CN207531051U - POP noise canceller circuits - Google Patents
POP noise canceller circuits Download PDFInfo
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- CN207531051U CN207531051U CN201721480246.9U CN201721480246U CN207531051U CN 207531051 U CN207531051 U CN 207531051U CN 201721480246 U CN201721480246 U CN 201721480246U CN 207531051 U CN207531051 U CN 207531051U
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- capacitance
- audio
- analog switch
- connect
- noise canceller
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Abstract
The utility model POP noise canceller circuits, including host scm U1, capacitance C2, analog switch U3 and audio amplification unit；The wherein audio output pin of host scm U1 is connect with the input terminal of capacitance C2；The first two-way signaling of analog switch U3 exchanges pin and is connect with the output terminal of capacitance C2, and the second two-way signaling of analog switch U3 exchanges pin ground connection, and the control switch pin of analog switch U3 is connect with the IO output pins of external microcontroller U4；The reverse inter-input-ing ending grounding of audio amplification unit, the in-phase input end of audio amplification unit are connect with the output terminal of capacitance C2.Compared with prior art, the utility model has following advantageous effect：Before carrying out voice output and stopping mutually switching, MCU sends out control signal, and analog switch is connected, and the input of such audio-frequency amplifier is just 0, avoids POP noises.After bias voltages is waited to stablize, MCU sends out control signal, closes analog switch, does not influence the transmission of normal audio.
Description
Technical field
The utility model is related to circuit fields, specifically relate to voice output circuit, for solving the output of WT588D speech chips
The problem of POP noises occurred during switching, particularly a kind of POP noise canceller circuits.
Background technology
WT588D is a widely used speech chip.Its audio output port output voltage when voice stops is
0V can be superimposed a bias voltage in voice output as 0.5VDD.Mutual switching between 0V and bias voltage, can be in audio
An additional noise, referred to as POP noises are generated on amplifier.In WT588D applications, generally require in voice output and
Switch repeatedly between stopping, generating POP noises, influence use feeling.
Utility model content
For above-mentioned technological deficiency, the purpose of this utility model is to provide a kind of POP noises for avoiding POP noises and eliminates electricity
Road.
In order to solve the above technical problems, the utility model POP noise canceller circuits, including host scm U1, capacitance
C2, analog switch U3 and audio amplification unit；The audio output pin of wherein described host scm U1 and the capacitance C2
Input terminal connection；The output terminal that the first two-way signaling of the analog switch U3 exchanges pin and the capacitance C2 connects
Connect, the second two-way signaling of the analog switch U3 exchanges pin ground connection, the control switch pin of the analog switch U3 with it is outer
Connect the IO output pins connection of microcontroller U4；The reverse inter-input-ing ending grounding of the audio amplification unit, the audio amplification unit
In-phase input end connect with the output terminal of the capacitance C2.
Preferably, the audio amplification unit includes：Audio-frequency amplifier U2, the inverting input of the audio-frequency amplifier U2
Ground connection, the in-phase input end of the audio-frequency amplifier U2 are connect with the output terminal of the capacitance C2；Loudspeaker LS1, the loudspeaker
LS1 is connect through third capacitance C3 with the output terminal of the audio-frequency amplifier U2.
Preferably, the in-phase input end of the audio-frequency amplifier U2 passes through the variable resistance RW1's and capacitance C2
Output terminal connects.
Preferably, the one end for further including the first capacitance C1, the first capacitance C1 is connected to the sound of the host scm U1
Between the input terminal of frequency output pin and the capacitance C2, the other end ground connection of the first capacitance C1.
Preferably, resistance R1 is further included, one end of the resistance R1 is connected to the audio output pipe of the host scm U1
Between the input terminal of foot and the capacitance C2, the other end ground connection of the resistance R1.
Preferably, the model WT588D of the host scm U1.
Preferably, the capacitance C2 is 4.7 μ F.
Preferably, the model 74LVC1G66 of the analog switch U3.
Preferably, the model LM386 of the audio-frequency amplifier U2.
Preferably, the model STC89C52 of the external microcontroller U4.
Compared with prior art, the utility model has following advantageous effect：The audio output pin of host scm U1
Exports audio signal is output to after audio-frequency amplifier amplifies U2 by capacitance C2 and drives loudspeaker.The first of analog switch U3
Two-way signaling exchanges pin to the output terminal of capacitance C2, and the second two-way signaling exchanges pin ground connection, and control switch pin connects
The IO output pins of external microcontroller U4.
Before carrying out voice output and stopping mutually switching, MCU sends out control signal, and analog switch is connected, such sound
The input of audio amplifier is just 0, avoids POP noises.After bias voltages is waited to stablize, MCU sends out control signal, makes analog switch
It closes, does not influence the transmission of normal audio.
Description of the drawings
Upon reading the detailed description of non-limiting embodiments with reference to the following drawings, other spies of the utility model
Sign objects and advantages will become more apparent upon.
Fig. 1 is the utility model POP noise canceller circuit schematic diagrams.
Specific embodiment
The utility model is described in further detail below, described is the explanation to the utility model rather than limit
It is fixed.The utility model is made further instructions below in conjunction with attached drawing.
One is added to be opened by the external microcontroller U4 simulations over the ground controlled in the capacitance rear end of WT588D voice outputs
U3 is closed, in voice output and before stopping mutually switching, external microcontroller U4 control analog switches U3 conducting a period of times (about tens
Millisecond), the output short-circuit of capacitance C2 is made to avoid POP noises to ground.
As shown in Figure 1, the utility model POP noise canceller circuits, are opened including host scm U1, capacitance C2, simulation
Close U3 and audio amplification unit；The wherein audio output pin of host scm U1 is connect with the input terminal of capacitance C2；Simulation
The first two-way signaling of switch U3 exchanges pin and is connect with the output terminal of capacitance C2, the second two-way signaling of analog switch U3
Pin ground connection is exchanged, the control switch pin of analog switch U3 is connect with the IO output pins of external microcontroller U4；Audio is amplified
The reverse inter-input-ing ending grounding of unit, the in-phase input end of audio amplification unit are connect with the output terminal of capacitance C2.
Audio amplification unit includes：Audio-frequency amplifier U2, the reverse inter-input-ing ending grounding of audio-frequency amplifier U2, audio-frequency amplifier
The in-phase input end of U2 is connect with the output terminal of capacitance C2；Loudspeaker LS1, loudspeaker LS1 amplify through third capacitance C3 and audio
The output terminal connection of device U2.
The in-phase input end of audio-frequency amplifier U2 is connect by variable resistance RW1 with the output terminal of capacitance C2.
The one end for further including the first capacitance C1, the first capacitance C1 is connected to the audio output pin and blocking of host scm U1
Between the input terminal of capacitance C2, the other end ground connection of the first capacitance C1.
Resistance R1 is further included, one end of resistance R1 is connected to the audio output pin of host scm U1 with capacitance C2's
Between input terminal, the other end ground connection of resistance R1.
The model WT588D of host scm U1.Capacitance C2 is 4.7 μ F.The model of analog switch U3
74LVC1G66.The model LM386 of audio-frequency amplifier U2.The model STC89C52 of external microcontroller U4.
The utility model POP noise canceller circuits include host scm U1, capacitance C2, analog switch U3, audio and put
The devices such as big device U2.The model WT588D of host scm U1, audio output pin DAC exports audio signals, passes through blocking
Capacitance C2 drives loudspeaker after being output to audio-frequency amplifier amplification U2.The first two-way signaling of analog switch U3 exchanges pin (A ends)
To the output terminal of capacitance C2, the second two-way signaling exchanges pin (B ends) and is grounded, and control switch pin (C-terminal) connects outer order
The IO output pins of piece machine U4.
Before carrying out voice output and stopping mutually switching, MCU sends out control signal, and analog switch is connected, such sound
The input of audio amplifier is just 0, avoids POP noises.After bias voltages is waited to stablize, MCU sends out control signal, makes analog switch
It closes, does not influence the transmission of normal audio.
Specific embodiment of the utility model is described above.It is to be appreciated that the utility model not office
It is limited to above-mentioned particular implementation, those skilled in the art can make a variety of changes or change within the scope of the claims,
This has no effect on the substantive content of the utility model.In the absence of conflict, the spy in embodiments herein and embodiment
Sign can be arbitrarily combined with each other.
Claims (10)
1. a kind of POP noise canceller circuits, which is characterized in that including host scm U1, capacitance C2, analog switch U3 and sound
Frequency amplifying unit；Wherein
The audio output pin of the host scm U1 is connect with the input terminal of the capacitance C2；
The first two-way signaling of the analog switch U3 exchanges pin and is connect with the output terminal of the capacitance C2, the simulation
The second two-way signaling for switching U3 exchanges pin ground connection, and the control switch pin of the analog switch U3 is with external microcontroller U4's
IO output pins connect；
The reverse inter-input-ing ending grounding of the audio amplification unit, the in-phase input end of the audio amplification unit and blocking electricity
Hold the output terminal connection of C2.
2. POP noise canceller circuits according to claim 1, which is characterized in that the audio amplification unit includes：
Audio-frequency amplifier U2, the reverse inter-input-ing ending grounding of the audio-frequency amplifier U2, the homophase input of the audio-frequency amplifier U2
End is connect with the output terminal of the capacitance C2；
Loudspeaker LS1, the loudspeaker LS1 are connect through third capacitance C3 with the output terminal of the audio-frequency amplifier U2.
3. POP noise canceller circuits according to claim 2, which is characterized in that the audio-frequency amplifier U2's is same mutually defeated
Enter end to connect with the output terminal of the capacitance C2 by variable resistance RW1.
4. POP noise canceller circuits according to claim 1, which is characterized in that further include the first capacitance C1, described first
One end of capacitance C1 is connected between the audio output pin of the host scm U1 and the input terminal of the capacitance C2, institute
State the other end ground connection of the first capacitance C1.
5. POP noise canceller circuits according to claim 1, which is characterized in that resistance R1 is further included, the resistance R1's
One end is connected between the audio output pin of the host scm U1 and the input terminal of the capacitance C2, the resistance R1
The other end ground connection.
6. POP noise canceller circuits according to claim 1, which is characterized in that the model of the host scm U1
WT588D。
7. POP noise canceller circuits according to claim 1, which is characterized in that the capacitance C2 is 4.7 μ F.
8. POP noise canceller circuits according to claim 1, which is characterized in that the model of the analog switch U3
74LVC1G66。
9. POP noise canceller circuits according to claim 2, which is characterized in that the model of the audio-frequency amplifier U2
LM386。
10. POP noise canceller circuits according to claim 2, which is characterized in that the model of the external microcontroller U4
STC89C52。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721480246.9U CN207531051U (en) | 2017-11-08 | 2017-11-08 | POP noise canceller circuits |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721480246.9U CN207531051U (en) | 2017-11-08 | 2017-11-08 | POP noise canceller circuits |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN207531051U true CN207531051U (en) | 2018-06-22 |
Family
ID=62581769
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201721480246.9U Expired - Fee Related CN207531051U (en) | 2017-11-08 | 2017-11-08 | POP noise canceller circuits |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN207531051U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107835476A (en) * | 2017-11-08 | 2018-03-23 | 上海耀华称重***有限公司 | POP noise canceller circuits |
-
2017
- 2017-11-08 CN CN201721480246.9U patent/CN207531051U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107835476A (en) * | 2017-11-08 | 2018-03-23 | 上海耀华称重***有限公司 | POP noise canceller circuits |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20180622 Termination date: 20181108 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |