPN type triode, and described field effect transistor is N-channel MOS pipe.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420279486.2U CN203912161U (en) | 2014-05-28 | 2014-05-28 | Noise eliminating circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420279486.2U CN203912161U (en) | 2014-05-28 | 2014-05-28 | Noise eliminating circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203912161U true CN203912161U (en) | 2014-10-29 |
Family
ID=51786402
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420279486.2U Withdrawn - After Issue CN203912161U (en) | 2014-05-28 | 2014-05-28 | Noise eliminating circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN203912161U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103974171A (en) * | 2014-05-28 | 2014-08-06 | 上海贝岭股份有限公司 | Plosive cancelling circuit |
| CN107371093A (en) * | 2017-07-27 | 2017-11-21 | 广东长虹电子有限公司 | A kind of audio amplifier circuit |
-
2014
- 2014-05-28 CN CN201420279486.2U patent/CN203912161U/en not_active Withdrawn - After Issue
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103974171A (en) * | 2014-05-28 | 2014-08-06 | 上海贝岭股份有限公司 | Plosive cancelling circuit |
| CN103974171B (en) * | 2014-05-28 | 2017-03-15 | 上海贝岭股份有限公司 | Plosive eliminates circuit |
| CN107371093A (en) * | 2017-07-27 | 2017-11-21 | 广东长虹电子有限公司 | A kind of audio amplifier circuit |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20141029 Effective date of abandoning: 20170315 |
|
| AV01 | Patent right actively abandoned |