Audio plug-in detection circuit and audio playback device

Abstract

The present invention discloses an audio plug-in detection circuit and an audio playback device. The audio plug-in detection circuit comprises: a control module, a switch module, a first audio terminal and a second audio terminal; wherein the control module is respectively connected to the switch module, the first audio terminal and the second audio terminal, and the switch module is connected to an external device. The present invention sends an insertion control signal to the switch module when the control module detects that the first audio terminal and the second audio terminal are short-circuited, and the switch module outputs an audio insertion signal to the external device according to the insertion control signal, thereby achieving the purpose of realizing audio plug-in detection without using a chip, thereby solving the technical problem that the audio plug-in detection requires the use of a chip, resulting in excessively high costs.

Description

Technical Field

[0001] The present invention relates to the technical field of audio control, and in particular to an audio plug-in detection circuit and an audio playback device. Background Art

[0002] With the improvement of living standards, more and more audio playback devices and technologies are applied to actual production and life, bringing great convenience to people, such as the currently popular voice conferencing, remote voice chat and large-scale broadcast conferences.

[0003] At present, in order to detect the plugging and unplugging of audio cables, two insertion detection terminals are usually added to the audio cable socket (refer to Figure 1 ), inside the audio line socket, two detection terminals and two audio signals constitute two normally closed mechanical switches respectively. The insertion and removal of the audio line plug changes the on-off state of the two mechanical switches inside the socket. One of the two detection terminals is connected in series with a smaller resistor (for example, 1KΩ) R1 to ground, and the other is connected in series with a resistor R2 (for example, 10K-100KΩ) much larger than R1 to pull up to a power supply of a certain logic level. A small resistor R3 (for example, 1K) is connected in parallel between the two audio lines. Then, the logic level reflecting the plug-in and unplugging state of the audio line can be obtained at the terminal connected with the pull-up resistor R2, thereby achieving the purpose of detecting the plug-in and unplugging state of the audio line.

[0004] However, the above-mentioned plug-in detection method requires application software logic to ensure the sequence of audio line plug-in and audio playback, so a coding and decoding chip needs to be provided in the playback device, resulting in excessively high cost of the audio playback device.

[0005] The above contents are only used to assist in understanding the technical solution of the present invention and do not constitute an admission that the above contents are prior art. Summary of the invention

[0006] The main purpose of the present invention is to provide an audio plug-in detection circuit and an audio playback device, aiming to solve the technical problem in the prior art that audio plug-in detection requires the use of chips resulting in excessively high costs.

[0007] To achieve the above object, the present invention provides an audio plug-in detection circuit, the audio plug-in detection circuit comprising: a control module, a switch module, a first audio terminal and a second audio terminal;

[0008] Wherein, the control module is connected to the switch module, the first audio terminal and the second audio terminal respectively, and the switch module is connected to an external device;

[0009] The control module is used to output an insertion control signal to the switch module when the first audio terminal and the second audio terminal are short-circuited;

[0010] The switch module is used to output an audio insertion signal to the external device when receiving the insertion control signal, so that the external device confirms that the audio line is inserted.

[0011] Optionally, the switch module includes: a first MOS tube and a first resistor;

[0012] Among them, the gate of the first MOS tube is connected to the control module, the drain of the first MOS tube is respectively connected to the first end of the first resistor and the input end of the external device, the source of the first MOS tube is grounded, and the second end of the first resistor is connected to the power supply end.

[0013] Optionally, the control module includes: second to third resistors, first to fourth diodes, a second MOS tube and a first capacitor;

[0014] Among them, the first end of the first capacitor, the first end of the second resistor and the power supply end are connected, the second end of the first capacitor is grounded, the second end of the second resistor is connected to the anode of the first diode and the anode of the second diode, the cathode of the first diode is connected to the first audio end and the gate of the second MOS tube, the cathode of the second diode is connected to the second audio end, the drain of the second MOS tube is connected to the second end of the third resistor and the anode of the third diode, the source of the second MOS tube is grounded, the first end of the third resistor is connected to the power supply end, the second end of the second resistor is also connected to the anode of the fourth diode, the cathode of the fourth diode is connected to the cathode of the third diode, and the cathode of the third diode is connected to the switch module.

[0015] Optionally, the control module further includes: a fourth resistor and a fifth resistor;

[0016] Among them, the first end of the fourth resistor is connected to the power supply end, the second end of the fourth resistor is connected to the first audio end, the first end of the fifth resistor is connected to the cathode of the second diode, and the second end of the fifth resistor is grounded.

[0017] Optionally, the audio plug-in detection circuit further includes: a filtering module;

[0018] The filtering module includes: a first filtering unit and a second filtering unit;

[0019] Wherein, the first filtering unit is connected to the control module and the first audio terminal respectively, and the second filtering unit is connected to the control module and the second audio terminal respectively;

[0020] The first filtering unit is used to filter out the audio interference signal coupled to the first audio terminal;

[0021] The second filtering unit is used to filter out the audio interference signal coupled to the second audio terminal.

[0022] Optionally, the filtering module further includes: a third filtering unit;

[0023] Wherein, the third filtering unit is connected to the control module and the switch module respectively;

[0024] The third filtering unit is used to filter out the low-frequency audio interference signal received by the control module.

[0025] Optionally, the first filtering unit includes: a sixth resistor and a second capacitor;

[0026] The first end of the sixth resistor is connected to the first audio terminal, the second end of the sixth resistor is connected to the second end of the fourth resistor and the first end of the second capacitor, and the second end of the second capacitor is grounded.

[0027] Optionally, the second filtering unit includes: a seventh resistor and a third capacitor;

[0028] The first end of the seventh resistor is connected to the second audio terminal, the second end of the seventh resistor is connected to the first end of the fifth resistor and the first end of the third capacitor, and the second end of the third capacitor is grounded.

[0029] Optionally, the third filtering unit includes: an eighth resistor and a fourth capacitor;

[0030] Among them, the first end of the fourth capacitor, the first end of the eighth resistor, the cathode of the third diode, the cathode of the fourth diode and the input end of the switch module are connected together, the second end of the fourth capacitor is grounded, and the second end of the fourth resistor is grounded.

[0031] In addition, to achieve the above-mentioned purpose, the present invention further provides an audio playback device, which includes the audio plug-in detection circuit as described above.

[0032] The present invention provides an audio plug-in detection circuit, which includes: a control module, a switch module, a first audio terminal and a second audio terminal; wherein the control module is respectively connected to the switch module, the first audio terminal and the second audio terminal, and the switch module is connected to an external device; the control module is used to output an insertion control signal to the switch module when the first audio terminal and the second audio terminal are short-circuited; the switch module is used to output an audio insertion signal to the external device when receiving the insertion control signal, so that the external device confirms that the audio line is inserted. The present invention sends an insertion control signal to the switch module when the control module detects that the first audio terminal and the second audio terminal are short-circuited, and the switch module outputs an audio insertion signal to the external device according to the insertion control signal, thereby achieving the purpose of realizing audio plug-in detection without using a chip, thereby solving the technical problem that the audio plug-in detection requires the use of a chip, resulting in excessively high costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0034] Figure 1 It is an audio plug-in detection circuit diagram in the prior art;

[0035] Figure 2 This is a structural schematic diagram of a first embodiment of an audio plug-in detection circuit proposed by the present invention;

[0036] Figure 3 This is a structural schematic diagram of an audio line socket of an audio player device of the present invention;

[0037] Figure 4 An audio plug-in detection circuit diagram of a second embodiment of the audio plug-in detection circuit provided by the present invention;

[0038] Figure 5 This is an audio plug-in detection circuit diagram of the third embodiment of the audio plug-in detection circuit proposed by the present invention.

[0039] Description of Figure Numbers:

[0040] Label name Label name R1-R8 The first to eighth resistors C1-C4 The first to fourth capacitors D1-D4 The first to fourth diodes Q1 The first MOS tube Q2 The second MOS tube VDD IO power supply terminal GND Ground terminal DET1 First audio terminal DET2 Second audio port 10 Control Module 20 Switch module 31 The first filter unit 32 The second filter unit 33 The third filter unit SPL Left channel terminal SPR Right channel terminal MIC Microphone terminal SPK_OUTP Audio positive output terminal SPK_OUTN Audio negative output terminal Ra Resistor R Resistor b Rc Resistor c Rd Resistor d

[0041] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0042] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0045] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0046] Reference Figure 2 , Figure 2 This is a schematic structural diagram of the first embodiment of the audio plug-in detection circuit proposed by the present invention.

[0047] based on Figure 2 A first embodiment of an audio plug-in detection circuit of the present invention is provided.

[0048] In this embodiment, the audio plug detection circuit includes: a control module 10, a switch module 20, a first audio terminal DET1 and a second audio terminal DET2;

[0049] The control module 10 is connected to the switch module 20, the first audio terminal DET1 and the second audio terminal DET2 respectively, and the switch module 20 is connected to an external device.

[0050] It should be noted that, refer to Figure 3 , Figure 3It is a schematic diagram of the structure of the audio line socket of the audio playback device in the present invention. In the present embodiment, the ground terminal GND, the microphone terminal MIC, the left channel terminal SPL and the right channel terminal SPR are only the names of the external connection terminals of the audio line socket, and do not represent the actual output or input signal names. The first audio terminal DET1 is connected to the ground terminal GND of the audio line socket, the second audio terminal DET2 is connected to the microphone terminal MIC, the left channel terminal SPL is connected to the audio positive output terminal SPK_OUTP of the audio power amplifier chip, and the right channel terminal SPR is connected to the audio negative output terminal of the audio power amplifier chip. When there is no audio line inserted in the audio line socket, the ground terminal GND and the microphone terminal MIC are suspended to the outside, so the first audio terminal DET1 and the second audio terminal DET2 are also suspended to the outside; when a 2-segment audio line is inserted in the audio line socket, Figure 3 It can be seen that the ground terminal GND, the microphone terminal MIC and the right channel terminal SPR of the audio cable socket are short-circuited together through the second section of the audio cable. At this time, the first audio terminal DET1, the second audio terminal DET2 and the audio negative output terminal SPK_OUTN are short-circuited together.

[0051] It can be understood that when the first audio terminal DET1 and the second audio terminal DET2 are short-circuited together, it indicates that an audio line is inserted into the audio line socket. In this embodiment, when the control module 10 detects that the first audio terminal DET1 and the second audio terminal DET2 are short-circuited together, a high-level insertion control signal is sent to the switch module 20. When the switch module 20 receives the high-level insertion control signal, it outputs a low-level audio insertion signal to the external device, so that the external device confirms the insertion of the audio line.

[0052] The present embodiment provides an audio plug-in detection circuit, the audio plug-in detection circuit comprising: a control module, a switch module, a first audio terminal and a second audio terminal; wherein the control module is respectively connected to the switch module, the first audio terminal and the second audio terminal, and the switch module is connected to an external device; the control module is used to output an insertion control signal to the switch module when the first audio terminal and the second audio terminal are short-circuited; the switch module is used to output an audio insertion signal to the external device when receiving the insertion control signal, so that the external device confirms that the audio line is inserted. In the present embodiment, the control module sends an insertion control signal to the switch module when detecting that the first audio terminal and the second audio terminal are short-circuited, and the switch module outputs an audio insertion signal to the external device according to the insertion control signal, thereby achieving the purpose of realizing audio plug-in detection without using a chip, thereby solving the technical problem that the audio plug-in detection requires the use of a chip, which results in excessively high costs.

[0053] Reference Figure 4 , Figure 4This is a diagram of an audio plug-in detection circuit according to a second embodiment of the audio plug-in detection circuit provided by the present invention.

[0054] based on Figure 4 A second embodiment of the audio plug-in detection circuit of the present invention is provided.

[0055] In this embodiment, the switch module 20 includes: a first MOS tube Q1 and a first resistor R1;

[0056] Among them, the gate of the first MOS tube Q1 is connected to the control module 10, the drain of the first MOS tube Q1 is respectively connected to the first end of the first resistor R1 and the input end of the external device, the source of the first MOS tube Q1 is grounded, and the second end of the first resistor R1 is connected to the power supply end VDD.

[0057] It should be noted that the first MOS tube Q1 can be an N-type MOS tube or a P-type MOS tube. If the first MOS tube Q1 is a PMOS tube, the source of the first MOS tube Q1 is connected to the power supply terminal VDD, the drain is connected to one end of the first resistor R1, and the other end of the first resistor R1 is grounded; a current limiting resistor of about 1K needs to be connected in series between the drain of the first MOS tube Q1 and the external device to prevent the circuit from being burned out due to excessive current at a high level. In this embodiment, the first MOS tube Q1 is described by taking an N-type MOS tube as an example. When the gate of the MOS tube has a high level input, that is, the voltage between the gate and the source reaches the turn-on voltage of the MOS tube, the MOS tube is turned on. When the gate of the MOS tube has a low level input or no voltage input, that is, the voltage between the gate and the source does not reach the turn-on voltage of the MOS tube, the MOS tube is turned off. When the MOS tube is turned on, the first resistor R1 is grounded to protect the circuit; when the MOS tube is turned off, the first resistor R1 acts as a voltage reducer so that the high-level voltage signal output by the switch module 20 to the external device meets the requirements of the external device.

[0058] It can be understood that when the gate of the first MOS tube Q1 receives the high-level audio insertion control signal sent by the control module 10, the first MOS tube Q1 is turned on, the first resistor R1 is grounded through the first MOS tube, and the first end of the first resistor R1 is at a low level at this time. The external device confirms that the audio line is inserted through the low-level signal at the first end of the first resistor R1.

[0059] It should be understood that when the control module 10 connected to the gate of the first MOS tube Q1 has no voltage signal output or outputs a low-level voltage signal, the first MOS tube Q1 is not turned on. At this time, the first end of the first resistor R1 is at a high level, and the external device confirms that no audio line is inserted through the high-level signal at the first end of the first resistor R1.

[0060] In this embodiment, the control module 10 includes: second to third resistors, first to fourth diodes, a second MOS tube and a first capacitor;

[0061] Among them, the first end of the first capacitor C1 and the first end of the second resistor R2 are connected to the power supply terminal VDD, the second end of the first capacitor C1 is grounded, the second end of the second resistor R2 is connected to the anode of the first diode D1 and the anode of the second diode D2, the cathode of the first diode D1 is connected to the first audio terminal DET1 and the gate of the second MOS transistor Q2, the cathode of the second diode D2 is connected to the second audio terminal DET2, the drain of the second MOS transistor Q2 is connected to the second end of the third resistor R3 and the anode of the third diode D3, the source of the second MOS transistor Q2 is grounded, the first end of the third resistor R3 is connected to the power supply terminal VDD, the second end of the second resistor R2 is also connected to the anode of the fourth diode D4, the cathode of the fourth diode D4 is connected to the cathode of the third diode D3, and the cathode of the third diode D3 is connected to the switch module 20.

[0062] It should be noted that, in this embodiment, when the audio player plays audio, the audio negative output terminal SPK_OUTN of the audio amplifier chip outputs a voltage signal higher than the logic high level. At this time, if an audio line is inserted into the audio line socket, the first audio terminal DET1, the second audio terminal DET2 and the audio negative output terminal SPK_OUTN are short-circuited together, so the first audio terminal DET1 and the second audio terminal DET2 have a voltage signal input higher than the logic high level. The first capacitor C1 is a voltage stabilizing capacitor, which ensures that the first end of the second resistor R2 and the first end of the third resistor R3 have a stable high level input.

[0063] It can be understood that in this embodiment, when the first audio terminal DET1 and the second audio terminal DET2 are short-circuited and a voltage signal higher than the logic high level is input (i.e., the audio device is playing audio), the first diode D1 and the second diode D2 are both not conducting, a voltage signal higher than the logic high level is input to the gate of the second MOS tube Q2, the source and drain of the second MOS tube Q2 are conducting, the drain of the MOS tube is grounded, the voltage level is zero, the anode of the third diode D3 is connected to the drain of the MOS tube, and therefore the third diode D3 is not conducting. The anode of the fourth diode D4 is connected to the second end of the second resistor R2, the second resistor R2 is connected to the power supply end, the second end of the second resistor R2 is at a high level, therefore the fourth diode D4 is conducting, the cathode of the fourth diode D4 is at a high level at this time, and at this time the audio insertion control signal output by the control module 10 to the switch module 20 is a high level signal at the cathode of the fourth diode.

[0064] It should be understood that the high-level signal outputted from the cathode of the fourth diode D4 is an audio insertion control signal when the audio device plays audio.

[0065] In this embodiment, the control module further includes: a fourth resistor R4 and a fifth resistor R5;

[0066] Among them, the first end of the fourth resistor R4 is connected to the power supply terminal VDD, the second end of the fourth resistor R4 is connected to the first audio terminal DET1, the first end of the fifth resistor R5 is connected to the cathode of the second diode D2, and the second end of the fifth resistor R5 is grounded.

[0067] It should be noted that, in the present embodiment, the first audio terminal DET1 and the second audio terminal DET2 are short-circuited, and when there is no voltage signal higher than the logic high level input (i.e., the audio device does not play audio), the anode voltage of the first diode D1 and the second diode D2 are both greater than the cathode voltage, i.e., the first diode D1 and the second diode D2 are both in a conducting state, and at this time, the second resistor R2 and the fourth resistor R4 are equivalent to being connected in parallel, and the second end of the second resistor R2 and the second end of the fourth resistor R4 can both be regarded as being connected to the first end of the fifth resistor R5, and since the second end of the fifth resistor R5 is grounded, and the fifth resistor R5 is much smaller than the second resistor R2 and the fourth resistor R4, the fourth resistor R5 is connected to the ground. The voltages at the second end of the resistor R4 and the second end of the second resistor R2 are pulled down to a low level voltage by the fifth resistor R5, and the anode of the fourth diode D4 is connected to the second end of the second resistor R2, so the fourth diode D4 is not turned on; at this time, the gate input voltage of the second MOS tube Q2 is the second end voltage of the fourth resistor R4, so the second MOS tube Q2 is also not turned on, and at this time, the first end of the third resistor R3 is connected to the power supply, the second end of the third resistor R3 is connected to the anode of the third diode D3, the third diode D3 is turned on, and the cathode of the third diode D3 is high level. At this time, the audio insertion control signal output by the control module 10 to the switch module 20 is a high level signal of the cathode of the third diode.

[0068] It should be understood that the high-level signal outputted from the cathode of the third diode D3 is an audio insertion control signal when the audio device does not play audio.

[0069] It should also be noted that when no audio cable is inserted into the audio cable socket, no matter whether the audio device plays or not plays audio, the first audio terminal DET1 and the second audio terminal DET2 have no signal input. Therefore, when no audio cable is inserted into the audio cable socket, there is only one logic control mode, which does not distinguish between audio playback and no audio playback.

[0070] It can also be understood that, in the present embodiment, when the first audio terminal DET1 and the second audio terminal DET2 are both suspended (i.e., when no audio cable is inserted into the audio cable socket), the cathode potential of the first diode D1 is pulled up to the same potential as the IO power supply terminal VDD through the fourth resistor R4, and the anode potential of the first diode D1 is pulled down to a lower potential by the second resistor R2 and the fifth resistor R5, so the first diode D1 is cut off and the second diode D2 is turned on. The gate of the second MOS tube Q2 is connected to the power supply terminal VDD through the fourth resistor R4. At this time, the gate of the second MOS tube Q2 has a high level input, and the source and drain of the second MOS tube Q2 are connected. Since the source of the second MOS tube Q2 is grounded, the drain level of the second MOS tube Q2 is zero, and the anode level of the third diode D3 connected to the drain of the second MOS tube Q2 is also zero. At this time, the third diode D3 is not turned on; since the second diode D2 is turned on, the second end of the second resistor R2 can be regarded as connected to the first end of the fifth resistor R5. Since the resistance value of the fifth resistor R5 is much smaller than the resistance value of the second resistor R2, and the fifth resistor R5 is The second end of R5 is grounded, causing the voltage at the second end of the second resistor R2 to be pulled down to a low level voltage; the anode of the fourth diode D4 is connected to the second end of the second resistor R2, and since the cathode of the fourth diode D4 is connected to the cathode of the third diode D3, and the voltage level is zero, the fourth diode D4 is turned on, and the voltage at the cathode of the fourth diode D4 is a low level voltage. At this time, the signal output by the control module 10 to the switch module 20 is a low level voltage signal at the cathode of the fourth diode D4. After receiving the low level voltage signal, the switch module 20 outputs a high level voltage signal to the external device, so that the external device confirms that no audio cable is inserted.

[0071] In this embodiment, when audio is playing and an audio line is inserted, the high-level signal outputted by the cathode of the fourth diode controls the switch module to output a low-level audio insertion signal to the external device, so that the external device confirms that the audio line is inserted; when there is no audio playing and the audio line is inserted, the high-level signal outputted by the cathode of the third diode controls the switch module to output a low-level audio insertion signal to the external device, so that the external device confirms that the audio line is inserted; when there is no audio line inserted, the low-level voltage signal at the cathode of the fourth diode controls the switch module to output a high-level no-audio insertion signal to the external device, so that the external device confirms that there is no audio line inserted, thereby realizing audio line insertion detection when audio is playing or not playing.

[0072] Reference Figure 5 , Figure 5 This is an audio plug-in detection circuit diagram of the third embodiment of the audio plug-in detection circuit proposed by the present invention.

[0073] based on Figure 5 , a third embodiment of the audio plug and unplug detection circuit of the present invention is proposed.

[0074] In this embodiment, the audio plug-in detection circuit further includes: a filtering module;

[0075] The filtering module includes: a first filtering unit 31 and a second filtering unit 32;

[0076] The first filtering unit 31 is connected to the control module 10 and the first audio terminal DET1 respectively, and the second filtering unit 32 is connected to the control module 10 and the second audio terminal DET2 respectively.

[0077] It should be noted that when no audio cable is plugged in and audio is played, since the first audio terminal DET1 and the second audio terminal DET2 are suspended and due to line settings, the first audio terminal DET1 and the second audio terminal DET2 may be coupled to a part of the audio interference signal.

[0078] It can be understood that, in this embodiment, the first filtering unit 31 is used to filter out the audio interference signal coupled to the first audio terminal DET1, and the second filtering unit 32 is used to filter out the audio interference signal coupled to the second audio terminal DET2.

[0079] In this embodiment, the filtering module further includes: a third filtering unit 33;

[0080] The third filtering unit 33 is connected to the control module 10 and the switch module 20 respectively.

[0081] It should be noted that, in this embodiment, the analog audio amplifier will output a low-frequency audio signal, which will interfere with the insertion control signal output by the control module 10; the third filtering unit 33 is used to filter out the low-frequency audio interference signal received by the control module 10.

[0082] In this embodiment, the first filtering unit 31 includes: a sixth resistor R6 and a second capacitor C2;

[0083] The first end of the sixth resistor R6 is connected to the first audio terminal DET1, the second end of the sixth resistor R6 is connected to the second end of the first resistor R1 and the first end of the second capacitor C2, and the second end of the second capacitor C2 is grounded.

[0084] In this embodiment, the second filtering unit 32 includes: a seventh resistor R7 and a third capacitor C3;

[0085] The first end of the seventh resistor R7 is connected to the second audio terminal DET2, the second end of the seventh resistor R7 is connected to the first end of the fifth resistor R5 and the first end of the third capacitor C3, and the second end of the third capacitor C3 is grounded.

[0086] In this embodiment, the third filtering unit 33 includes: an eighth resistor R8 and a fourth capacitor C4;

[0087] Among them, the first end of the fourth capacitor C4, the first end of the eighth resistor R8, the cathode of the third diode D3, the cathode of the fourth diode D4 and the input end of the switch module 20 are connected together, the second end of the fourth capacitor C4 is grounded, and the second end of the eighth resistor R8 is grounded.

[0088] It can be understood that in this embodiment, the resistance of the sixth resistor R6 and the seventh resistor R7 is much smaller than the resistance of the fifth resistor R5, and much larger than the DC resistance of the speaker, so that the voltage drop at the first audio terminal DET1 and the second audio terminal DET2 is very small and can be ignored. The eighth resistor R8 can be a very large resistor (for example, 2M ohms); the second to third capacitors are all filter capacitors and can be selected according to actual conditions.

[0089] This embodiment filters out external audio interference through a filtering module, thereby ensuring the stability and accuracy of audio insertion detection.

[0090] In addition, to achieve the above-mentioned purpose, the present invention further provides an audio playback device, wherein the audio playback device comprises the audio plug-in detection circuit as described above.

[0091] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An audio plug-in detection circuit, characterized in that: The audio plug-in detection circuit comprises: a control module, a switch module, a first audio terminal and a second audio terminal; Wherein, the control module is connected to the switch module, the first audio terminal and the second audio terminal respectively, and the switch module is connected to an external device; The control module is used to output an insertion control signal to the switch module when the first audio terminal and the second audio terminal are short-circuited; The switch module is used to output an audio insertion signal to the external device when receiving the insertion control signal, so that the external device confirms the insertion of the audio line; The audio plug-in detection circuit further includes: a filtering module; The filtering module includes: a first filtering unit and a second filtering unit; Wherein, the first filtering unit is connected to the control module and the first audio terminal respectively, and the second filtering unit is connected to the control module and the second audio terminal respectively; The first filtering unit is used to filter out the audio interference signal coupled to the first audio terminal; The second filtering unit is used to filter out the audio interference signal coupled to the second audio terminal; The filtering module further includes: a third filtering unit; Wherein, the third filtering unit is connected to the control module and the switch module respectively; The third filtering unit is used to filter out the low-frequency audio interference signal received by the control module.

2. The audio plug detection circuit according to claim 1, characterized in that: The switch module includes: a first MOS tube and a first resistor; Among them, the gate of the first MOS tube is connected to the control module, the drain of the first MOS tube is respectively connected to the first end of the first resistor and the input end of the external device, the source of the first MOS tube is grounded, and the second end of the first resistor is connected to the power supply end.

3. The audio plug detection circuit as claimed in claim 2, characterized in that: The control module includes: second to third resistors, first to fourth diodes, a second MOS tube and a first capacitor; Among them, the first end of the first capacitor, the first end of the second resistor and the power supply end are connected, the second end of the first capacitor is grounded, the second end of the second resistor is connected to the anode of the first diode and the anode of the second diode, the cathode of the first diode is connected to the first audio end and the gate of the second MOS tube, the cathode of the second diode is connected to the second audio end, the drain of the second MOS tube is connected to the second end of the third resistor and the anode of the third diode, the source of the second MOS tube is grounded, the first end of the third resistor is connected to the power supply end, the second end of the second resistor is also connected to the anode of the fourth diode, the cathode of the fourth diode is connected to the cathode of the third diode, and the cathode of the third diode is connected to the switch module.

4. The audio plug detection circuit as claimed in claim 3, characterized in that: The control module further includes: a fourth resistor and a fifth resistor; Among them, the first end of the fourth resistor is connected to the power supply end, the second end of the fourth resistor is connected to the first audio end, the first end of the fifth resistor is connected to the cathode of the second diode, and the second end of the fifth resistor is grounded.

5. The audio plug detection circuit as claimed in claim 4, characterized in that: The first filtering unit includes: a sixth resistor and a second capacitor; The first end of the sixth resistor is connected to the first audio terminal, the second end of the sixth resistor is connected to the second end of the fourth resistor and the first end of the second capacitor, and the second end of the second capacitor is grounded.

6. The audio plug-in detection circuit as claimed in claim 5, characterized in that: The second filtering unit includes: a seventh resistor and a third capacitor; The first end of the seventh resistor is connected to the second audio terminal, the second end of the seventh resistor is connected to the first end of the fifth resistor and the first end of the third capacitor, and the second end of the third capacitor is grounded.

7. The audio plug detection circuit according to claim 6, characterized in that: The third filtering unit includes: an eighth resistor and a fourth capacitor; Among them, the first end of the fourth capacitor, the first end of the eighth resistor, the cathode of the third diode, the cathode of the fourth diode and the input end of the switch module are connected together, the second end of the fourth capacitor is grounded, and the second end of the eighth resistor is grounded.

8. An audio playback device, characterized in that: The audio playback device comprises the audio plug-in detection circuit according to any one of claims 1-7.

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