CN204145720U - A kind of noise canceller circuit of audio devices - Google Patents
A kind of noise canceller circuit of audio devices Download PDFInfo
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- CN204145720U CN204145720U CN201420407010.2U CN201420407010U CN204145720U CN 204145720 U CN204145720 U CN 204145720U CN 201420407010 U CN201420407010 U CN 201420407010U CN 204145720 U CN204145720 U CN 204145720U
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Abstract
The utility model discloses a kind of noise canceller circuit of audio devices, this noise canceller circuit of the present utility model comprises: observation circuit and control circuit; Observation circuit, the voltage of the Switching Power Supply of monitoring audio devices, the trigger control circuit when the initiation value that the voltage drop monitoring Switching Power Supply makes power down protection start-up point reach default; Control circuit, controls the power amplifier unit work of audio devices before being triggered, and the power amplifier unit controlling audio devices when being triggered quits work.This noise canceller circuit of the present utility model can effectively thorough stress release treatment; the supply power voltage not relying on audio devices master controller judges, can ensure the damage that quick closedown power amplifier unit causes to protect power amplifier unit to exempt from noise under the unexpected power-down conditions of audio devices.
Description
Technical field
The utility model relates to audio devices technical field, particularly a kind of noise canceller circuit of audio devices.
Background technology
At present, most Sound Bar sound system all have employed the supply power mode of external adapter single supply, solves the problem of safety certification and system interference so to greatest extent; But also bring new problem, the stress release treatment more complicated when treatment system power down, this is mainly because existing noise control circuit, the control of noise all depends on the process of master controller, but under the unexpected power-down conditions of system, system voltage also falls at the fast speed, causes master controller operating state unknowable, thus it is not thorough to cause the uncontrollable or noise of the noise of system to be eliminated.Such system can produce very large impact noise, and serious meeting directly burns out power amplifier and horn system.
Utility model content
The utility model provides a kind of noise canceller circuit of audio devices, with under the unexpected power-down conditions of resolution system, and the problem that noise causes audio frequency power amplifier to damage.
For achieving the above object, the technical solution of the utility model is achieved in that
According to an aspect of the present utility model, provide a kind of noise canceller circuit of audio devices, this circuit comprises: observation circuit and control circuit; Observation circuit is connected with the Switching Power Supply of control circuit and audio devices respectively, and control circuit is connected with the power amplifier unit of audio devices;
Observation circuit, the voltage of the Switching Power Supply of monitoring audio devices, the trigger control circuit when the initiation value that the voltage drop monitoring Switching Power Supply makes power down protection start-up point reach default;
Control circuit, controls the power amplifier unit work of audio devices before being triggered, and the power amplifier unit controlling audio devices when being triggered quits work.
Wherein, observation circuit comprises: the first clamp diode D1, the first resistance R1 and the second resistance R2;
Control circuit comprises: pull-up resistor R3, discharge resistance R4, the first triode Q1, the second triode Q2, the second clamp diode D2 and the buffer resistance R5 that powers on;
The Switching Power Supply of audio devices is connected to one end of the first resistance R1 through the first clamp diode D1, the other end of the first resistance R1 connects the second resistance R2 to ground;
The Switching Power Supply of audio devices is connected to the collector electrode of the first triode Q1 and the base stage of the second triode Q2 respectively through pull-up resistor R3, the base stage of the first triode Q1 is connected to the tie point of the first resistance R1 and the second resistance R2, the grounded emitter of the first triode Q1;
The grounded emitter of described second triode Q2;
The collector electrode of the second triode Q2 is connected to the negative electrode of the second clamp diode D2 through discharge resistance R4;
The one end of buffer resistance R5 that powers on is connected with the Switching Power Supply PVCC of audio devices, and the other end is connected with the job control point of audio devices power amplifier unit and the negative electrode of the second clamp diode D2 respectively, the plus earth of the second clamp diode D2.
Wherein, the tie point of the first resistance R1 and the second resistance R2 is chosen as power down protection start-up point.
Wherein, this circuit also comprises: the first filter capacitor C1 and charging capacitor C2;
First filter capacitor C1 is parallel to the two ends of the second resistance R2;
Charging capacitor C2 is parallel to the two ends of the second clamp diode D2.
Wherein, the first triode Q1 and the second triode Q2 is NPN type triode.
Wherein, the selection of the first resistance R1 and the second resistance R2 and the first triode Q1 meets following formula:
β＝(PVCC-α-V
D1)*R2/(R1+R2)；
Wherein, β is the conducting voltage of the first triode Q1, and PVCC is the operating voltage of audio devices Switching Power Supply, and α is the undulating value of the operating voltage of audio devices Switching Power Supply, V
d1it is the tube voltage drop of the first clamp diode D1.
Wherein, the job control point of audio devices power amplifier unit is the quiet interface of power amplifier unit.
According to another aspect of the present utility model, provide a kind of audio devices, this audio devices comprises the noise canceller circuit as the utility model aspect provides.
According to another aspect of the present utility model, provide a kind of audio devices, audio devices comprises the noise canceller circuit of the utility model aspect; Noise canceller circuit is arranged between the front stage circuits of audio devices and late-class circuit, and the late-class circuit of audio devices is also connected with horn system, and wherein, the late-class circuit of audio devices comprises power amplifier unit.
This noise canceller circuit of the present utility model is by the change in voltage of monitoring audio devices Switching Power Supply; when audio devices meets with accident power-off; turn off the process of late-class circuit power amplifier unit in advance, the noise of circuit can well be eliminated, the power amplification system of protection rear class.
Accompanying drawing explanation
Fig. 1 is the block diagram of the noise canceller circuit of a kind of audio devices that the utility model embodiment provides;
Fig. 2 is the annexation schematic diagram of the noise canceller circuit of a kind of audio devices that the utility model embodiment provides;
Fig. 3 is the schematic diagram of the switch power supply drops that the utility model embodiment provides;
Fig. 4 is the circuit diagram of the noise canceller circuit of a kind of audio devices that the utility model embodiment provides.
Embodiment
For making the purpose of this utility model, technical scheme and advantage clearly, below in conjunction with accompanying drawing, the utility model execution mode is described in further detail.
The utility model is for audio system (as the Sound bar system) noise canceller circuit under unexpected powering-off state of single power supply mode conventional at present, accident power-off refers to the unexpected power down of system that abnormal shutdown etc. causes, suddenly have a power failure in such as user family, tripping operation, or adaptor power supplies is directly pulled out.Now, the main operating voltage of system declines fast, causes master controller operating state unknowable, thus causes the noise of system cannot by main controller controls or thorough stress release treatment.
Core concept of the present utility model is when audio devices accident power-off, between the working power and late-class circuit (power amplifier unit) of audio devices, arrange noise canceller circuit, this noise canceller circuit specifically comprises: observation circuit and control circuit two parts.Concrete, observation circuit is set, and based on power amplifier (Power Amplifier, PA) operating voltage range, full load and underloaded change in voltage, obtain the safe operating voltage range of system, and calculate one and reasonably start working point, carry out ripple to the voltage of this startup working point to eliminate to solve false triggering simultaneously, when monitoring circuit monitors has reached start-up point to main supply power voltage, start the operating state controlling late-class circuit power amplifier PA, arrange rational clamp diode according to the operating voltage range at power amplifier PA control point to be broken to prevent start-up point, turn off the circuit of rear class PA system when control circuit receives control command in time thus reach the generation of quick stress release treatment, protecting rear class power amplifier PA and horn system.
Fig. 1 is the block diagram of the noise canceller circuit of a kind of audio devices that the utility model embodiment provides, and see Fig. 1, the noise canceller circuit 100 of this audio devices of the present utility model comprises: observation circuit 101 and control circuit 102; Observation circuit 101 is connected with the Switching Power Supply of control circuit 102 and audio devices respectively, and control circuit 102 is connected with the power amplifier unit of audio devices;
Observation circuit 101, the voltage of the Switching Power Supply of monitoring audio devices, the trigger control circuit when the initiation value that the voltage drop monitoring Switching Power Supply makes power down protection start-up point reach default;
Control circuit 102, controls the power amplifier unit work of audio devices before being triggered, and the power amplifier unit controlling audio devices when being triggered quits work.
In the present embodiment; this noise canceller circuit 100 first chooses power down protection start-up point in circuit; and at the voltage of this power down protection start-up point monitoring switch power supply; when the decline of Switching Power Supply makes the power down protection start-up point chosen reach default initiation value, trigger control circuit 102 controls the power amplifier unit that audio devices quits work to protect audio devices.Wherein, the voltage of power down protection start-up point is relevant to the voltage of Switching Power Supply, but is not equal to the voltage of Switching Power Supply.
Fig. 2 is the annexation schematic diagram of the noise canceller circuit of a kind of audio devices that the utility model embodiment provides; See Fig. 2, this noise canceller circuit of the present utility model is arranged between audio devices front stage circuits and late-class circuit, late-class circuit is also connected with horn system, like this when system meets with accident power-off, turn off by controlling late-class circuit, the noise produced to prevent front stage circuits enters the damage that late-class circuit causes power amplifier and horn system.Wherein, the front stage circuits of audio devices can be carry out to the received signal processing and be converted to the physical circuit of audio signal, and late-class circuit comprises the power amplifier unit of audio devices.
Fig. 3 is the schematic diagram that the utility model embodiment provides switch power supply drops; The application scenarios of composition graphs 3 pairs of the utility model noise canceller circuits is described, and see Fig. 3, ordinate axle illustrates the main working power voltage PVCC of system, and axis of abscissas represents the time.When this coordinate system represents system power supply accident power-off, the relation between power down protection start-up point and PVCC operating voltage undulating value, along with the change of time, PVCC declines.In PVCC voltage drop process, the decline of the supply voltage switch value caused due to the change of late-class circuit load on the one hand, the normal fluctuation range (representing with α) of this part and PVCC operating voltage.On the other hand, along with PVCC decline further (beyond the scope of the voltage drop of normal work, the voltage drop that unexpected power down causes can be judged as) reach crosspoint time, crosspoint represents the minimum value that rear class power amplifier normally works.Control circuit in this noise canceller circuit that the utility model provides starts switch operating state, and power amplifier unit is quit work, to protect power amplifier unit not by the damage that noise jamming causes.
Circuit structure below in conjunction with observation circuit and control circuit is specifically described this noise canceller circuit of the present utility model.Fig. 4 is the circuit diagram of the audio devices noise canceller circuit that the utility model embodiment provides; See Fig. 4,
Observation circuit 101 comprises: the first clamp diode D1, the first resistance R1 and the second resistance R2; Control circuit 102 comprises: pull-up resistor R3, discharge resistance R4, the first triode Q1, the second triode Q2, the second clamp diode D2 and the buffer resistance R5 that powers on;
The Switching Power Supply PVCC of audio devices is connected to one end of the first resistance R1 through the first clamp diode D1, the other end of the first resistance R1 connects the second resistance R2 to ground;
The Switching Power Supply PVCC of audio devices is connected to the collector electrode of the first triode Q1 and the base stage of the second triode Q2 respectively through pull-up resistor R3, the base stage of the first triode Q1 is connected to the tie point of the first resistance R1 and the second resistance R2, the grounded emitter of the first triode Q1; The grounded emitter of the second triode Q2;
The collector electrode of the second triode Q2 is connected to the negative electrode of the second clamp diode D2 through discharge resistance R4;
The one end of buffer resistance R5 that powers on is connected with the Switching Power Supply PVCC of audio devices, and the other end is connected with the job control point of audio devices power amplifier unit and the negative electrode of the second clamp diode D2 respectively, the plus earth of the second clamp diode D2.
See Fig. 4, this noise canceller circuit also comprises: the first filter capacitor C1 and charging capacitor C2;
First filter capacitor C1 is parallel to the two ends of the second resistance R2.
Charging capacitor C2 is parallel to the two ends of the second clamp diode D2.
Wherein, the first triode Q1 and the second triode Q2 is NPN type triode.
It should be noted that, in the present embodiment, triode Q1 and Q2 is NPN type triode, in other embodiments of the present utility model, also can adopt the triode of other types, be not limited to the NPN type triode in the present embodiment, concrete circuit structure also has corresponding change.
The selection of the first resistance R1 and the second resistance R2 and the first triode Q1 meets following formula:
β＝(PVCC-α-V
D1)*R2/(R1+R2)；
Wherein, β is the conducting voltage of the first triode Q1, and PVCC is the operating voltage of audio devices Switching Power Supply, and α is the undulating value of audio devices Switching Power Supply operating voltage, V
d1it is the tube voltage drop of the first clamp diode D1.
See Fig. 4, the specific works process of this noise canceller circuit of the present utility model is as follows: for ease of illustrating, the monitoring point in observation circuit is set to B point; First resistance R1 and the second resistance R2 tie point are set to A point, and A point is the power down protection start-up point of trigger control circuit operating state conversion; The job control point of power amplifier unit is set to C point.
See Fig. 4, during system worked well, the voltage of voltage transitions needed for Switching Power Supply that outside inputs by power supply adaptor, is powered to system by Switching Power Supply.The undulating value α of the Switching Power Supply operating voltage at monitoring point B point place, according to the operating characteristic of Switching Power Supply, α gets the value being more than or equal to 2V usually.During due to system works; the change of late-class circuit load also can cause the fluctuation of supply voltage switch value; this situation belongs to the normal fluctuation of Switching Power Supply work; when arranging power down protection start-up point; this factor that the magnitude of voltage that Switching Power Supply normal fluctuation causes should be declined forecloses, otherwise, when will cause system worked well; noise canceller circuit reaches power down protection start-up point and and then controls rear class power amplifier unit and quit work, to the experience that user makes troubles.
See Fig. 4, if C point place, the control working point voltage range that power down protection start-up point (A point place) voltage range is β, PA power amplifier unit is γ.
Unexpected power down is met with in Sound Bar system, system main supply power voltage PVCC is that slow decline state is until drop to 0V, according to the safe operating voltage range of this State determined system from (PVCC-α) to PVCC magnitude of voltage, namely get rid of the voltage drop caused by load normal fluctuation.Therefore, when selecting the first resistance R1, the second resistance R2 and triode Q1 being applicable to circuit, the following formula of demand fulfillment between this three:
The voltage β=(PVCC-α-V at A point place, power down protection start-up point
d1) * R2/ (R1+R2).
Wherein, PVCC is the operating voltage of system, and α is the undulating value of the operating voltage of system switching power supply, V
d1the tube voltage drop of the first clamp diode D1, V
d1occurrence relevant with the model of the diode of employing.
During system worked well, the voltage β of A point is more than or equal to 0.6V, Q1 conducting, and the current collection very low level of Q1, the base stage causing Q2 is low level, and then causes Q2 to end.Q2 ends, and the voltage of PA job control point C point is high level, and power amplifier unit PA normally works.
Along with the further decline of PVCC; reach the default starting resistor value (being less than 0.6V) of power down protection start-up point A point; the state of control circuit starts to switch; first triode Q1 transfers cut-off state to by conducting state; Q1 ends; the base stage of the second triode Q2 is caused to become high level; Q2 conducting; the collector electrode of Q2 becomes low level; at this moment the voltage γ moment of the job control working point C point (i.e. the quiet interface of power amplifier unit) of PA power amplifier unit is dragged down, and PA power amplifier unit also quits work.
Now; system front stage circuits is because unexpected power down can produce impact noise; but because PA stopped work, send at the trumpet end of audio devices so this noise can not enter into late-class circuit, thus effectively protect PA power amplifier unit horn system.
See Fig. 4, in this noise canceller circuit of the present utility model, also comprise the first filter capacitor C1 and charging capacitor C2; First filter capacitor C1 is used for carrying out ripple elimination, to solve false triggering to power down protection start-up point A point; Charging capacitor C2 is used for energy storage pressure stabilizing.
To sum up; this noise canceller circuit of the present utility model; by the judgement to system switching supply voltage; the change not relying on system master controller operating voltage carries out advanced processing to rear class PA system/power amplification system and horn system; reach the object that noise is eliminated; avoid interference and destruction that noise causes power amplification system and horn system, thus protect power amplifier unit and the horn system of audio devices.
According to another aspect of the present utility model, provide a kind of audio devices, this audio devices comprises the noise canceller circuit as described in the utility model aspect.This audio devices, owing to being integrated with aforesaid noise canceller circuit, thus well protects power amplifier unit, extends service time, provides cost savings.
The foregoing is only preferred embodiment of the present utility model, be not intended to limit protection range of the present utility model.All do within spirit of the present utility model and principle any amendment, equivalent replacement, improvement etc., be all included in protection range of the present utility model.
Claims (9)
1. a noise canceller circuit for audio devices, is characterized in that, described noise canceller circuit comprises: observation circuit and control circuit;
Observation circuit is connected with the Switching Power Supply of described control circuit and described audio devices respectively, and control circuit is connected with the power amplifier unit of described audio devices;
Observation circuit, monitors the voltage of the Switching Power Supply of described audio devices, the trigger control circuit when the initiation value that the voltage drop monitoring described Switching Power Supply makes power down protection start-up point reach default;
Control circuit, before being triggered, control the power amplifier unit work of described audio devices, the power amplifier unit controlling described audio devices when being triggered quits work.
2. noise canceller circuit according to claim 1, is characterized in that,
Described observation circuit comprises: the first clamp diode D1, the first resistance R1 and the second resistance R2;
Described control circuit comprises: pull-up resistor R3, discharge resistance R4, the first triode Q1, the second triode Q2, the second clamp diode D2 and the buffer resistance R5 that powers on;
The Switching Power Supply of described audio devices is connected to one end of described first resistance R1 through described first clamp diode D1, the described second resistance R2 of other end series connection of described first resistance R1 is to ground;
The Switching Power Supply of described audio devices is connected to the collector electrode of described first triode Q1 and the base stage of described second triode Q2 respectively through described pull-up resistor R3;
The base stage of described first triode Q1 is connected to the tie point of described first resistance R1 and described second resistance R2, the grounded emitter of described first triode Q1;
The grounded emitter of described second triode Q2;
The collector electrode of described second triode Q2 is connected to the negative electrode of the second clamp diode D2 through described discharge resistance R4;
One end of the described buffer resistance R5 that powers on is connected with the Switching Power Supply PVCC of described audio devices, the other end is connected with the job control point of described audio devices power amplifier unit and the negative electrode of described second clamp diode D2 respectively, the plus earth of described second clamp diode D2.
3. noise canceller circuit according to claim 2, is characterized in that, chooses the tie point of described first resistance R1 and described second resistance R2 as described power down protection start-up point.
4. noise canceller circuit according to claim 2, is characterized in that, described noise canceller circuit also comprises: the first filter capacitor C1 and charging capacitor C2;
Described first filter capacitor C1 is parallel to the two ends of described second resistance R2;
Described charging capacitor C2 is parallel to the two ends of described second clamp diode D2.
5. noise canceller circuit according to claim 2, is characterized in that,
Described first triode Q1 and the second triode Q2 is NPN type triode.
6. noise canceller circuit according to claim 2, it is characterized in that, the selection of described first resistance R1 and the second resistance R2 and described first triode Q1 meets following formula:
β＝(PVCC-α-V
D1)*R2/(R1+R2)；
Wherein, β is the conducting voltage of described first triode Q1, and PVCC is the operating voltage of described audio devices Switching Power Supply, and α is the undulating value of the operating voltage of described audio devices Switching Power Supply, V
d1it is the tube voltage drop of the first clamp diode D1.
7. noise canceller circuit according to claim 2, is characterized in that, the job control point of described audio devices power amplifier unit is the quiet interface of described power amplifier unit.
8. an audio devices, is characterized in that, described audio devices comprises the noise canceller circuit according to any one of claim 1-7.
9. an audio devices, is characterized in that, described audio devices comprises the noise canceller circuit according to any one of claim 1-7;
Between the front stage circuits that described noise canceller circuit is arranged on described audio devices and late-class circuit, the late-class circuit of described audio devices is also connected with horn system, and wherein, the late-class circuit of described audio devices comprises power amplifier unit.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201420407010.2U CN204145720U (en) | 2014-07-22 | 2014-07-22 | A kind of noise canceller circuit of audio devices |
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| CN201420407010.2U CN204145720U (en) | 2014-07-22 | 2014-07-22 | A kind of noise canceller circuit of audio devices |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104159178A (en) * | 2014-07-22 | 2014-11-19 | 歌尔声学股份有限公司 | Noise elimination circuit and noise elimination method for audio frequency device |
| CN105263087A (en) * | 2015-11-18 | 2016-01-20 | 广东威创视讯科技股份有限公司 | Audio output circuit capable of eliminating startup and shutdown impact sound |
| CN106686492A (en) * | 2017-01-22 | 2017-05-17 | 深圳市华星光电技术有限公司 | Audio output circuit and audio device |
| CN107147971A (en) * | 2016-03-01 | 2017-09-08 | 卡讯电子股份有限公司 | Under-voltage protection radio reception monomer and its control method |
| CN107945798A (en) * | 2017-12-18 | 2018-04-20 | 唐丙振 | A kind of voice intelligent recognition touch switch and its control method |
| CN109672960A (en) * | 2018-02-01 | 2019-04-23 | 中山市悦辰电子实业有限公司 | A kind of power amplifier and its muting control circuit |
| CN112637722A (en) * | 2020-12-21 | 2021-04-09 | 成都极米科技股份有限公司 | Mute control circuit and terminal equipment |
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2014
- 2014-07-22 CN CN201420407010.2U patent/CN204145720U/en active Active
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104159178A (en) * | 2014-07-22 | 2014-11-19 | 歌尔声学股份有限公司 | Noise elimination circuit and noise elimination method for audio frequency device |
| CN104159178B (en) * | 2014-07-22 | 2017-12-19 | 歌尔股份有限公司 | The noise canceller circuit and noise cancellation method of a kind of audio devices |
| CN105263087A (en) * | 2015-11-18 | 2016-01-20 | 广东威创视讯科技股份有限公司 | Audio output circuit capable of eliminating startup and shutdown impact sound |
| CN107147971A (en) * | 2016-03-01 | 2017-09-08 | 卡讯电子股份有限公司 | Under-voltage protection radio reception monomer and its control method |
| CN106686492A (en) * | 2017-01-22 | 2017-05-17 | 深圳市华星光电技术有限公司 | Audio output circuit and audio device |
| CN106686492B (en) * | 2017-01-22 | 2019-06-25 | 深圳市华星光电技术有限公司 | A kind of audio output circuit and audio frequency apparatus |
| CN107945798A (en) * | 2017-12-18 | 2018-04-20 | 唐丙振 | A kind of voice intelligent recognition touch switch and its control method |
| CN107945798B (en) * | 2017-12-18 | 2021-06-15 | 浙江一通电气有限公司 | Intelligent voice recognition touch switch and control method thereof |
| CN109672960A (en) * | 2018-02-01 | 2019-04-23 | 中山市悦辰电子实业有限公司 | A kind of power amplifier and its muting control circuit |
| CN112637722A (en) * | 2020-12-21 | 2021-04-09 | 成都极米科技股份有限公司 | Mute control circuit and terminal equipment |
| CN112637722B (en) * | 2020-12-21 | 2021-11-09 | 成都极米科技股份有限公司 | Mute control circuit and terminal equipment |
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Address after: 261031 Dongfang Road, Weifang high tech Industrial Development Zone, Shandong, China, No. 268 Patentee after: Goertek Inc. Address before: 261031 Dongfang Road, Weifang high tech Industrial Development Zone, Shandong, China, No. 268 Patentee before: Goertek Inc. |