CN208258050U - Mute control circuit for power failure - Google Patents
Mute control circuit for power failure Download PDFInfo
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- CN208258050U CN208258050U CN201820902914.0U CN201820902914U CN208258050U CN 208258050 U CN208258050 U CN 208258050U CN 201820902914 U CN201820902914 U CN 201820902914U CN 208258050 U CN208258050 U CN 208258050U
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Abstract
The utility model discloses a kind of mute control circuit for power failure comprising voltage comparator, first voltage output port, second voltage output port, mute control port and exports low level for the high level according to input and exports the power-fail detection circuit of high level according to the low level of input；The connection of the non-inverting input terminal of first voltage output port and voltage comparator, the connection of the inverting input terminal of second voltage output port and voltage comparator, the output end of voltage comparator and the input terminal of power-fail detection circuit connect, and the output end of power-fail detection circuit is connect with mute control port；During power down, the power down speed of first voltage output port is slower than the power down speed of second voltage output port；In non-power down, first voltage output port is output to the first voltage of non-inverting input terminal, lower than the second voltage that second voltage output port is output to inverting input terminal.The mute control circuit for power failure of the utility model can be improved the mute response speed of power down of circuit.
Description
Technical field
The utility model relates to mute circuit technical fields, more particularly, to a kind of mute control circuit for power failure.
Background technique
The existing electronic product (such as television set, set-top box) with sound-playing function during shutdown, electronic product
CPU can not to the power amplifier of electronic product carry out mute operation；And in electronic product shutdown, it is input to power amplifier electricity
The voltage signal on road can generate mutation (i.e. voltage reduces rapidly, such as voltage drops to 0V by 5V), such power amplifier it is defeated
Signal generates mutation out, and the mutation of this output signal will allow loudspeaker to generate the abnormal sound, to form noise.In order to keep away
Exempt from the generation of above situation, existing way is used for by designing a mute control circuit for power failure in electronic product
When detecting electronic product shutdown and power down occur, control power amplifier stops working immediately.
Referring to Figure 1, the circuit structure of current mute control circuit for power failure is general are as follows: including voltage input port Vin1
(connecting with the operating circuit all the way of electronic product), voltage input port Vin2, mute control port Vout are (with electronic product
Power amplifier module connection), resistance RA1, resistance RA2, resistance RA3, resistance RA4, resistance RA5, resistance RA6, diode DA1, capacitor
CA1, p-type triode QA1 and N-type triode QA2, the connection relationship of these components are as shown in Figure 1.Current power down is mute
The working principle of control circuit are as follows: in the non-power down of electronic product, the output voltage of voltage input port Vin1 has wherein all the way
It is lower after resistance RA1 and the partial pressure of resistance RA2, and is output to the anode of diode DA1, at this time diode current flow, and give
Capacitor CA1 charging；And the another way of the output voltage of voltage input port Vin1 is output to p-type triode QA1 by resistance RA3
Base stage, since the voltage of the base stage of p-type triode QA1 is higher than the voltage of emitter, p-type triode QA1 cut-off, so
N-type triode QA2 is also switched off, and mute control port Vout exports high level at this time, and the power amplifier module of electronic product works normally.
When electronic product power down, since capacitor CA1 makes the voltage of the emitter of p-type triode QA1 keep higher in a short time,
And the voltage of the base stage of p-type triode QA1 reduces rapidly, so p-type triode QA1 is connected, so that N-type triode QA2 is also led
Logical, control port Vout mute in this way exports low level mute control signal, so that the power amplifier module of electronic product is vertical
Stop working.
In existing mute control circuit for power failure, voltage input port Vin1 passes through the partial pressure of resistance RA1 and resistance RA2
It is output to the voltage of the emitter of p-type triode QA1 afterwards, can be exported well below voltage input port Vin1 by resistance RA3
To the voltage of the base stage of p-type triode QA1, in this way when the power down speed of the voltage of voltage input port Vin1 monitoring is slower,
Meeting so that circuit delays during power down output mute control signal, so as to cause circuit mute control operational failure and produce
Raw noise.
Utility model content
In view of the above-mentioned problems, can be improved the purpose of this utility model is to provide a kind of mute control circuit for power failure
The mute response speed of power down, so that it is guaranteed that the mute control work of circuit is not in failure.
To achieve the goals above, the utility model embodiment provides a kind of mute control circuit for power failure comprising electricity
Press comparator, first voltage output port, second voltage output port, mute control port and for according to input height electricity
It puts down and exports low level and export the power-fail detection circuit of high level according to the low level of input；
The first voltage output port is connect with the non-inverting input terminal of the voltage comparator, the second voltage output
Port is connect with the inverting input terminal of the voltage comparator, the output end of the voltage comparator and the power-fail detection circuit
Input terminal connection, the output end of the power-fail detection circuit connect with the mute control port；
During power down, the power down speed of the first voltage output port is faster than the power down of the second voltage output port
Degree is slow；In non-power down, the first voltage output port is output to the first voltage of the non-inverting input terminal, than described second
The second voltage that voltage output port is output to the inverting input terminal is low.
The mute control circuit for power failure provided by the embodiment of the utility model, in non-power down, (electronic product also exists
Normal power-up work), since the first voltage of the non-inverting input terminal is lower than the second voltage of the inverting input terminal, such institute
Voltage comparator output low level voltage is stated, and the power-fail detection circuit is then to the mute control port output high level electricity
Pressure, the power amplifier module of electronic product connecting with the mute control port works normally at this time；(i.e. electronic product during power down
Disconnect power supply), since the first voltage output port power down speed is slow, and the power down speed of the second voltage output port
Fastly, the second voltage of the inverting input terminal described in this way can be lower than the first voltage of the non-inverting input terminal after reducing rapidly, this
Shi Suoshu voltage comparator output high level voltage, and the power-fail detection circuit then exports low electricity to the mute control port
Ordinary telegram pressure thus triggers the power amplifier module and stops working immediately, to avoid the generation of noise.By upper analysis it is found that originally
Utility model embodiment compares two different circuit voltages of power down speed by setting voltage comparator, to touch during power down
The mute work of Power Generation Road, in this way can according to power down it is fireballing that all the way voltage come the mute work of trigger circuit, thus
The mute response speed of the power down of circuit can be improved, and then ensure that the mute control work of circuit is not in failure.
Preferably, the power-fail detection circuit includes N-type triode, tertiary voltage output port and first resistor；
The base stage of the N-type triode is connect with the output end of the voltage comparator, the emitter of the N-type triode
Ground connection, the collector of the N-type triode are connect by the first resistor with the tertiary voltage output port；It is described mute
Control port is connected between the first resistor and the collector of the N-type triode.
Preferably, the power-fail detection circuit further includes first capacitor；One end of the first capacitor is connected to described
Between one resistance and the collector of the N-type triode, the other end of the first capacitor is grounded.
Preferably, the power-fail detection circuit further includes second resistance and the second capacitor；The output of the voltage comparator
End is connect by the second resistance with the base stage of the N-type triode, and second capacitor is in parallel with the second resistance.
Preferably, the input voltage of the first voltage output port is 5V in non-power down, the second voltage output
The input voltage of port is 12V.
Preferably, the mute control circuit for power failure further includes bleeder circuit；
The second voltage output port is connect by the bleeder circuit with the inverting input terminal of the voltage comparator；
In non-power down, the second voltage output port is output to the reverse phase after the partial pressure of the bleeder circuit
The second voltage of input terminal is higher than the first voltage, and the absolute value of the first voltage and the difference of the second voltage is small
In or equal to preset threshold value.
Preferably, the threshold value is 1V.
Preferably, the bleeder circuit includes 3rd resistor and the 4th resistance；The second voltage output port passes through institute
It states 3rd resistor to connect with the inverting input terminal, one end of the 4th resistance is connected to the 3rd resistor and the reverse phase
Between input terminal, the other end of the 4th resistance is grounded.
Detailed description of the invention
It, below will be to attached needed in embodiment in order to illustrate more clearly of the technical solution of the utility model
Figure is briefly described, it should be apparent that, the accompanying drawings in the following description is only some embodiments of the utility model, for
For those of ordinary skill in the art, without creative efforts, it can also be obtained according to these attached drawings other
Attached drawing.
Fig. 1 is the structural schematic diagram of the mute control circuit for power failure of the prior art；
Fig. 2 is a kind of structural schematic diagram of mute control circuit for power failure provided by the embodiment of the utility model.
Specific embodiment
The following will be combined with the drawings in the embodiments of the present invention, carries out the technical scheme in the embodiment of the utility model
Clearly and completely describe, it is clear that the described embodiments are only a part of the embodiments of the utility model, rather than whole
Embodiment.Based on the embodiments of the present invention, those of ordinary skill in the art are without making creative work
Every other embodiment obtained, fall within the protection scope of the utility model.
Fig. 2 is referred to, the utility model embodiment provides a kind of mute control circuit for power failure, broadcasts applied to sound
In the electronic product of playing function comprising voltage comparator U1, first voltage output port Vn1, second voltage output port
Vn2, mute control port Vo and low level and defeated according to the low level of input is exported for the high level according to input
The power-fail detection circuit 1 of high level out；The non-inverting input terminal of the first voltage output port Vn1 and the voltage comparator U1
Connection, the second voltage output port Vn2 are connect with the inverting input terminal of the voltage comparator U1, the voltage comparator
The output end of U1 is connect with the input terminal of the power-fail detection circuit 1, the output end of the power-fail detection circuit 1 with it is described mute
Control port Vo connection.The slow-footed circuit connection of power down of the first voltage output port Vn1 and the electronic product, institute
The fireballing circuit connection of power down of second voltage output port Vn2 Yu the electronic product are stated, so during power down, described
The power down speed of one voltage output port Vn1 is slower than the power down speed of the second voltage output port Vn2.It is produced in the electronics
When the non-power down of product, the first voltage output port Vn1 is output to the first voltage of the non-inverting input terminal, than second electricity
The second voltage that pressure output port Vn2 is output to the inverting input terminal is low.
The working principle of the embodiment of the present invention mute control circuit for power failure are as follows: (electronic product also exists in non-power down
Normal power-up work), since the first voltage of the non-inverting input terminal is lower than the second voltage of the inverting input terminal, such institute
Voltage comparator U1 output low level voltage is stated, and the power-fail detection circuit 1 is then high to the mute control port Vo output
Level voltage, the power amplifier module of electronic product connecting with the mute control port Vo works normally at this time；During power down (i.e.
Electronic product disconnects power supply), since the first voltage output port Vn1 power down speed is slow, and the second voltage output end
The power down speed of mouth Vn2 is fast, and the second voltage of the inverting input terminal described in this way can be than the non-inverting input terminal after reducing rapidly
First voltage it is low, the voltage comparator U1 output high level voltage at this time, and the power-fail detection circuit 1 is then to described quiet
Sound control port Vo exports low level voltage, thus triggers the power amplifier module and stops working immediately, to avoid noise
It generates.
For the ease of the understanding to the utility model, provide the utility model as shown below more specific herein
Embodiment:
In the present embodiment, Fig. 2 is referred to, the power-fail detection circuit 1 includes N-type triode Q1, tertiary voltage output
Port Vn3 and first resistor R1；The base stage of the N-type triode Q1 is connect with the output end of the voltage comparator U1, the N
The emitter of type triode Q1 is grounded, and the collector of the N-type triode Q1 passes through the first resistor R1 and third electricity
Press output port Vn3 connection；The mute control port Vo is connected to the collection of the first resistor R1 Yu the N-type triode Q1
Between electrode.Wherein, in non-power down, since the voltage comparator U1 exports low level voltage, the N-type triode
Q1 cut-off, the mute control port Vo output high level voltage, at this time the electronic product with the mute control port
The power amplifier module (not shown) of Vo connection works normally；During power down, since the voltage comparator U1 can export high level electricity
Pressure, therefore the N-type triode Q1 is connected, the mute control port Vo can export low level voltage, to trigger the function
Amplification module stops working immediately.
In the present embodiment, Fig. 2 is referred to, the power-fail detection circuit 1 further includes first capacitor C1；The first capacitor
One end of C1 is connected between the first resistor R1 and the collector of the N-type triode Q1, and the first capacitor C1's is another
One end ground connection.Wherein, the first capacitor C1 can make the voltage signal for being output to the mute control port VoVo more steady
It is fixed.
In the present embodiment, Fig. 2 is referred to, the power-fail detection circuit 1 further includes second resistance R2 and the second capacitor C2；
The output end of the voltage comparator U1 is connect by the second resistance R2 with the base stage of the N-type triode Q1, and described
Two capacitor C2 are in parallel with the second resistance R2.Wherein, the second resistance R2 can play the role of current limliting, second electricity
Holding C2 is then to reduce the impedance to high-frequency signal.
It should be noted that the power-fail detection circuit 1 can also be for the circuit that is made of metal-oxide-semiconductor or by multiple triodes
The circuit etc. of composition " exports low level and defeated according to the low level of input according to the high level of input as long as can be realized
High level out " is not specifically limited herein.
In the present embodiment, in non-power down, the input voltage of the first voltage output port Vn1 is 5V, described the
The input voltage of two voltage output port Vn2 is 12V.Certainly, the first voltage output port Vn1 and the second voltage are defeated
Exit port Vn2 can also be other voltage values.
In the present embodiment, Fig. 2 is referred to, the mute control circuit for power failure further includes bleeder circuit 2；Second electricity
Pressure output port Vn2 is connect by the bleeder circuit 2 with the inverting input terminal of the voltage comparator U1；Wherein, described point
The effect of volt circuit 2 is: on the one hand, in non-power down, so that the second voltage output port Vn2 passes through the bleeder circuit
The second voltage that the inverting input terminal is output to after 2 partial pressure is higher than the first voltage；On the other hand, in non-power down and
When one voltage output port Vn1 differs larger with the output voltage of both second voltage output port Vn2, so that first electricity
The absolute value of pressure and the difference of the second voltage be less than or equal to preset threshold value (i.e. in non-power down, the first voltage
Very little is differed with the second voltage), so during power down, since the second voltage output port Vn2 power down speed is fast, and
The first voltage differs very little with the second voltage, to can make the second voltage promptly than the first voltage
It is small, the mute response speed of the power down of circuit can be improved in this way, the mute control work for effectively ensuring circuit will not go out
Now fail.Preferably, the threshold value is 1V, certain threshold value can also be other lesser numerical value (such as 0.5V).
Specifically, Fig. 2 is referred to, the bleeder circuit 2 includes 3rd resistor R3 and the 4th resistance R4；The second voltage
Output port Vn2 is connect by the 3rd resistor R3 with the inverting input terminal, and one end of the 4th resistance R4 is connected to
Between the 3rd resistor R3 and the inverting input terminal, the other end of the 4th resistance R4 is grounded.
In conclusion the mute control circuit for power failure provided by the embodiment of the utility model, by the way that the voltage is arranged
Comparator U1 in this way may be used to compare two different circuit voltages of power down speed with the mute work of trigger circuit during power down
With according to power down it is fireballing that voltage is mute so as to the power down that improves circuit come the mute work of trigger circuit all the way
Response speed, and then ensure that the mute control work of circuit is not in failure.
Above description is only a specific implementation of the present invention, but the protection scope of the utility model is not limited to
In this, any those skilled in the art is in technical scope disclosed by the utility model, the change that can readily occur in
Change or replace, should be covered within the scope of the utility model.Therefore, the protection scope of the utility model should be with described
Subject to scope of protection of the claims.
Claims (8)
1. a kind of mute control circuit for power failure, which is characterized in that including voltage comparator, first voltage output port, the second electricity
It presses output port, mute control port and exports low level and the low level according to input for the high level according to input
And export the power-fail detection circuit of high level；
The first voltage output port is connect with the non-inverting input terminal of the voltage comparator, the second voltage output port
It is connect with the inverting input terminal of the voltage comparator, the output end of the voltage comparator is defeated with the power-fail detection circuit
Enter end connection, the output end of the power-fail detection circuit is connect with the mute control port；
During power down, power down speed of the power down speed of the first voltage output port than the second voltage output port
Slowly；In non-power down, the first voltage output port is output to the first voltage of the non-inverting input terminal, than second electricity
The second voltage that pressure output port is output to the inverting input terminal is low.
2. mute control circuit for power failure as described in claim 1, which is characterized in that the power-fail detection circuit includes N-type three
Pole pipe, tertiary voltage output port and first resistor；
The base stage of the N-type triode is connect with the output end of the voltage comparator, and the emitter of the N-type triode connects
The collector on ground, the N-type triode is connect by the first resistor with the tertiary voltage output port；The mute control
Port processed is connected between the first resistor and the collector of the N-type triode.
3. mute control circuit for power failure as claimed in claim 2, which is characterized in that the power-fail detection circuit further includes first
Capacitor；One end of the first capacitor is connected between the first resistor and the collector of the N-type triode, and described first
The other end of capacitor is grounded.
4. mute control circuit for power failure as claimed in claim 2, which is characterized in that the power-fail detection circuit further includes second
Resistance and the second capacitor；The output end of the voltage comparator is connected by the second resistance and the base stage of the N-type triode
It connects, second capacitor is in parallel with the second resistance.
5. mute control circuit for power failure as described in claim 1, which is characterized in that in non-power down, the first voltage is defeated
The input voltage of exit port is 5V, and the input voltage of the second voltage output port is 12V.
6. such as mute control circuit for power failure described in any one of claim 1 to 5, which is characterized in that further include bleeder circuit；
The second voltage output port is connect by the bleeder circuit with the inverting input terminal of the voltage comparator；
In non-power down, the second voltage output port is output to the anti-phase input after the partial pressure of the bleeder circuit
The second voltage at end is higher than the first voltage, and the absolute value of the difference of the first voltage and the second voltage be less than or
Equal to preset threshold value.
7. mute control circuit for power failure as claimed in claim 6, which is characterized in that the threshold value is 1V.
8. mute control circuit for power failure as claimed in claim 6, which is characterized in that the bleeder circuit include 3rd resistor and
4th resistance；The second voltage output port is connect by the 3rd resistor with the inverting input terminal, the 4th electricity
One end of resistance is connected between the 3rd resistor and the inverting input terminal, the other end ground connection of the 4th resistance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820902914.0U CN208258050U (en) | 2018-06-11 | 2018-06-11 | Mute control circuit for power failure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820902914.0U CN208258050U (en) | 2018-06-11 | 2018-06-11 | Mute control circuit for power failure |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN208258050U true CN208258050U (en) | 2018-12-18 |
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ID=64654119
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201820902914.0U Active CN208258050U (en) | 2018-06-11 | 2018-06-11 | Mute control circuit for power failure |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN208258050U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109884927A (en) * | 2019-03-21 | 2019-06-14 | 高创(苏州)电子有限公司 | A kind of control circuit and its control method, electronic equipment |
-
2018
- 2018-06-11 CN CN201820902914.0U patent/CN208258050U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109884927A (en) * | 2019-03-21 | 2019-06-14 | 高创(苏州)电子有限公司 | A kind of control circuit and its control method, electronic equipment |
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