CN203435137U - Circuit for eliminating shutdown POP sound of audio power amplifier - Google Patents
Circuit for eliminating shutdown POP sound of audio power amplifier Download PDFInfo
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- CN203435137U CN203435137U CN201320577990.6U CN201320577990U CN203435137U CN 203435137 U CN203435137 U CN 203435137U CN 201320577990 U CN201320577990 U CN 201320577990U CN 203435137 U CN203435137 U CN 203435137U
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Abstract
The utility model discloses a circuit for eliminating the shutdown POP sound of an audio power amplifier. The circuit comprises a fist triode, a second triode, a first resistor, a second resistor, a third resistor and a fourth resistor. A base electrode of the fist triode is connected with a power supply through the first resistor. The base electrode of the fist triode is grounded through the second resistor. A collector electrode of the fist triode is connected with the power supply of an audio system through the third resistor. An emitter electrode of the fist triode is grounded. A base electrode of the second triode is connected with the connected ends between the collector electrode of the fist triode and the third resistor. A collector electrode of the second triode is connected with the power supply through the fourth resistor. An emitter electrode of the second triode is grounded. The connected ends between the collector electrode of the second triode and the fourth resistor are connected with SD-overline ends of a pair of audio power amplifiers. The circuit has the advantage that the shutdown POP sound of the audio power amplifier is eliminated when the audio system is powered down.
Description
Technical field
The utility model relates to a kind of circuit of eliminating audio frequency power amplifier shutdown POP sound of integrated circuit fields.
Background technology
POP(explosion) sound refer to audio parts powering on, power-off moment and power on stable after, due to the explosion sound that the transient impact of various operations produces on earphone or loud speaker, in audiorange, for people's ear, can produce the noise of a kind of " puff puff ".This is that user is reluctant to hear, system design engineer always tries every possible means to avoid it.Common this transient impact 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.Our object is exactly to reduce its harmonic component in 20Hz to 20kHz scope, for most people's ears, if the peak-to-peak value voltage of signal is less than 10mV, just can't hear.
Audio frequency power amplifier is that audio-frequency power amplifier need to meet certain sequential when application, starts sequential and is divided into power supply sequential and enables sequential.Power supply sequential refers to the sequential of various chip powers power supply in system or power-off.And enable sequential, can be regarded as the precedence that device function that system power supply determines by system master after stable enables.
For power supply sequential, due to the audio frequency output of most master chips power on and power process in less stable, desirable electrifying timing sequence is that system master chip powers on prior to audio frequency power amplifier, audio frequency power amplifier and then power supply.The desirable sequential of power-off is just in time contrary, first cuts off the power supply of audio frequency power amplifier, and then cuts off the power supply of master chip.
Refer to Fig. 1, prior art sound intermediate frequency system generally includes power supply 1, DC/DC(DC-DC) transducer or LDO(Low Dropout Regulator, low pressure difference linearity) pressurizer 2, master chip 3 and a pair of audio frequency power amplifier 4.Power supply 1, DC/DC transducer or LDO pressurizer 2 are connected successively with master chip 3, and each audio frequency power amplifier 4 is all connected with master chip 3, and each audio frequency power amplifier 4 is also connected with power supply 1.The power supply of a pair of audio frequency power amplifier 4 is taken from the power supply 1 of audio system, and after start, power supply 1 is generally transmitted electricity at first to a pair of audio frequency power amplifier 4, and the voltage VDD of power supply 1 powers to master chip 3 by DC/DC transducer or 2 step-downs of LDO pressurizer more subsequently.
So actual electrifying timing sequence is audio frequency power amplifier 4, generally before master chip 3 is stable, has powered and started.In this design, need adjustment to enable sequential and guarantee normal electrifying timing sequence.While powering on, must guarantee the shutdown pin of audio frequency power amplifier 4
end, in off state, is avoided the POP sound output in master chip power up.By the time system makes shutdown pin in running order after entering stable state.During power down, also need the shutdown pin of audio frequency power amplifier 4 to be placed in off state the POP sound output while avoiding master chip power down.Conventionally the POP sound of power up is easier to solve, and is using hardware switch directly to close in the system of main power source, and POP acoustic control system during power down is difficulty comparatively.Because this type systematic cannot be predicted audio system power down in advance, cannot before power down, use controller I/O mouth quiet or close audio frequency power amplifier, in the time of also just cannot eliminating audio system power down, the POP sound of master chip is embodied in the output of audio frequency power amplifier.
Summary of the invention
The purpose of this utility model is in order to overcome the deficiencies in the prior art, and a kind of circuit of eliminating audio frequency power amplifier shutdown POP sound is provided, and cannot eliminate the problem of audio frequency power amplifier shutdown POP sound when it can solve conventional audio systems power down.
A kind of technical scheme that realizes above-mentioned purpose is: a kind of circuit of eliminating audio frequency power amplifier shutdown POP sound, connect audio system, described audio system comprises power supply, DC/DC transducer, master chip and a pair of audio frequency power amplifier, described power supply, DC/DC transducer are connected successively with master chip, and described power supply powers to described master chip by the step-down of described DC/DC transducer; Described each audio frequency power amplifier is all connected with described master chip, and described each audio frequency power amplifier is also connected with described power supply,
The circuit of described elimination audio frequency power amplifier shutdown POP sound comprises undervoltage detection circuit, and described undervoltage detection circuit comprises the first triode, the second triode, the first resistance, the second resistance, the 3rd resistance and the 4th resistance, wherein:
The base stage of described the first triode connects described power supply by described the first resistance, the base stage of described the first triode is by described the second grounding through resistance, the collector electrode of described the first triode connects described power supply, the grounded emitter of described the first triode by described the 3rd resistance;
The base stage of described the second triode connects the collector electrode of described the first triode and the end that joins of described the 3rd resistance, and the collector electrode of described the second triode connects described power supply, the grounded emitter of described the second triode by described the 4th resistance;
The end that joins of the collector electrode of described the second triode and described the 4th resistance is the output of described undervoltage detection circuit, and the output of this undervoltage detection circuit connects respectively described a pair of audio frequency power amplifier
end;
Described the first resistance and the second resistance play dividing potential drop effect, and described the first resistance is relevant with the under-voltage protection point of described audio system with the ratio of the second resistance;
During described audio system normal operation, the output output high level of described undervoltage detection circuit, described a pair of audio frequency power amplifier normal operation;
During described audio system power down, when the lower voltage of described power supply is following to the under-voltage protection point of described audio system, the output output low level of described undervoltage detection circuit, described a pair of audio frequency power amplifier shutoff.
The circuit of above-mentioned elimination audio frequency power amplifier shutdown POP sound, wherein, described DC/DC transducer replaces with LDO pressurizer, and described power supply, LDO pressurizer are connected successively with master chip, and described power supply powers to described master chip by the step-down of described LDO pressurizer.
The circuit of above-mentioned elimination audio frequency power amplifier shutdown POP sound, wherein, described power supply is 5V.
The circuit of above-mentioned elimination audio frequency power amplifier shutdown POP sound, wherein, the span of described the first resistance, the second resistance, the 3rd resistance and the 4th resistance is between 10k Ω to 100k Ω.
The circuit of above-mentioned elimination audio frequency power amplifier shutdown POP sound; wherein; the ratio of described the first resistance and the second resistance is along with the under-voltage protection point of described audio system raises and tunes up, and the ratio of described the first resistance and the second resistance is along with the under-voltage protection point of described audio system reduces and turns down.
A kind of circuit of eliminating audio frequency power amplifier shutdown POP sound of the present utility model is by adopting undervoltage detection circuit to eliminate audio frequency power amplifier shutdown POP sound, when the lower voltage of the power supply of audio system, by the setting of electric resistance partial pressure, make corresponding triode conducting or disconnection, by the output of undervoltage detection circuit and audio frequency power amplifier
end is connected, and when the supply voltage of audio system, is down to below under-voltage protection point, first audio frequency power amplifier is closed.Thereby the POP sound of avoiding master chip when audio system power down is embodied in the output of audio frequency power amplifier, solved the excessive problem of audio frequency power amplifier shutdown POP sound, eliminate audio frequency power amplifier shutdown POP sound.
Accompanying drawing explanation
Fig. 1 is the structural representation of the audio system of prior art;
Fig. 2 is a kind of circuit diagram of eliminating the circuit of audio frequency power amplifier shutdown POP sound of the present utility model;
Fig. 3 is the structural representation that adds the audio system of a kind of circuit of eliminating audio frequency power amplifier shutdown POP sound of the present utility model;
Fig. 4 be of the present utility model one application embodiment schematic diagram.
Embodiment
Refer to Fig. 2 to Fig. 4, inventor of the present utility model is in order to understand technical scheme of the present invention better, below by embodiment particularly, and is described in detail by reference to the accompanying drawings:
Refer to Fig. 2 and Fig. 3, embodiment of the present utility model, a kind of circuit of eliminating audio frequency power amplifier shutdown POP sound, connect audio system, audio system comprises power supply 1, DC/DC transducer 2, master chip 3 and a pair of audio frequency power amplifier 4, and power supply 1, DC/DC transducer 2 and master chip 3 are connected successively, and the voltage VDD of power supply 1 powers to master chip 3 by 2 step-downs of DC/DC transducer, each audio frequency power amplifier 4 is all connected with master chip 3, and each audio frequency power amplifier 4 is also connected with power supply 1.DC/DC transducer 2 can be replaced with LDO pressurizer, and power supply 1, LDO pressurizer and master chip 3 are connected successively, and power supply 1 is powered to master chip 3 by the step-down of LDO pressurizer.
A kind of circuit of eliminating audio frequency power amplifier shutdown POP sound of the present utility model comprises undervoltage detection circuit 5, and undervoltage detection circuit 5 comprises the first triode Q1, the second triode Q2, the first resistance R 1, the second resistance R 2, the 3rd resistance R 3 and the 4th resistance R 4.The first triode Q1 and the second triode Q2 are NPN type triode.
The base stage of the first triode Q1 connects power supply 1, the voltage VCC(Volt Current Condenser of power supply 1, power supply by the first resistance R 1) to undervoltage detection circuit 5 power supplies; The base stage of the first triode Q1 is GND(Ground by the second resistance R 2 ground connection); The collector electrode of the first triode Q1 connects power supply 1 by the 3rd resistance R 3; The grounded emitter of the first triode Q1.
The base stage of the second triode Q2 connects the collector electrode of the first triode Q1 and the end that joins of the 3rd resistance R 3, and the output Q1OUT of the collector electrode of the first triode Q1 gives the base stage of the second triode Q2; The collector electrode of the second triode Q2 connects power supply 1 by the 4th resistance R 4; The grounded emitter of the second triode Q2.
The end that joins of the collector electrode of the second triode Q2 and the 4th resistance R 4 is the output of undervoltage detection circuit 5, and the output of this undervoltage detection circuit 5 connects respectively a pair of audio frequency power amplifier 4
end.
The first resistance R 1 and second resistance R 2 of undervoltage detection circuit 5 play dividing potential drop effect; the first resistance R 1 is relevant with the under-voltage protection point of described audio system with second ratio of resistance R 2; the ratio of the first resistance R 1 and the second resistance R 2 is along with the under-voltage protection point of audio system raises and tunes up, and the ratio of the first resistance R 1 and the second resistance R 2 is along with the under-voltage protection point of described audio system reduces and turns down.
The under-voltage protection point that the ratio size of the first resistance R 1 and the second resistance R 2 can arrange according to the needs of the audio system of practical application arranges.If the under-voltage protection point that audio system needs is higher, the ratio of the first resistance R 1 and the second resistance R 2 need to be heightened; If the under-voltage protection point that audio system needs is lower, the ratio of the first resistance R 1 and the second resistance R 2 need to be turned down.The span of the first resistance R 1, the second resistance R 2, the 3rd resistance R 3 and the 4th resistance R 4 can be chosen between 10k Ω to 100k Ω, can reduce the power consumption of system.
When audio system works, the branch pressure voltage of the first resistance R 1 and the second resistance R 2 makes the first triode Q1 in conducting state, the voltage of the collector electrode of the first triode Q1 is low, the output Q1OUT of the first triode Q1 is low, the second triode Q2 cut-off, the voltage of the collector electrode of the second triode Q2 is high, the output of the second triode Q2
for height, i.e. the output of undervoltage detection circuit 5 output high level is given a pair of audio frequency power amplifier 4, a pair of audio frequency power amplifier 4 normal operations.
When audio system power down; undervoltage detection circuit 5 detects the lower voltage of power supply 1; when the voltage of power supply 1 is down to the under-voltage protection point of setting; the base voltage reduction of the first triode Q1 causes the first triode Q1 cut-off; the output Q1OUT of the first triode Q1 is low; the second triode Q2 conducting, the output of the second triode Q2
for low, the output output low level of undervoltage detection circuit 5 is given a pair of audio frequency power amplifier 4, and a pair of audio frequency power amplifier 4 turn-offs.Before being cut off power supply, the master chip 3 of audio system first cut off like this power supply of audio frequency power amplifier 4, also just avoid the POP sound of master chip when audio system power down to be embodied in the output of audio frequency power amplifier, solve the excessive problem of audio frequency power amplifier shutdown POP sound, eliminated audio frequency power amplifier shutdown POP sound.
Preferably, the power supply 1 of audio system is 5V, and in the audio system of this 5V power supply, if the under-voltage protection point of audio system is 3V, when the voltage of power supply 1 drops to 3V, master chip 3 and a pair of audio frequency power amplifier 4 still can work.The first resistance R 1 is set to 82k Ω, and the second resistance R 2 is set to 20k Ω, and the 3rd resistance R 3 is set to 10k Ω, and the 4th resistance R 4 is set to 10k Ω.Like this when the voltage of power supply falls when following to 3V, the voltage of the base stage of the first triode Q1 is lower than 0.6V, the first triode Q1 cut-off, the second triode Q2 conducting, the output of the second triode Q2
for low, the output output low level of undervoltage detection circuit 5 is given a pair of audio frequency power amplifier 4, and a pair of audio frequency power amplifier 4 is in off state.When the voltage of the power supply 1 of audio system is from the slow 3V that drops to of 5V when following, the level of the output output of undervoltage detection circuit 5 is switched to low level from high level, before being cut off power supply, the master chip 3 of audio system first cut off like this power supply of audio frequency power amplifier 4, also just avoid the POP sound of master chip when audio system power down to be embodied in the output of audio frequency power amplifier, solve the excessive problem of audio frequency power amplifier shutdown POP sound, eliminated audio frequency power amplifier shutdown POP sound.
The shutdown POP sound of traditional audio system and add the experiment comparing result of shutdown POP sound of audio system of a kind of circuit of eliminating audio frequency power amplifier shutdown POP sound of the present utility model as shown in the table:
Through Experimental Comparison, traditional audio system is when power down, the peak value of the signal peak of audio frequency power amplifier shutdown POP sound is between 20mV to 30mV, added a kind of audio system of eliminating the circuit of audio frequency power amplifier shutdown POP sound of the present utility model, when power down, the peak value of the signal peak of audio frequency power amplifier shutdown POP sound is less than 1mV, and people's ear be can't hear this sound.
Refer to Fig. 4, audio system integrated circuit has added a kind of circuit of eliminating audio frequency power amplifier shutdown POP sound of the present utility model, and the shutdown pin that the output of undervoltage detection circuit connects respectively a pair of audio frequency power amplifier of audio system integrated circuit is
end, thus avoid the POP sound of master chip when audio system power down to be embodied in the output of audio frequency power amplifier, having solved the excessive problem of audio frequency power amplifier shutdown POP sound, in the embodiment of this application, the model of this audio system integrated circuit is BL6306.
A kind of circuit of eliminating audio frequency power amplifier shutdown POP sound of the present utility model is by adopting undervoltage detection circuit to eliminate audio frequency power amplifier shutdown POP sound, when the lower voltage of the power supply of audio system, by the setting of electric resistance partial pressure, make corresponding triode conducting or disconnection, by the output of undervoltage detection circuit and audio frequency power amplifier
end is connected, and when the supply voltage of audio system, is down to below under-voltage protection point, first audio frequency power amplifier is closed.Thereby the POP sound of avoiding master chip when audio system power down is embodied in the output of audio frequency power amplifier, solved the excessive problem of audio frequency power amplifier shutdown POP sound, eliminate audio frequency power amplifier shutdown POP sound.
Those of ordinary skill in the art will be appreciated that, above embodiment is only for the utility model is described, and be not used as restriction of the present utility model, as long as within the scope of connotation of the present utility model, to the variation of above embodiment, modification, all will drop within the scope of claims of the present utility model.
Claims (5)
1. a circuit of eliminating audio frequency power amplifier shutdown POP sound, connect audio system, described audio system comprises power supply, DC/DC transducer, master chip and a pair of audio frequency power amplifier, described power supply, DC/DC transducer are connected successively with master chip, and described power supply powers to described master chip by the step-down of described DC/DC transducer; Described each audio frequency power amplifier is all connected with described master chip, and described each audio frequency power amplifier is also connected with described power supply,
It is characterized in that, the circuit of described elimination audio frequency power amplifier shutdown POP sound comprises undervoltage detection circuit, and described undervoltage detection circuit comprises the first triode, the second triode, the first resistance, the second resistance, the 3rd resistance and the 4th resistance, wherein:
The base stage of described the first triode connects described power supply by described the first resistance, the base stage of described the first triode is by described the second grounding through resistance, the collector electrode of described the first triode connects described power supply, the grounded emitter of described the first triode by described the 3rd resistance;
The base stage of described the second triode connects the collector electrode of described the first triode and the end that joins of described the 3rd resistance, and the collector electrode of described the second triode connects described power supply, the grounded emitter of described the second triode by described the 4th resistance;
The end that joins of the collector electrode of described the second triode and described the 4th resistance is the output of described undervoltage detection circuit, and the output of this undervoltage detection circuit connects respectively described a pair of audio frequency power amplifier
end;
Described the first resistance and the second resistance play dividing potential drop effect, and described the first resistance is relevant with the under-voltage protection point of described audio system with the ratio of the second resistance;
During described audio system normal operation, the output output high level of described undervoltage detection circuit, described a pair of audio frequency power amplifier normal operation;
During described audio system power down, when the lower voltage of described power supply is following to the under-voltage protection point of described audio system, the output output low level of described undervoltage detection circuit, described a pair of audio frequency power amplifier shutoff.
2. the circuit of elimination audio frequency power amplifier according to claim 1 shutdown POP sound, it is characterized in that, described DC/DC transducer replaces with LDO pressurizer, and described power supply, LDO pressurizer are connected successively with master chip, and described power supply powers to described master chip by the step-down of described LDO pressurizer.
3. the circuit of elimination audio frequency power amplifier shutdown POP sound according to claim 1 and 2, is characterized in that, described power supply is 5V.
4. the circuit of elimination audio frequency power amplifier shutdown POP sound according to claim 1, is characterized in that, the span of described the first resistance, the second resistance, the 3rd resistance and the 4th resistance is between 10k Ω to 100k Ω.
5. the circuit of elimination audio frequency power amplifier according to claim 1 shutdown POP sound; it is characterized in that; the ratio of described the first resistance and the second resistance is along with the under-voltage protection point of described audio system raises and tunes up, and the ratio of described the first resistance and the second resistance is along with the under-voltage protection point of described audio system reduces and turns down.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320577990.6U CN203435137U (en) | 2013-09-18 | 2013-09-18 | Circuit for eliminating shutdown POP sound of audio power amplifier |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320577990.6U CN203435137U (en) | 2013-09-18 | 2013-09-18 | Circuit for eliminating shutdown POP sound of audio power amplifier |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203435137U true CN203435137U (en) | 2014-02-12 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201320577990.6U Withdrawn - After Issue CN203435137U (en) | 2013-09-18 | 2013-09-18 | Circuit for eliminating shutdown POP sound of audio power amplifier |
Country Status (1)
| Country | Link |
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| CN (1) | CN203435137U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103458342A (en) * | 2013-09-18 | 2013-12-18 | 上海贝岭股份有限公司 | Circuit eliminating shutdown POP sound of audio power amplifier |
| CN108092627A (en) * | 2016-11-23 | 2018-05-29 | 无锡华润矽科微电子有限公司 | D class power amplifier systems |
| CN111263268A (en) * | 2020-01-15 | 2020-06-09 | 深圳市创维群欣安防科技股份有限公司 | Loudspeaker POP sound cancelling circuit and electronic product during outage |
-
2013
- 2013-09-18 CN CN201320577990.6U patent/CN203435137U/en not_active Withdrawn - After Issue
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103458342A (en) * | 2013-09-18 | 2013-12-18 | 上海贝岭股份有限公司 | Circuit eliminating shutdown POP sound of audio power amplifier |
| CN103458342B (en) * | 2013-09-18 | 2016-08-17 | 上海贝岭股份有限公司 | A kind of circuit eliminating shutdown POP sound of audio power amplifier |
| CN108092627A (en) * | 2016-11-23 | 2018-05-29 | 无锡华润矽科微电子有限公司 | D class power amplifier systems |
| CN111263268A (en) * | 2020-01-15 | 2020-06-09 | 深圳市创维群欣安防科技股份有限公司 | Loudspeaker POP sound cancelling circuit and electronic product during outage |
| CN111263268B (en) * | 2020-01-15 | 2022-02-01 | 深圳创维数字技术有限公司 | Loudspeaker POP sound cancelling circuit and electronic product during outage |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20140212 Effective date of abandoning: 20160817 |
|
| C25 | Abandonment of patent right or utility model to avoid double patenting |