WO2016095245A1

WO2016095245A1 - Loudspeaker driving signal abnormality detection circuit and loudspeaker protection circuit

Info

Publication number: WO2016095245A1
Application number: PCT/CN2014/094627
Authority: WO
Inventors: 古伟锋; 王安伟; 范存源
Original assignee: 深圳Tcl数字技术有限公司
Priority date: 2014-12-18
Filing date: 2014-12-23
Publication date: 2016-06-23
Also published as: CN204291350U

Abstract

Disclosed is a loudspeaker driving signal abnormality detection circuit, comprising: a first detection circuit, a second detection circuit, an electronic switch, and an output circuit; both positive output ends of an amplifier first sound channel and an amplifier second sound channel are connected to the first detection circuit; both negative output ends of the amplifier first sound channel and the amplifier second sound channel are connected to the second detection circuit; a first end of the electronic switch is connected to the first detection circuit and the second detection circuit respectively, and a second end of the electronic switch is connected to the output circuit; when an amplifier voltage signal outputted to the loudspeaker is detected to be higher than a preset voltage value by at least one of the first detection circuit and the second detection circuit, the electronic switch is triggered to control the output circuit to output an abnormal signal. Also disclosed is a loudspeaker protection circuit. The present invention detects an abnormal voltage signal outputted to the loudspeaker, thus avoiding loudspeaker damage due to a higher amplifier output.

Description

Speaker drive signal abnormality detecting circuit and speaker protection circuit

Technical field

The invention relates to a speaker driving signal abnormality detecting circuit and a speaker protection circuit.

Background technique

The speaker is an indispensable part of the sound, and it mainly bears the sound output of the sound.

At present, the driver (amplifier) of the speaker in the audio is basically a complementary push-pull output. The output mode is to add an AC signal (sound signal) based on a certain DC level (used to drive the speaker). On the speaker, make the speaker sound. Although this method is more efficient, it has high voltage resistance requirements for the speaker. When the driving signal is unstable or too strong, the speaker is easily damaged.

Summary of the invention

The main object of the present invention is to provide a speaker driving signal abnormality detecting circuit and a speaker protection circuit, which can perform abnormal monitoring on a voltage signal output from a power amplifier to a speaker to avoid speaker damage.

To achieve the above object, the present invention provides a speaker driving signal abnormality detecting circuit for detecting a voltage signal output from a power amplifier to a speaker, wherein the speaker driving signal abnormality detecting circuit includes a first detecting circuit, a second detecting circuit, an electronic switch, and An output circuit, wherein the first channel of the power amplifier and the positive output terminal of the second channel are connected to the first detecting circuit; the first channel of the power amplifier and the negative output terminal of the second channel are connected to the a second detecting circuit; a first end of the electronic switch is respectively connected to the first detecting circuit and the second detecting circuit, a second end of the electronic switch is connected to the output circuit; and the first detecting circuit is And when at least one of the second detecting circuits detects that the voltage signal output from the power amplifier to the speaker is higher than the preset voltage value, triggering the electronic switch to be turned on to control the output circuit to output an abnormal signal.

Preferably, the first detecting circuit comprises a first power supply, a first resistor, a second resistor and a first switching tube, and one end of the first resistor and one end of the second resistor are interconnected, the first resistor The other end is connected to the positive output end of the first channel of the power amplifier, and the other end of the second resistor is connected to the positive output end of the second channel of the power amplifier; the base of the first switch tube One end of the first resistor and the second resistor interconnection are connected; an emitter of the first switch tube is connected to the first power supply, a collector of the first switch tube and a first end of the electronic switch End connection.

Preferably, the second detecting circuit includes a second power supply, a third resistor, a fourth resistor and a second switch, and one end of the third resistor is interconnected with one end of the fourth resistor, and the third resistor The other end is connected to the negative output end of the first channel of the power amplifier, and the other end of the second resistor is connected to the negative output end of the second channel of the power amplifier; the base of the second switch tube is One end of the third resistor and the fourth resistor interconnection are connected; an emitter of the second switch tube is connected to the second power supply, and a collector of the second switch tube and the first of the electronic switch End connection.

Preferably, the electronic switch includes a third power supply and a third switch, the base of the third switch being the first end of the electronic switch; the emitter of the third switch and the third power supply Connected, the collector of the third switch tube is the second end of the electronic switch.

Preferably, the output circuit has a start end connected to the second end of the electronic switch and an output end for outputting a preset abnormality signal; the output circuit includes a fourth power supply, a fourth switch, and a fifth a resistor, a base of the fourth switch tube is a start end of the output circuit, and a collector of the fourth switch tube is connected to the fourth power supply via the fifth resistor, and the fourth switch tube The emitter is grounded; the collector of the fourth switch is the output of the output circuit.

Preferably, the first power supply, the second power supply, the third power supply, and the fourth power supply are the same DC power supply.

Preferably, the first detecting circuit further includes a first capacitor, a sixth resistor, a seventh resistor, an eighth resistor and a ninth resistor, one end of the first capacitor is connected to the base of the first switch tube, and the other end is connected Grounding, one end of the sixth resistor is connected to the base of the first switch tube, and the other end is grounded via the seventh resistor; the eighth resistor is connected between the collector of the first switch tube and the ground, The ninth resistor is connected between the collector of the first switching transistor and the base of the third switching transistor.

Preferably, the second detecting circuit further includes a second capacitor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor and a third capacitor, and one end of the second capacitor and the second switch tube a base connection, the other end is grounded, one end of the tenth resistor is connected to the base of the second switch tube, the other end is grounded via the eleventh resistor; the twelfth resistor is connected to the second switch Between the collector of the tube and the ground, the thirteenth resistor is connected between the collector of the second switching tube and the base of the third switching tube; one end of the third capacitor and the first The output ends of the two power supplies and the collectors of the second switch are respectively connected, and the other end of the third capacitor is grounded.

Preferably, the output circuit further includes a fourteenth resistor, a fifteenth resistor and a fourth capacitor, wherein the fourteenth resistor is connected to the collector of the third switch tube and the base of the fourth switch tube between. One end of the fifteenth resistor is connected to the base of the fourth switch tube, and the other end is grounded; one end of the fourth capacitor is connected to the collector of the fourth switch tube, and the other end is grounded.

Preferably, the first switch tube, the second switch tube and the third switch tube are PNP type triode tubes; and the fourth switch tube is an NPN type triode tube.

The invention also provides a speaker protection circuit comprising a power amplifier, a first speaker and a second speaker, the power amplifier having a first channel and a second channel, the first channel having a first positive output and a first negative output The second channel has a second positive output terminal and a second negative output terminal, and the power amplifier is electrically connected to the first speaker through the first positive output terminal and the first negative output terminal; The second positive output terminal and the second negative output terminal are electrically connected to the second speaker; the speaker protection circuit further includes a control circuit and a speaker drive signal abnormality detecting circuit as described above, the first positive output of the power amplifier The first detection circuit of the speaker driving signal abnormality detecting circuit is connected to both the terminal and the second positive output terminal; the first negative output terminal and the second negative output terminal of the power amplifier are connected to the second detection of the speaker driving signal abnormality detecting circuit An output of the output circuit of the speaker driving signal abnormality detecting circuit is connected to the control circuit; the speaker driving letter The abnormality detecting circuit detects a voltage signal outputted by the power amplifier to the speaker, and outputs a voltage abnormality signal to the control circuit when the output voltage of the power amplifier is higher than a preset voltage value, and the control circuit is configured according to the voltage The abnormal signal cuts off the output of the amplifier or adjusts the output of the amplifier.

The invention detects that the power signal outputted to the speaker by the first detecting circuit and the second detecting circuit, and triggers the electronic switch to be turned on when the voltage signal on any channel exceeds a preset voltage value to control the The output circuit outputs an abnormal signal to detect the abnormal signal output from the power amplifier to the speaker. Thus, the post-processing circuit can adjust the output of the power amplifier or cut off the output of the power amplifier according to the abnormal signal to avoid overvoltage damage of the speaker.

DRAWINGS

1 is a block diagram showing the circuit structure of an embodiment of a speaker driving signal abnormality detecting circuit according to the present invention;

2 is a schematic diagram showing the circuit structure of the speaker driving signal abnormality detecting circuit shown in FIG. 1;

3 is a block diagram showing the circuit structure of the speaker driving signal abnormality detecting circuit shown in FIG. 2 applied to the speaker protection circuit.

The implementation, functional features, and advantages of the present invention will be further described in conjunction with the embodiments.

detailed description

It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The present invention provides a speaker driving signal abnormality detecting circuit for detecting whether a voltage signal output from a power amplifier to a speaker is abnormal, and the voltage signal includes a DC level signal for driving the operation of the speaker and a sound signal loaded at the DC level. Wherein, the power amplifier has a first channel and a second channel, and the first channel and the second channel both have a positive output terminal and a negative output terminal.

Referring to FIG. 1 and FIG. 2, in an embodiment, the speaker driving signal abnormality detecting circuit includes a first detecting circuit 11, a second detecting circuit 12, an electronic switch 13, and an output circuit 14, the first channel of the power amplifier And the positive output terminal of the second channel is connected to the first detecting circuit 11; the first channel of the power amplifier and the negative output terminal of the second channel are connected to the second detecting circuit 12; the electronic switch a first end of the first detection circuit 11 and a second detection circuit 12, the second end of the electronic switch 13 being connected to the output circuit 14, and the first detection circuit 11 and the When at least one of the second detecting circuits 12 detects that the voltage signal output from the power amplifier to the speaker is lower than the preset voltage value, the electronic switch 13 is triggered to be turned on to control the output circuit 14 to output an abnormal signal. When the first detecting circuit 11 and the second detecting circuit 12 detect that the voltage signal output from the power amplifier to the speaker is normal, the output circuit 14 has no signal output.

It can be understood that the power amplifier is a complementary push-pull output, that is, when the voltage signal outputted from the positive output terminal of the first channel is high, the voltage signal outputted by the negative output terminal of the first channel is low, and The second channel works the same as the first channel and will not be described here. Therefore, if the first channel and the second channel have a positive output or the output voltage of the negative output is high, the voltage outputted from the other output of the corresponding channel will be low. When the voltage signal output from the power amplifier to the speaker is higher than the preset voltage value, the first detecting circuit 11 or the second detecting circuit 12 outputs a trigger signal for triggering the electronic switch 13 to be turned on. When the electronic switch 13 is turned on, the control output circuit 14 outputs an abnormality. The signal, that is, the voltage signal output to the speaker is determined to be too high, the output of the power amplifier needs to be adjusted, or the output of the power amplifier needs to be cut off to protect the speaker.

The speaker driving signal abnormality detecting circuit of the present invention detects the voltage signal output from the power amplifier to the speaker by setting the first detecting circuit 11 and the second detecting circuit 12, and triggers the voltage signal on any channel when the voltage signal exceeds a preset voltage value. The electronic switch 13 is turned on to control the output circuit 14 to output an abnormal signal, thereby realizing the detection of the abnormal signal outputted by the power amplifier to the speaker, so that the latter processing circuit can adjust the power amplifier output according to the abnormal signal or cut off the power amplifier output, thereby avoiding the speaker passing. Pressure damage.

Based on the above embodiment, in a further embodiment, the first detecting circuit 11 includes a first power supply VCC1, a first resistor R1, a second resistor R2, and a first switching transistor Q1. In this embodiment, the first switching transistor Q1 is preferably a PNP type triode.

One end of the first resistor R1 and one end of the second resistor R2 are interconnected, and the other end of the first resistor R1 is connected to a positive output end of the first channel of the power amplifier, and the second resistor R2 The other end is connected to the positive output terminal of the second channel of the power amplifier; the base of the first switch transistor Q1 is connected to one end of the first resistor R1 and the second resistor R2; the first The emitter of the switching transistor Q1 is connected to the first power supply VCC1, and the collector of the first switching transistor Q1 is connected to the first end of the electronic switch 13.

Based on the above embodiment, in a further embodiment, the second detecting circuit 12 includes a second power supply VCC2, a third resistor R3, a fourth resistor R4, and a second switching transistor Q2. In this embodiment, the second switching transistor Q2 is preferably a PNP type triode.

The one end of the third resistor R3 is interconnected with one end of the fourth resistor R4, and the other end of the third resistor R3 is connected to the negative output end of the first channel of the power amplifier, and the second resistor R2 The other end is connected to the negative output terminal of the second channel of the power amplifier; the base of the second switch transistor Q2 is connected to one end of the third resistor R3 and the fourth resistor R4; the second The emitter of the switching transistor Q2 is connected to the second power supply VCC2, and the collector of the second switching transistor Q2 is connected to the first end of the electronic switch 13.

The electronic switch 13 includes a third power supply VCC3 and a third switch Q3. In this embodiment, the third switching transistor Q3 is preferably a PNP type triode.

The base of the third switch tube Q3 is the first end of the electronic switch 13; the emitter of the third switch tube Q3 is connected to the third power supply VCC3, and the third switch tube Q3 The collector is the second end of the electronic switch 13.

The output circuit 14 has a start end connected to the second end of the electronic switch 13 and an output end Out for outputting an abnormal signal; the output circuit 14 includes a fourth power supply VCC4, a fourth switch Q4, and a fifth a resistor R5, the base of the fourth switch tube Q4 is the start end of the output circuit 14, and the collector of the fourth switch tube Q4 is connected to the fourth power supply VCC4 via the fifth resistor R5. The emitter of the fourth switching transistor Q4 is grounded; the collector of the fourth switching transistor Q4 is the output of the output circuit 14. The fourth switching transistor Q4 preferably uses an NPN type triode.

It should be noted that the first power supply VCC1, the second power supply VCC2, the third power supply VCC3, and the fourth power supply VCC4 may be implemented by using the same DC power supply to save circuit cost.

In addition, in a further embodiment, the first detecting circuit 11 further includes a first capacitor C1, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, and a ninth resistor R9, one end of the first capacitor C1. Connected to the base of the first switching transistor Q1, the other end is grounded, one end of the sixth resistor R6 is connected to the base of the first switching transistor Q1, and the other end is connected to the ground via the seventh resistor R7; The eight resistor R8 is connected between the collector of the first switching transistor Q1 and the ground, and the ninth resistor R9 is connected between the collector of the first switching transistor Q1 and the base of the third switching transistor Q3.

The second detecting circuit 12 further includes a second capacitor C2, a third capacitor C3, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, and a thirteenth resistor R13.

Wherein, one end of the second capacitor C2 is connected to the base of the second switch tube Q2, and the other end is grounded, one end of the tenth resistor R10 is connected to the base of the second switch tube Q2, and the other end is connected to the other end. The eleventh resistor R11 is connected to the ground; the twelfth resistor R12 is connected between the collector of the second switch transistor Q2 and the ground, and the thirteenth resistor R13 is connected to the collector of the second switch transistor Q2. One end of the third switch tube Q3; one end of the third capacitor C3 is respectively connected to the output end of the second power supply VCC2 and the collector of the second switch tube Q2, the third The other end of the capacitor C3 is grounded.

The output circuit 14 further includes a fourteenth resistor R14, a fifteenth resistor R15, and a fourth capacitor C4.

The fourteenth resistor R14 is connected between the collector of the third switching transistor Q3 and the base of the fourth switching transistor Q4. One end of the fifteenth resistor R15 is connected to the base of the fourth switch tube Q4, and the other end is grounded; one end of the fourth capacitor C4 is connected to the collector of the fourth switch tube Q4, and the other end is grounded. The fourth capacitor C4 is a filter capacitor for filtering the signal outputted by the output terminal Out.

1 and 2, the specific circuit principle of the present invention is as follows:

As shown in Fig. 2, where Rout+ is the positive output terminal of the first channel of the power amplifier, Rout- is the negative output terminal of the first channel of the power amplifier, Lout+ is the positive output terminal of the second channel of the power amplifier, and Lout- is the power amplifier The negative output of the second channel. Since the Rout+ output voltage signal is low, the corresponding Rout-output will increase; Lout+ and Lout- are similar, and will not be described here. Therefore, when the voltage signal of any one or more of Rout+, Rout-, Lout+, and Lout- is lower or higher, the speaker is affected, and the present invention is based on this, as long as Rout+, Rout-, When one of Lout+ and Lout- is abnormally high, an abnormal signal is output, so that the latter circuit can know that the output of the power amplifier is abnormal. By cutting off the output of the power amplifier or adjusting the output of the power amplifier to prevent the speaker from overburning.

Specifically, when the outputs of Rout+, Rout-, Lout+, and Lout- are normal, the first switch tube Q1 and the second switch tube Q2 are both turned off, and at this time, the third switch tube Q3 is turned on, and the fourth switch tube Q4 is turned on. The output terminal Out of the output circuit 14 has no signal output.

When one or both of Rout+ and Lout+ output are high, the first switching transistor Q1 in the first detecting circuit 11 is turned off, and a low level signal is output. Since Lout+ and Lout- are complementary to the Rout+ and Lout+ outputs, one or both of Lout+ and Lout- will be output low. At this time, the second switch Q2 in the second detection module is turned on, and a high level signal is output. To the third switch tube Q3, the third switch tube Q3 is turned off, correspondingly, the fourth switch tube Q4 in the output module is turned off, and the output end Out of the output module outputs the voltage signal of the fourth power supply source VCC4, and the voltage signal is The abnormal signal output by the output circuit 14.

Similarly, when one or both of Rout- and Lout- are output low, the second switching transistor Q2 in the second detecting circuit 12 is turned off, and a low level signal is output. Since Rout+ and Lout+ are complementary to the Lout+ and Lout- outputs, one or both of Rout+ and Lout+ will be output low. At this time, the first switch Q1 in the first detection module is turned on, and a high level signal is output to The third switch tube Q3 and the third switch tube Q3 are turned off. Correspondingly, the fourth switch tube Q4 in the output module is turned off, and the output terminal Out of the output module outputs a voltage signal of the fourth power supply source VCC4, and the voltage signal is output. The abnormal signal output by the circuit 14.

In summary, when the circuit of the present invention detects that one of the Rout+, Rout-, Lout+, and Lout- ports is abnormally high, an abnormal signal is output, so that the latter circuit can know that the power amplifier output is abnormal, by cutting off the power amplifier output or adjusting the power amplifier. Output, so that the speaker can be prevented from overburning.

The present invention further provides a speaker protection circuit. Referring to FIG. 3, the speaker protection circuit includes a power amplifier 100, a first speaker 200, a second speaker 300, a control circuit 400, and the aforementioned speaker driving signal abnormality detecting circuit 500; Having a first channel and a second channel, the first channel has a first positive output (refer to Rout+ in FIG. 2) and a first negative output (refer to Rout- in FIG. 2), the second channel has a second positive output terminal (refer to Lout+ in FIG. 2) and a second negative output terminal (refer to Lout- in FIG. 2), wherein the power amplifier 100 passes through the first positive output terminal and the first negative output terminal The first speaker 300 is electrically connected; the power amplifier 100 is electrically connected to the second speaker 300 through the second positive output terminal and the second negative output terminal; the first positive output terminal and the second positive output of the power amplifier 100 The terminal is connected to the first detecting circuit 11 of the speaker driving signal abnormality detecting circuit 500; the first negative output terminal and the second negative output terminal of the power amplifier 100 are connected to the second detecting of the speaker driving signal abnormality detecting circuit 500 a circuit 12; an output end of the output circuit 14 of the speaker driving signal abnormality detecting circuit 500 is connected to the control circuit 400; the speaker driving signal abnormality detecting circuit 500 detects a voltage signal output from the power amplifier 100 to the speaker, and When any one of the output voltages of the power amplifier 100 is higher than the preset voltage value, the voltage abnormality signal is outputted to the control circuit 400, and the control circuit 400 cuts off the output of the power amplifier 100 or adjusts the output of the power amplifier 100 according to the voltage abnormality signal.

It can be understood that since the above-mentioned speaker driving signal abnormality detecting circuit 500 is used in the speaker protection circuit, even if the output voltage of the power amplifier 100 is high during the operation of the speaker protection circuit, the problem of burning the speaker does not occur. , to avoid user losses and improve product quality.

The above are only the preferred embodiments of the present invention, and are not intended to limit the scope of the invention, and the equivalent structure or equivalent process transformations made by the description of the present invention and the drawings are directly or indirectly applied to other related technical fields. The same is included in the scope of patent protection of the present invention.

Claims

A speaker driving signal abnormality detecting circuit for detecting a voltage signal outputted from a power amplifier to a speaker, wherein the speaker driving signal abnormality detecting circuit comprises a first detecting circuit, a second detecting circuit, an electronic switch and an output circuit, The first channel of the power amplifier and the positive output of the second channel are both connected to the first detecting circuit; the first channel of the power amplifier and the negative output of the second channel are connected to the second detecting circuit a first end of the electronic switch is respectively connected to the first detecting circuit and a second detecting circuit, and a second end of the electronic switch is connected to the output circuit; in the first detecting circuit and the first When at least one of the two detecting circuits detects that the voltage signal output from the power amplifier to the speaker is higher than the preset voltage value, the electronic switch is triggered to be turned on to control the output circuit to output an abnormal signal.
The speaker driving signal abnormality detecting circuit according to claim 1, wherein the first detecting circuit comprises a first power supply, a first resistor, a second resistor and a first switching tube, and one end of the first resistor Interconnecting with one end of the second resistor, the other end of the first resistor is connected to the positive output of the first channel of the power amplifier, and the other end of the second resistor is opposite to the second channel of the power amplifier a positive output terminal is connected; a base of the first switch tube is connected to one end of the first resistor and the second resistor; and an emitter of the first switch tube is connected to the first power supply, A collector of the first switching transistor is coupled to the first end of the electronic switch.
The speaker driving signal abnormality detecting circuit according to claim 2, wherein the second detecting circuit comprises a second power supply, a third resistor, a fourth resistor and a second switch, one end of the third resistor Interconnecting with one end of the fourth resistor, the other end of the third resistor is connected to the negative output of the first channel of the power amplifier, and the other end of the second resistor is opposite to the second channel of the power amplifier a base of the second switch is connected to an end of the third resistor and the fourth resistor; and an emitter of the second switch is connected to the second power supply, A collector of the second switching transistor is coupled to the first end of the electronic switch.
The speaker driving signal abnormality detecting circuit according to claim 3, wherein the electronic switch comprises a third power supply and a third switch, and the base of the third switch is the first end of the electronic switch; The emitter of the third switch tube is connected to the third power supply, and the collector of the third switch tube is the second end of the electronic switch.
A speaker driving signal abnormality detecting circuit according to claim 4, wherein said output circuit has a start end connected to a second end of said electronic switch and an output end for outputting a preset abnormal signal; The output circuit includes a fourth power supply, a fourth switch, and a fifth resistor. The base of the fourth switch is the start end of the output circuit, and the collector of the fourth switch is connected to the fifth resistor. The fourth power supply is connected, the emitter of the fourth switch is grounded, and the collector of the fourth switch is an output of the output circuit.
The speaker driving signal abnormality detecting circuit according to claim 5, wherein the first power supply source, the second power supply source, the third power supply source, and the fourth power supply source are the same DC power source.
The speaker driving signal abnormality detecting circuit according to claim 6, wherein the first detecting circuit further comprises a first capacitor, a sixth resistor, a seventh resistor, an eighth resistor, and a ninth resistor, the first One end of the capacitor is connected to the base of the first switch tube, and the other end is grounded, one end of the sixth resistor is connected to the base of the first switch tube, and the other end is grounded via the seventh resistor; the eighth resistor is connected The ninth resistor is connected between the collector of the first switching transistor and the base of the third switching transistor between the collector of the first switching transistor and the ground.
The speaker driving signal abnormality detecting circuit according to claim 7, wherein the second detecting circuit further comprises a second capacitor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, and a a third capacitor, one end of the second capacitor is connected to the base of the second switch tube, and the other end is grounded, one end of the tenth resistor is connected to the base of the second switch tube, and the other end is connected to the eleventh resistor Grounded; the twelfth resistor is connected between the collector of the second switch tube and the ground, and the thirteenth resistor is connected to the collector of the second switch tube and the base of the third switch tube One end of the third capacitor is respectively connected to an output end of the second power supply and a collector of the second switch, and the other end of the third capacitor is grounded.
The speaker driving signal abnormality detecting circuit according to claim 8, wherein the output circuit further comprises a fourteenth resistor, a fifteenth resistor and a fourth capacitor, and the fourteenth resistor is connected to the third Between the collector of the switch tube and the base of the fourth switch tube, one end of the fifteenth resistor is connected to the base of the fourth switch tube, and the other end is grounded; one end of the fourth capacitor is The collector of the fourth switch is connected and the other end is grounded.
The speaker driving signal abnormality detecting circuit according to claim 9, wherein the first switching tube, the second switching tube and the third switching tube are PNP type transistors; and the fourth switching tube is an NPN type triode.
A speaker protection circuit includes a power amplifier, a first speaker, and a second speaker, wherein the power amplifier has a first channel and a second channel, the first channel has a first positive output terminal and a first negative output terminal, and a second The channel has a second positive output terminal and a second negative output terminal, and the power amplifier is electrically connected to the first speaker through the first positive output terminal and the first negative output terminal; the power amplifier passes through the second positive electrode The output end and the second negative output are electrically connected to the second speaker; wherein the speaker protection circuit further comprises a control circuit and the speaker drive signal abnormality detecting circuit according to any one of claims 1-10, The first positive output end and the second positive output end of the power amplifier are connected to the first detecting circuit of the speaker driving signal abnormality detecting circuit; the first negative output end and the second negative output end of the power amplifier are connected to the speaker driving a second detecting circuit of the signal abnormality detecting circuit; an output end of the output circuit of the speaker driving signal abnormality detecting circuit is connected to the control circuit; The speaker driving signal abnormality detecting circuit detects a voltage signal outputted by the power amplifier to the speaker, and outputs a voltage abnormal signal to the control circuit when the output voltage of any one of the power amplifiers is higher than a preset voltage value, the control circuit The power amplifier output is cut off or the output of the power amplifier is adjusted according to the voltage abnormality signal.