CN201001104Y - Impact sound preventing circuit - Google Patents
Impact sound preventing circuit Download PDFInfo
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- CN201001104Y CN201001104Y CNU200720118051XU CN200720118051U CN201001104Y CN 201001104 Y CN201001104 Y CN 201001104Y CN U200720118051X U CNU200720118051X U CN U200720118051XU CN 200720118051 U CN200720118051 U CN 200720118051U CN 201001104 Y CN201001104 Y CN 201001104Y
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Abstract
The utility model discloses an impulsive sound prevention circuit, which processes the impulsive sound prevention for an audio power amplifier. The utility model comprises a start-up mute circuit, a shutdown mute circuit, and a power power-up/power-down treating circuit, wherein the start-up mute circuit is connected in series between the mute control end and the power end of the audio power amplifier, and comprises a first RC network and a first transistor (Q1) connected in series, when the power is inputted, the first transistor (Q1) is turned on to make the mute control end of the audio power amplifier keep the low potential in the mute state; the shutdown mute circuit comprises a second RC network and a second transistor (Q2) connected in series, when the power is cut off, the second capacitor (C2) in the second RC network discharges, and the second transistor (Q2) is turned on to make the mute control end keep the low potential in the mute state; the power power-up/power-down treating circuit operates the slow voltage increase and the slow voltage step down of the power of the audio power amplifier. The circuit is in particular suitable for the TV and the middle and low power acoustics, thus the utility model has the advantages that the circuit structure is simple and the cost is lower.
Description
Technical field
The utility model relates to a kind of impulsive sound that is applied in TV, the middle low power sound equipment and prevents circuit.
Background technology
Impulsive sound is meant that audio parts (mainly being audio-frequency power amplifier) is powering on, cutting off the power supply moment, and power on stable after, the explosion sound that transient impact produced that various operations bring.Normally a kind of very narrow spike of this transient impact, after the Fourier analysis expansion, its spectrum component is very abundant, and the Energy distribution in frequency domain is average relatively, the purpose that solves impulsive sound is exactly the harmonic component that will reduce in 20Hz～20kHz scope, because for most people, if the impulsive sound that the crest voltage of pulse signal sends during less than 10mV has not just been heard.
What at present, solve that audio parts produces impulsive sound prevents that circuit is roughly as follows:
The one, adopt BTL bridge-type output power amplifier, it can add the earth and improve power output under identical supply voltage, also save output capacitance, identical impulsive sound can appear at positive output end ("+"), the negative output terminal ("-") of bridge-type export structure simultaneously, by the impulsive sound that can will cancel out each other and send after the loudspeaker.The BTL bridge architecture for power on, power down and gimp all have the good restraining effect; But,, cause circuit cost to increase because the BTL bridge architecture needs double port number.
Another kind of impulsive sound prevents that circuit from being the mode that adopts relay to separate, power amplifier output is electrically connected with loud speaker by relay, at start, shutdown moment control relay relay and loud speaker are disconnected, relay is connected with loud speaker.Impulsive sound prevents more thorough in this circuit; But, owing to need in circuit, increase relay, both increased the cost of circuit, also increased the volume of circuit, so circuit structure generally only is used for professional high power acoustics circuit.
Summary of the invention
The purpose of this utility model is to propose a kind of impulsive sound that especially is fit to be applied in TV, the middle low power sound equipment and prevents circuit, has simple, the lower-cost advantage of circuit structure.
For addressing the above problem, the utility model discloses a kind of impulsive sound and prevents circuit, and the processing to audio-frequency power amplifier prevents to produce impulsive sound comprises:
The turn-on muting circuit, be serially connected between the quiet control end and power end of described audio-frequency power amplifier, first RC network and the first transistor that comprise serial connection, when the input power supply was connected in start, it was the electronegative potential of mute state that the first transistor conducting makes the quiet control end of described audio-frequency power amplifier;
The shutdown mute circuit, be serially connected between the quiet control end and power end of described audio-frequency power amplifier, second RC network and the transistor seconds that comprise serial connection, when shutdown disconnects the input power supply, second capacitor discharge in second RC network, it is the electronegative potential of mute state that the transistor seconds conducting makes the quiet control end of described audio-frequency power amplifier;
Power supply electrifying/power down process circuit is connected between the input power pin end of power end and described audio-frequency power amplifier, and the power source voltage of importing described audio-frequency power amplifier is done the slow slow processing of falling that rises.
More preferably, this circuit also comprises:
The software mute circuit, be connected with the base stage of the first transistor of described turn-on muting circuit, first diode and first resistor that comprise serial connection, quiet time of described turn-on muting circuit then, control signal to the anode of first diode by I/O control interface input high level, control the first transistor conducting makes the quiet control end of described audio-frequency power amplifier be maintained the electronegative potential of mute state.
More preferably, described first RC network comprises: Chuan Jie first resistor, capacitor and the 3rd resistor successively; And an end ground connection, the other end is connected the 4th resistor of first capacitor and the 3rd resistor common port.
More preferably, described second RC network comprises the 5th, the 7th resistor and second capacitor, and wherein, the 5th resistor is connected with described power end, and the 7th resistor one end ground connection, the other end is with the negative pole of second capacitor and the emitter of transistor seconds are connected respectively;
More preferably, described turn-on muting circuit and described shutdown mute circuit all also comprise:
The 3rd RC network is serially connected between the quiet control end of the collector electrode of the first transistor and described audio-frequency power amplifier, comprises the 6th resistor and the 3rd capacitor.
More preferably, in described turn-on muting circuit and the described shutdown mute circuit, the collector electrode of the first transistor is connected with power input by the 8th resistor.
More preferably, described power supply electrifying/power down process circuit specifically comprises:
The 4th diode, its anode connects described power input, its negative electrode connects a delay loop, this delay loop comprises the tenth resistor, first metal-oxide-semiconductor field effect transistor, first inductor and the 9th resistor of serial connection successively, and this delay loop is connected with the input power pin end of described audio-frequency power amplifier;
Filter capacitor, in parallel with described the 9th resistor, one end ground connection, the other end connects the input power pin end of described audio-frequency power amplifier;
The 15 capacitor, an end ground connection, the other end is connected the 11, between the 17 voltage grading resistor, and couples with the 3rd transistorized base stage;
When connecting the input power supply, power supply charges to filter capacitor by the tenth resistor, first inductor, the voltage at its two ends slowly rises, and the 15 capacitor voltage at both ends also rises thereupon, the 3rd transistor turns, make the first metal-oxide-semiconductor field effect transistor conducting that couples with the 3rd transistor collector, the voltage at filter capacitor two ends rises to input supply voltage.
More preferably, described power supply electrifying/power down process circuit also comprises: the 5th diode, and its anode is connected with the 3rd transistorized base stage, and negative electrode is connected with an end of the 15 capacitor.
More preferably, described the tenth resistor is a thermistor.
More preferably, described first metal-oxide-semiconductor field effect transistor is PMOS, and its source electrode is connected the two ends of the tenth resistor respectively with drain electrode, and its grid is coupled to the 3rd transistorized collector electrode, makes the conducting with the 3rd transistorized conducting of described first metal-oxide-semiconductor field effect transistor.
Compared with prior art, the utlity model has following beneficial effect:
The utility model can effectively prevent the impulsive sound that audio frequency amplifier produces, and has the advantage that circuit is simple, relative cost is lower, especially is fit to be applied in TV, the middle low power sound equipment audio frequency amplifier be prevented the processing of impulsive sound.
Description of drawings
Fig. 1 is the circuit diagram of a preferred embodiment of the utility model.
Embodiment
Circuit of the present utility model is the electric pulse impulsive sound that prevents that audio-frequency power amplifier from producing in start, shutdown, power supply electrifying/power down and steady operation process.
Please participate in shown in Figure 1ly, be the circuit diagram of a preferred embodiment of the utility model.Wherein, the quiet control end of this example sound intermediate frequency power amplifier is that low level is quiet.
Circuit of the present utility model mainly comprises: turn-on muting circuit 110, shutdown mute circuit 120, power supply electrifying/power down process circuit 130, software mute circuit, all be electrically connected with audio-frequency power amplifier 140, be respectively applied for the electric pulse impulsive sound that described audio-frequency power amplifier 140 is produced and do quiet processing in power supply electrifying/power down and steady operation process, prevent that described audio-frequency power amplifier 140 from sending impulsive sound.
Wherein, described turn-on muting circuit 110 comprises: first RC network that resistor R 2, R3, R4 and capacitor C1 constitute, with the D2 of resistor R 4 parallel connections, transistor Q1 that the base stage RC network is electrically connected and be serially connected in power end 150 and the collector electrode of transistor Q1 between the 3rd RC network of quiet control end (MUTE) of resistor R 8, the collector electrode that is serially connected in transistor Q1 and described audio-frequency power amplifier 140, it is made of resistor R 6 and capacitor C3.
In addition, described software mute circuit comprises: the diode D1 that anode is connected with exterior I O control interface 160, the base stage of electrical connection transistor Q1 behind its negative electrode series resistor device R1.
During start, the power supply of power end 150 input+24V (giving an example), transistor Q1 is saturation conduction owing to base stage moment acquisition high level, and collector electrode is output as low level, and described audio-frequency power amplifier 140 is muted (serves as effective with its quiet control end input low level).Simultaneously, in first RC network, capacitor C1 is by resistor R 2, R3, R4 charging, according to the charging interval of first RC network, near in the supply voltage, high level signal of exterior I O interface 160 inputs is given diode D1 positive terminal in the both end voltage of capacitor C1, keep the lasting saturation conduction of Q1, its collector electrode is output as low level, described audio-frequency power amplifier 140 is muted, till whole system is finished power up.
Thus, above-mentioned turn-on muting circuit 110 is that powered on moment provides the quiet of a short time for described audio-frequency power amplifier 140, promptly, the quiet control end that makes described audio-frequency power amplifier 140 is low level (under the effective situation of its electronegative potential), and the time is determined by the RC parameter in the charging voltage and first RC network; Cooperate the MCU control of this circuit outside, utilize described software mute circuit to come relay, obtain the quiet of controlled long period.
Described power supply electrifying/power down process circuit 130 slowly falls processing for the power supply that offers described audio-frequency power amplifier 140 being carried out slow liter of voltage, prevents the impulsive sound that the bust that jumps of supply voltage occurs when switching on and shutting down.This circuit comprises: the diode D4 that anode is connected with described power end 150, and its negative electrode is connected to M1; The delay loop that resistor R 10, metal-oxide-semiconductor field effect transistor M1 and inductor L1, resistor R 9 and back load thereof are formed;
Wherein, metal-oxide-semiconductor field effect transistor M1 is a PMOS, and its source electrode is connected with the two ends of resistor R 10 respectively with drain electrode, and grid passes through resistor R 13 and is connected with the collector electrode of transistor Q3, and is connected resistor R 12 between source electrode and the grid; And the grounded emitter of transistor Q3, base stage connects the anode of voltage stabilizing didoe D5, is connected to the common port of voltage grading resistor R11 and R17 by voltage stabilizing didoe D5, and capacitor C15 is in parallel with voltage grading resistor R17.In addition, the two ends of resistor R 9 are parallel with filter capacitor C5 and C6.
Described resistor R 10 is a thermistor, and its characteristic is a negative temperature coefficient, and temperature is high more, and resistance is low more.When the start energized, in the delay loop of forming by thermistor R10 and inductor L1, MOS transistor M1, resistor R 9 and back load thereof, because the characteristic of this thermistor R10 is a negative temperature coefficient, temperature is high more, its resistance is low more, therefore, resistor R 9 and with resistor R 9 load in parallel (resistor R 9 can be with the load replacement of its back, not necessarily, also can play the effect of rapid discharge during power remove) dividing potential drop that go up to obtain is curved rising, selects suitable thermistor R10 can make curve mild relatively.
When the start energized, diode D4 conducting, under the divider resistance effect of forming by resistor R 11 and resistor R 17, capacitor C15 begins charging, along with the voltage of resistor R 10 with inductor L1 common port rises and quick charge, the voltage at its two ends progressively rises, and its maximum charging voltage is the component of voltage on the resistor R 17; When the both end voltage of capacitor C15 rises to a certain degree, after being the voltage stabilizing value of both end voltage of capacitor C15 greater than diode D5, transistor Q3 conducting, make the common port of resistor R 12 and resistor R 13, also promptly descend rapidly with the voltage of the grid of P type metal-oxide-semiconductor field effect transistor M1, make the rapid conducting of metal-oxide-semiconductor field effect transistor M1, cause the voltage of thermistor R10 and inductor L1 common port to rise to rapidly thus near the supply voltage of importing.
In addition, in energized moment, power supply is at first given filter capacitor C5 and C6 charging by diode D4, the tenth resistor R 10, inductor L1, the voltage at its two ends slowly rises, after metal-oxide-semiconductor field effect transistor M1 conducting, the input power supply directly is added in filter capacitor C5 and C6 two ends by diode D4, metal-oxide-semiconductor field effect transistor M1, inductor L1, makes the voltage at filter capacitor C5 and C6 two ends rise to input supply voltage.Thus, inductor L1 plays certain delayed action and anti-conducted interference effect in circuit.
At this moment, the power supply of described audio-frequency power amplifier 140 is supplied with power up and is finished, and controls described software mute circuit and stop quietly, and described audio-frequency power amplifier 140 just can operate as normal.
When power supply power-fail, since resistor R 9 parallel connections several big filter capacitor C5, C6 and C7, energy storage is bigger, during power cutoff because the existence of diode D4, these energy can't be released by the reverse general supply of diode D4 loop, can only slowly release by bleed-off circuits such as resistor R 11, R17 and R9, avoid power supply to fall suddenly and cause the shutdown impulsive sound.
Described shutdown mute circuit 120 is to shut down moment for described audio-frequency power amplifier 140 provides a lasting short time quiet, occurs sonic boom when preventing to shut down.This circuit comprises: second RC network, constitute by resistor R 5, R7 and capacitor C2, resistor R 5 is connected with described power end 150, and resistor R 7 be connected with the negative pole of capacitor C2, the emitter of transistor Q2; The base earth of this transistor Q2, collector series connection resistor R 8 backs are connected with described power end 150, and the collector electrode of transistor Q2 is by being connected the quiet control end of described audio-frequency power amplifier 140 with the 3rd RC network that capacitor C3 constitutes by resistor R 6.
Described shutdown mute circuit 120 is to shut down moment for described audio-frequency power amplifier 140 provides a lasting short time quiet, occurs sonic boom when preventing to shut down, and wherein, the quiet time is determined by second RC network (R5, C2, R7) parameter.
During power cutoff, because capacitor C2 is by resistor R 5 and diode D3 charging when work, so in case power supply disconnects, capacitor C2 can pass through the bleed-off circuit discharge of resistor R 5, R7 composition, transistor Q2 emitter voltage is dropped to below 0.7 volt, the voltage of substituting the bad for the good when still having capacitor C3 to go up work on the collector electrode, make the rapid conducting of transistor Q2, for the residual voltage on the capacitor C2 provides a quick bleed-off circuit, make described audio-frequency power amplifier 140 enter mute state, realize that shutdown is quiet.
In addition, in order to reduce impulsive sound better, in the peripheral circuit of described audio-frequency power amplifier 140, be connected and negative input power pin end (the choosing value of the partially installing capacitor C14 Vp), output coupling capacitor C9 and C11 also is some factors that influence impulsive sound, but specifically to decide, not invent the row of discussion at this according to the form of the described audio-frequency power amplifier of selecting 140.
The power amplifier 140 that adopts for example among the present invention is that input low level is quiet, and quiet but some power amplifier is a high level, it prevents the principle unanimity of impulsive sound, does not enumerate one by one at this.
To sum up, owing to adopt as above technical scheme, the utility model can effectively prevent the impulsive sound that audio frequency amplifier produces, and has the advantage that circuit is simple, relative cost is lower, especially is fit to be applied in TV, the middle low power sound equipment audio frequency amplifier be prevented the processing of impulsive sound.
Claims (10)
1, a kind of impulsive sound prevents circuit, and the processing to audio-frequency power amplifier prevents to produce impulsive sound is characterized in that, comprising:
The turn-on muting circuit, be serially connected between the quiet control end and power end of described audio-frequency power amplifier, first RC network and the first transistor (Q1) that comprise serial connection, when the input power supply was connected in start, it was the electronegative potential of mute state that the first transistor (Q1) conducting makes the quiet control end of described audio-frequency power amplifier;
The shutdown mute circuit, be serially connected between the quiet control end and power end of described audio-frequency power amplifier, second RC network and the transistor seconds (Q2) that comprise serial connection, when shutdown disconnects the input power supply, second capacitor (C2) discharge in second RC network, it is the electronegative potential of mute state that transistor seconds (Q2) conducting makes the quiet control end of described audio-frequency power amplifier;
Power supply electrifying/power down process circuit is connected between the input power pin end of power end and described audio-frequency power amplifier, and the power source voltage of importing described audio-frequency power amplifier is done the slow slow processing of falling that rises.
2, impulsive sound according to claim 1 prevents circuit, it is characterized in that, also comprises:
The software mute circuit, be connected with the base stage of the first transistor (Q1) of described turn-on muting circuit, first diode (D1) and first resistor (R1) that comprise serial connection, quiet time of described turn-on muting circuit then, control signal to the anode of first diode (D1) by I/O control interface input high level, the conducting of control the first transistor (Q1), the quiet control end that makes described audio-frequency power amplifier is the electronegative potential of mute state.
3, impulsive sound according to claim 1 prevents circuit, it is characterized in that, described first RC network comprises: Chuan Jie first resistor (R2), capacitor (C1) and the 3rd resistor (R3) successively; And an end ground connection, the other end is connected the 4th resistor (R4) of first capacitor (C1) and the 3rd resistor (R3) common port.
4, impulsive sound according to claim 1 prevents circuit, it is characterized in that, described second RC network comprises the 5th, the 7th resistor (R5 and R7) and second capacitor (C2), wherein, the 5th resistor (R5) is connected with described power end, and the 7th resistor (R7) end ground connection, the other end is with the negative pole of second capacitor (C2) and the emitter of transistor seconds (Q2) are connected respectively.
5, impulsive sound according to claim 1 prevents circuit, it is characterized in that, described turn-on muting circuit and described shutdown mute circuit all also comprise:
The 3rd RC network is serially connected between the quiet control end of the collector electrode of the first transistor (Q1) and described audio-frequency power amplifier, comprises the 6th resistor (R6) and the 3rd capacitor (C3).
6, impulsive sound according to claim 1 prevents circuit, it is characterized in that, in described turn-on muting circuit and the described shutdown mute circuit, the collector electrode of the first transistor (Q1) is connected with power input by the 8th resistor (R8).
7, impulsive sound according to claim 1 prevents circuit, it is characterized in that, described power supply electrifying/power down process circuit specifically comprises:
The 4th diode (D4), its anode connects described power input, its negative electrode connects a delay loop, this delay loop comprises the tenth resistor (R10), first metal-oxide-semiconductor field effect transistor (M1), first inductor (L1) and the 9th resistor (R9) of serial connection successively, and this delay loop is connected with the input power pin end of described audio-frequency power amplifier;
Filter capacitor (C5 and C6), in parallel with described the 9th resistor (R9), one end ground connection, the other end connects the input power pin end of described audio-frequency power amplifier;
The 15 capacitor (C15), an end ground connection, the other end be connected serial connection the 11, between the 17 voltage grading resistor (R11, R17), and couple with the base stage of the 3rd transistor (Q3);
When connecting the input power supply, power supply is given filter capacitor (C5 and C6) charging by the tenth resistor (R10), first inductor (L1), the voltage at its two ends slowly rises, and the 15 capacitor (C15) both end voltage also rises thereupon, the 3rd transistor (Q3) conducting, make first metal-oxide-semiconductor field effect transistor (M1) conducting that couples with the 3rd transistor (Q3) collector electrode, the voltage at filter capacitor (C5 and C6) two ends rises to input supply voltage.
8, impulsive sound according to claim 7 prevents circuit, it is characterized in that, described power supply electrifying/power down process circuit also comprises: the 5th diode (D5), and its anode is connected with the base stage of the 3rd transistor (Q3), and negative electrode is connected with an end of the 15 capacitor (C15).
9, impulsive sound according to claim 7 prevents circuit, it is characterized in that, described the tenth resistor (R10) is a thermistor.
10, impulsive sound according to claim 7 prevents circuit, it is characterized in that, described first metal-oxide-semiconductor field effect transistor (M1) is PMOS, its source electrode is connected the two ends of the tenth resistor (R10) respectively with drain electrode, its grid is coupled to the collector electrode of the 3rd transistor (Q3), makes described first metal-oxide-semiconductor field effect transistor (M1) conducting with the conducting of the 3rd transistor (Q3).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU200720118051XU CN201001104Y (en) | 2007-01-12 | 2007-01-12 | Impact sound preventing circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU200720118051XU CN201001104Y (en) | 2007-01-12 | 2007-01-12 | Impact sound preventing circuit |
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|---|---|
| CN201001104Y true CN201001104Y (en) | 2008-01-02 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU200720118051XU Expired - Fee Related CN201001104Y (en) | 2007-01-12 | 2007-01-12 | Impact sound preventing circuit |
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| CN (1) | CN201001104Y (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101290332B (en) * | 2008-05-14 | 2010-10-13 | 深圳创维－Rgb电子有限公司 | Voltage up-down detection circuit and method |
| CN101924970A (en) * | 2010-06-04 | 2010-12-22 | 深圳创维－Rgb电子有限公司 | Circuit for eliminating earphone plosion of liquid crystal display television |
| CN103702048A (en) * | 2013-12-27 | 2014-04-02 | 乐视致新电子科技（天津）有限公司 | Method and system for eliminating television noise |
| CN109671413A (en) * | 2019-02-26 | 2019-04-23 | 合肥京东方显示技术有限公司 | Booster circuit and shutdown circuit and their driving method and display device |
| CN116112846A (en) * | 2022-10-08 | 2023-05-12 | 广州市保伦电子有限公司 | Restarting impact sound eliminating circuit and audio circuit |
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2007
- 2007-01-12 CN CNU200720118051XU patent/CN201001104Y/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101290332B (en) * | 2008-05-14 | 2010-10-13 | 深圳创维－Rgb电子有限公司 | Voltage up-down detection circuit and method |
| CN101924970A (en) * | 2010-06-04 | 2010-12-22 | 深圳创维－Rgb电子有限公司 | Circuit for eliminating earphone plosion of liquid crystal display television |
| CN103702048A (en) * | 2013-12-27 | 2014-04-02 | 乐视致新电子科技（天津）有限公司 | Method and system for eliminating television noise |
| CN109671413A (en) * | 2019-02-26 | 2019-04-23 | 合肥京东方显示技术有限公司 | Booster circuit and shutdown circuit and their driving method and display device |
| CN109671413B (en) * | 2019-02-26 | 2020-11-13 | 合肥京东方显示技术有限公司 | Booster circuit, shutdown circuit, driving method thereof, and display device |
| CN116112846A (en) * | 2022-10-08 | 2023-05-12 | 广州市保伦电子有限公司 | Restarting impact sound eliminating circuit and audio circuit |
| CN116112846B (en) * | 2022-10-08 | 2024-01-30 | 广东保伦电子股份有限公司 | Restarting impact sound eliminating circuit and audio circuit |
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| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20080102 Termination date: 20150112 |
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| EXPY | Termination of patent right or utility model |