CN206533521U - A kind of loudspeaker DC voltage detects circuit - Google Patents
A kind of loudspeaker DC voltage detects circuit Download PDFInfo
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- CN206533521U CN206533521U CN201720070486.5U CN201720070486U CN206533521U CN 206533521 U CN206533521 U CN 206533521U CN 201720070486 U CN201720070486 U CN 201720070486U CN 206533521 U CN206533521 U CN 206533521U
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- voltage
- loudspeaker
- audio
- amplifier
- circuit
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Abstract
The utility model provides a kind of loudspeaker DC voltage detection circuit, and the DC voltage detection circuit includes：One reference signal generator, to produce a reference signal；One first comparison circuit, first voltage and the reference signal to receive audio-frequency amplifier output end；One second comparison circuit, second voltage and the reference signal to receive audio-frequency amplifier output end；One OR gate, its first input end and the second input are respectively connecting to the output end of first comparison circuit and the second comparison circuit, and first modulating signal and the second modulating signal are received respectively and output signal is produced；One counter, its input connects the output end of the OR gate, and its output end connects the audio-frequency amplifier, to count the output signal of the OR gate to determine testing result, and is locked and closed the audio-frequency amplifier when testing result is abnormal.The loudspeaker DC voltage detection circuit that the utility model is provided can determine whether whether amplifier output voltage is excessive and cause amplifier damage with the presence or absence of flip-flop and its output signal, to protect loudspeaker, prevents loudspeaker from burning.
Description
Technical field
The utility model is related to electronic circuit technology field, more particularly to a kind of loudspeaker DC voltage detection circuit.
Background technology
Loudspeaker is also known as " loudspeaker ", is a kind of very conventional electro-acoustic transducer device, and loudspeaker converts the electrical signal to sound
Ripple, is widely used in various kinds of equipment.The connection circuit of loudspeaker occur in use come off, open circuit, short circuit
Risk, so as to cause loudspeaker faults, influence is used.Therefore need to carry out speaker circuit detection and protection work.
Loudspeaker is generally by efficient audio-frequency amplifier driving work, and audio-frequency amplifier input is connected with electric capacity, such as
The capacitance damage of fruit audio-frequency amplifier input, will cause output end voltage difference excessive to damage loudspeaker；Meanwhile, audio is put
Pressure difference between the electric capacity of big two inputs of device is excessive, or output voltage has dc component will also damage loudspeaker.
In the prior art, it is typically only capable to detect one end of electric capacity.The external capacitor of input be able to may also be damaged
Bad the problem of, but electric capacity only one end can be connected to the input of audio-frequency amplifier, so judgement that can not be complete is across electric capacity two
Voltage on end, so can not correctly judge electric capacity quality.Meanwhile, prior art can not detect the direct current of audio-frequency amplifier into
Part.For example, Publication No. CN101975891A patent document provides a kind of external capacitor detection method and detection means, lead to
Cross comparing unit to judge the relative size of external capacitor and desired value, to detect whether external capacitor locates what normal work shape
State.But it two end points of one electric capacity must be all connected to chip internal during capacitance detecting and judged, when having two
During individual electric capacity, just must external 4 test points, for the audio-frequency amplifier few to pin, influence actual use.
Utility model content
For problem above, the utility model patent purpose is to devise a kind of loudspeaker DC voltage detection circuit,
It can determine whether whether amplifier output voltage is excessive and cause amplifier damage with the presence or absence of flip-flop and its output signal, with
Loudspeaker is protected, prevents loudspeaker from burning.
The specific technical scheme of the utility model is as follows：
A kind of loudspeaker DC voltage detects circuit, and the loudspeaker drives work by audio-frequency amplifier, and the audio is put
Two output ends of big device export first voltage and second voltage to loudspeaker, and the DC voltage detection circuit includes：
One reference signal generator, to produce a reference signal；
One first comparison circuit, first voltage and the reference signal to receive the audio-frequency amplifier output end,
And produce the first modulating signal；
One second comparison circuit, second voltage and the reference signal to receive the audio-frequency amplifier output end,
And produce the second modulating signal；
One OR gate, it has a first input end, one second input and an output end, its first input end and second defeated
Enter the output end that end is respectively connecting to first comparison circuit and the second comparison circuit, first modulating signal is received respectively
With the second modulating signal and produce output signal；
One counter, its input connects the output end of the OR gate, and its output end connects the audio-frequency amplifier, is used to
The output signal of the OR gate is counted to determine testing result, and the audio is locked and closed when testing result is abnormal and is amplified
Device.
Specifically, counter described in the utility model is the counter with lock function.
Specifically, audio-frequency amplifier described in the utility model is analogue amplifier, the audio-frequency amplifier amplifies for A classes
Device, class-b amplifier or class ab ammplifier.The reference signal generator is reference voltage generator, to produce a reference
Voltage；First comparison circuit and the second comparison circuit are respectively first comparator and the second comparator.
Specifically, audio-frequency amplifier described in the utility model is digital amplifier, the audio-frequency amplifier amplifies for D classes
Device.The reference signal generator is pwm signal generator, has the PWM reference signal of flip-flop to produce one；It is described
First comparison circuit and the second comparison circuit are respectively the first flip-flop and the second flip-flop.
The loudspeaker DC voltage detection circuit that the utility model is provided, compared with prior art, can determine whether that amplifier is defeated
Go out voltage whether excessive and cause amplifier damage with the presence or absence of flip-flop and its output signal, to protect loudspeaker, prevent
Only loudspeaker burns.And one electric capacity of its DC detecting only needs an end points to make a decision, and two electric capacity only need two end points,
It is easy to use；And be mainly used to judge direct current signal, it is not that the capacitance size for judging electric capacity can determine whether that direct current is believed
Number.
Brief description of the drawings
The utility model embodiment is described further referring to the drawings, wherein：
Fig. 1 is the application circuit of prior art audio-frequency amplifier；
Fig. 2 is application circuit of the present utility model；
Fig. 3 is the circuit diagram of the utility model embodiment one；
Fig. 4 is the result judgement figure of the utility model embodiment one；
Fig. 5 is the circuit diagram of the utility model embodiment two；
Fig. 6 is that the pwm signal of the utility model embodiment two judges schematic diagram；
Fig. 7 is the circuit diagram for the counter that the utility model has lock function.
Embodiment
The utility model is described in further detail with specific embodiment below in conjunction with the accompanying drawings.
The application circuit that Fig. 1 is prior art audio-frequency amplifier is referred to, loudspeaker is a passive device, it is necessary to by sound
Audio amplifier promotes generation sound, if amplifier differential output is with the presence of a DC voltage, easily causes loudspeaker and burns.
The reason for amplifier differential output is with the presence of DC voltage has two, and one is that input capacitance is problematic, and two be that amplifier circuit is different
Often, such as excessive offset voltage or output-stage circuit are impaired.Accordingly, it would be desirable to accurate decision circuitry failure, to loudspeaker electricity
Carry out detection and protection work in road.
Fig. 2 is referred to for application circuit of the present utility model, the utility model proposes a kind of loudspeaker DC voltage
Circuit is detected, the loudspeaker drives work by audio-frequency amplifier, and two output ends of the audio-frequency amplifier are exported to loudspeaker
First voltage and second voltage, a DC detection circuit are positioned over the differential output end of audio-frequency amplifier, are sent for detection in time
Whether the first voltage and second voltage signal for entering loudspeaker contain flip-flop, and judge whether output signal is excessive, main
It is used to protect loudspeaker.
Specifically, the DC voltage detection circuit includes：
One reference signal generator, to produce a reference signal；
One first comparison circuit, first voltage and the reference signal to receive the audio-frequency amplifier output end,
And produce the first modulating signal；
One second comparison circuit, second voltage and the reference signal to receive the audio-frequency amplifier output end,
And produce the second modulating signal；
One OR gate, it has a first input end, one second input and an output end, its first input end and second defeated
Enter the output end that end is respectively connecting to first comparison circuit and the second comparison circuit, first modulating signal is received respectively
With the second modulating signal and produce output signal；
One counter, its input connects the output end of the OR gate, and its output end connects the audio-frequency amplifier, is used to
The output signal of the OR gate is counted to determine testing result, and the audio is locked and closed when testing result is abnormal and is amplified
Device.The counter is the counter with lock function.
For different types of audio-frequency amplifier, different DC detection circuits can be carried out.
Embodiment one：
Specifically, audio-frequency amplifier described in the present embodiment be analogue amplifier, for example, class-a amplifier, class-b amplifier or
Person's class ab ammplifier.The circuit diagram that Fig. 3 is embodiment one is referred to, the reference signal generator is reference voltage generator,
To produce a reference voltage；First comparison circuit and the second comparison circuit are respectively that first comparator and second are compared
Device.
Specifically, carrying out first voltage OUTP, second voltage OUTN and reference voltage respectively using two comparators
Vref comparison, when first voltage OUTP or second voltage OUTN has one more than reference voltage Vref, OR gate is output as height
Level, then start counter.Because audio signal low-limit frequency is 20Hz, the cycle is 50ms, and half period is 25ms, so meter
The number device time is at least higher than the signal that 25ms can just have flip-flop at last.For example, the present embodiment set counter time as
200ms, that is, after 200ms, if OR gate output is still high level, counter output DCOFF switchs to high level, and
And counter controls lock-in amplifier, audio-frequency amplifier is closed, it is to avoid loudspeaker is exposed in DC voltage risk for a long time
And damage.
Refer to the result judgement figure that Fig. 4 is the present embodiment one, specially normal audio signal and anomalous audio signal
Voltage judges figure, such as first voltage OUTP is continued above reference voltage Vref when abnormal, then OR gate output RESET/ can be maintained
In high level, counter can keeping count.
Embodiment two：
Specifically, audio-frequency amplifier described in the present embodiment is digital amplifier, the audio-frequency amplifier is class-D amplifier.
The circuit diagram that Fig. 5 is the present embodiment two is referred to, the reference signal generator is pwm signal generator, to produce a tool
There is the PWM reference signal of flip-flop；First comparison circuit and the second comparison circuit are respectively the first flip-flop and second
Flip-flop.
The present embodiment uses digital amplifier, such as class-D amplifier, and output first voltage OUTP and second voltage OUTN is
PWM signal, principle is the generation PWM data signal by input simulated audio signal after high frequency triangle wave modulating signal,
The advantage of this class A amplifier A be high efficiency (>80%).Refer to Fig. 6 and judge schematic diagram for pwm signal, when there is no input signal,
The duty of first voltage OUTP pwm signal is 50%, when having input signal, and duty can be bigger than 50% or small, and the limit is then
100% and 0%.
Pwm signal generator produces PWMref signals, and what PWMref signals were represented is the PWM references for being loaded with flip-flop
Signal, such as 55%duty.When the duty of OUTP or OUTN one is more than 55%, flip-flop output Q1 or Q2 can switch to high electricity
It is flat, and OR gate output RESET/ can switch to high level, to start counter.When counting more than 200ms, if Q1 or Q2 are continuously
During high level, then it represents that detect direct current signal, this hour counter output DCOFF switchs to high level, and lock-in amplifier, will
Audio-frequency amplifier is closed.
The circuit diagram that Fig. 7 is the counter with lock function is referred to, input clock signals can be basic according to system
The pulse wave signal of demand is provided, for example, can be 500kHz.After flip-flop frequency elimination 131072, it can obtain 262ms's
Time.The time of counter can be set according to loudspeaker condition.
The DC detection circuit that the utility model is provided can detect audio-frequency amplifier output voltage, defeated to determine whether
Go out no flip-flop, may also be used for judging whether output signal is excessive, and be likely to result in the damage of loudspeaker.The utility model
DC detection circuit, detection one electric capacity only need an end points to make a decision, two electric capacity only need two end points, and this practicality
It is new to be mainly used to judge direct current signal, it is not that the capacitance size for judging electric capacity is known that whether there is direct current signal.
Embodiment of the present utility model described above, does not constitute the restriction to the utility model protection domain.
Any various other corresponding changes and deformation made according to technical concept of the present utility model, should be included in this practicality
In new scope of the claims.
Claims (8)
1. a kind of loudspeaker DC voltage detects circuit, the loudspeaker drives work, the audio amplification by audio-frequency amplifier
Two output ends of device export first voltage and second voltage to loudspeaker, it is characterised in that the DC voltage detects circuit bag
Include：
One reference signal generator, to produce a reference signal；
One first comparison circuit, to receive the first voltage and the reference signal of the audio-frequency amplifier output end, and is produced
Raw first modulating signal；
One second comparison circuit, to receive the second voltage and the reference signal of the audio-frequency amplifier output end, and is produced
Raw second modulating signal；
One OR gate, it has a first input end, one second input and an output end, its first input end and the second input
The output end of first comparison circuit and the second comparison circuit is respectively connecting to, first modulating signal and are received respectively
Two modulating signals simultaneously produce output signal；
One counter, its input connects the output end of the OR gate, and its output end connects the audio-frequency amplifier, to count
The output signal of the OR gate is locked and closed the audio-frequency amplifier to determine testing result when testing result is abnormal.
2. loudspeaker DC voltage according to claim 1 detects circuit, it is characterised in that the counter is with lock
Determine the counter of function.
3. the loudspeaker DC voltage detection circuit according to any one of claim 1 or 2, it is characterised in that the audio
Amplifier is analogue amplifier.
4. loudspeaker DC voltage according to claim 3 detects circuit, it is characterised in that the audio-frequency amplifier is A
Class A amplifier A, class-b amplifier or class ab ammplifier.
5. loudspeaker DC voltage according to claim 3 detects circuit, it is characterised in that the reference signal generator
For reference voltage generator, to produce a reference voltage；First comparison circuit and the second comparison circuit are respectively first
Comparator and the second comparator.
6. the loudspeaker DC voltage detection circuit according to any one of claim 1 or 2, it is characterised in that the audio
Amplifier is digital amplifier.
7. loudspeaker DC voltage according to claim 6 detects circuit, it is characterised in that the audio-frequency amplifier is D
Class A amplifier A.
8. loudspeaker DC voltage according to claim 6 detects circuit, it is characterised in that the reference signal generator
For pwm signal generator, there is the PWM reference signal of flip-flop to produce one；First comparison circuit and the second ratio
It is respectively the first flip-flop and the second flip-flop compared with circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720070486.5U CN206533521U (en) | 2017-01-20 | 2017-01-20 | A kind of loudspeaker DC voltage detects circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720070486.5U CN206533521U (en) | 2017-01-20 | 2017-01-20 | A kind of loudspeaker DC voltage detects circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN206533521U true CN206533521U (en) | 2017-09-29 |
Family
ID=59919133
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201720070486.5U Expired - Fee Related CN206533521U (en) | 2017-01-20 | 2017-01-20 | A kind of loudspeaker DC voltage detects circuit |
Country Status (1)
| Country | Link |
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| CN (1) | CN206533521U (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2018133564A1 (en) * | 2017-01-20 | 2018-07-26 | 深圳市中移联半导体科技有限公司 | Speaker dc voltage detection circuit |
| CN109218915A (en) * | 2018-09-05 | 2019-01-15 | 厦门傅里叶电子有限公司 | Digital power amplifier chip and its direct current protecting method with direct current protecting function |
| CN113391141A (en) * | 2020-03-12 | 2021-09-14 | 圣邦微电子（北京）股份有限公司 | Noise testing device and testing method |
| CN117491765A (en) * | 2023-10-10 | 2024-02-02 | 苏州纳芯微电子股份有限公司 | Direct current detection circuit and electronic equipment suitable for class D amplifier |
-
2017
- 2017-01-20 CN CN201720070486.5U patent/CN206533521U/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2018133564A1 (en) * | 2017-01-20 | 2018-07-26 | 深圳市中移联半导体科技有限公司 | Speaker dc voltage detection circuit |
| CN109218915A (en) * | 2018-09-05 | 2019-01-15 | 厦门傅里叶电子有限公司 | Digital power amplifier chip and its direct current protecting method with direct current protecting function |
| CN113391141A (en) * | 2020-03-12 | 2021-09-14 | 圣邦微电子（北京）股份有限公司 | Noise testing device and testing method |
| CN113391141B (en) * | 2020-03-12 | 2024-01-23 | 圣邦微电子（北京）股份有限公司 | Noise testing device and testing method |
| CN117491765A (en) * | 2023-10-10 | 2024-02-02 | 苏州纳芯微电子股份有限公司 | Direct current detection circuit and electronic equipment suitable for class D amplifier |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20190517 Address after: 518000 Guangdong Province, Futian District, Shenzhen, 1063 Xiangmei Road, Shuixie Flower Du Mingcuiju 2 20B Patentee after: Lin Qiliang Address before: 518000 No. 22 Huanping Road, Gaoqiao Community, Pingdi Street, Longgang District, Shenzhen City, Guangdong Province Patentee before: SHENZHEN ZYL SEMICONDUCTOR TECHNOLOGY Co.,Ltd. |
|
| TR01 | Transfer of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20170929 Termination date: 20220120 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |