CN111757202B

CN111757202B - Earphone recognition device, sound playing device and earphone recognition method

Info

Publication number: CN111757202B
Application number: CN202010573777.2A
Authority: CN
Inventors: 张华敬; 刘晃助
Original assignee: Universal Global Technology Kunshan Co Ltd
Current assignee: Universal Global Technology Kunshan Co Ltd
Priority date: 2020-06-22
Filing date: 2020-06-22
Publication date: 2022-05-27
Anticipated expiration: 2040-06-22
Also published as: CN111757202A

Abstract

The utility model provides an earphone identification device, is suitable for discerning a plug-in earphone and is a stereo earphone or a tone earphone, and this earphone identification device includes a treater, an discernment comparator circuit and a switching circuit. The processor receives a trigger signal when the earphone is inserted into an earphone jack and outputs a starting signal according to the trigger signal. The identification comparison circuit is electrically connected with the earphone jack and the processor, judges an earphone level signal of a preset sound pin in the earphone jack when receiving the starting signal, and correspondingly outputs a first switching signal or a second switching signal according to a judgment result. The switching circuit is electrically connected with the identification comparison circuit and the earphone jack; when the identification comparison circuit judges that the earphone level signal belongs to a first level represented by the single-tone earphone, a first switching signal is output to the switching circuit; when the identification comparison circuit judges that the earphone level signal belongs to a second level represented by the stereo earphone, a second switching signal is output to the switching circuit.

Description

Earphone recognition device, sound playing device and earphone recognition method

Technical Field

The invention discloses an identification device, and particularly relates to an earphone identification device.

Background

There is still no common PTT headset specification in the market, and developers need to define pins of a headset plug or define keys in a software manner to determine stereo, single tone or push-to-talk (PTT) headsets, which results in poor compatibility.

Disclosure of Invention

The invention aims to provide a hardware logic judgment circuit solution under the common stereo earphone structure of a handheld device, and aims to identify a stereo earphone or a single-tone earphone when an earphone plug is inserted. In view of the above, according to an embodiment of the present invention, an earphone recognition apparatus for recognizing an inserted earphone as a stereo earphone or a mono earphone is provided, which includes a processor, a recognition comparing circuit and a switching circuit. The processor receives a trigger signal when the earphone is inserted into an earphone jack and outputs a starting signal according to the trigger signal. The identification comparison circuit is electrically connected with the earphone jack and the processor, judges an earphone level signal of a preset sound pin in the earphone jack when receiving the starting signal, and correspondingly outputs a first switching signal or a second switching signal according to a judgment result. The switching circuit is electrically connected with the identification comparison circuit and the earphone jack.

Particularly, when the identification comparison circuit judges that the earphone level signal belongs to a first level represented by a single-tone earphone, a first switching signal is output to the switching circuit, so that the switching circuit provides the earphone level signal of a preset sound pin in the earphone jack to the processor according to the first switching signal, and the processor determines that the earphone is inserted into the single-tone earphone.

Particularly, when the identification comparison circuit judges that the earphone level signal belongs to a second level represented by the stereo earphone, a second switching signal is output to the switching circuit, so that the switching circuit enables a preset sound pin in the earphone jack to be communicated with a transmission channel circuit corresponding to the stereo earphone according to the second switching signal.

According to another embodiment of the present invention, a sound playing apparatus is provided, which has the earphone recognition apparatus as described in the present disclosure, wherein the processor controls the sound playing apparatus to execute a mono-tone playing mode when the processor receives the earphone level signal of the predetermined sound pin and the earphone level signal belongs to a first level, and the processor controls the sound playing apparatus to execute a stereo-tone playing mode when the processor receives the earphone level signal of the predetermined sound pin and the earphone level signal belongs to a second level.

According to another embodiment of the present invention, there is provided a method for recognizing a headphone, which is adapted to a headphone recognition device to recognize whether an inserted headphone is a stereo headphone or a mono headphone, the method including: when an earphone is inserted into an earphone jack, a processor in the earphone identification device receives a trigger signal and outputs a starting signal to an identification comparison circuit in the earphone identification device according to the trigger signal; when the identification comparison circuit receives the starting signal, the identification comparison circuit judges an earphone level signal of a preset sound pin in the earphone jack and correspondingly outputs a first switching signal or a second switching signal to a switching circuit in the earphone identification device according to the judgment result.

When the identification comparison circuit judges that the earphone level signal belongs to a first level represented by a single-tone earphone, a first switching signal is output to the switching circuit, so that the switching circuit provides the earphone level signal of a preset sound pin in the earphone jack to the processor according to the first switching signal, and the processor determines that the earphone is inserted into the earphone as the single-tone earphone; when the identification comparison circuit judges that the earphone level signal belongs to a second level represented by the stereo earphone, a second switching signal is output to the switching circuit, so that the switching circuit communicates a preset sound pin in the earphone jack with a transmission channel circuit corresponding to the stereo earphone according to the second switching signal.

The invention uses hardware circuit design to complete different earphone judgment, the earphone identification device has built-in single-tone earphone or stereo earphone judgment function, does not need to match corresponding earphone jack aiming at the different functions of the two, only needs one earphone identification device on the mainboard to realize the identification of the single-tone earphone or the stereo earphone, and can save the time course and the cost of system development.

For a further understanding of the techniques, methods and technical effects of the invention to achieve the stated objectives, it is believed that the objects, features and characteristics of the invention will be more fully understood from the following detailed description of the invention and the accompanying drawings, which are provided for purposes of illustration and description and are not intended to be limiting.

Drawings

Fig. 1 presents a block diagram of a headset identification device according to an embodiment of the present invention;

fig. 2A presents a stereo headphone wiring schematic;

FIG. 2B is a schematic diagram of a single-tone earphone connection according to an embodiment of the present invention;

fig. 3 is a block diagram of an identification comparison circuit in the earphone identification device according to an embodiment of the present invention;

fig. 4 is a block diagram of a logic operation circuit in the earphone recognition device according to an embodiment of the present invention;

fig. 5 is a flow chart of a method for recognizing a headset according to an embodiment of the present invention;

fig. 6 shows a partial circuit diagram of an earphone recognition apparatus according to an embodiment of the present invention;

fig. 7 shows a partial circuit diagram of an earphone recognition apparatus according to an embodiment of the present invention.

Detailed Description

The following description is provided by way of specific embodiments of the present invention, and those skilled in the art will understand the advantages and effects of the present invention from the contents provided in the present specification. The invention is capable of other and different embodiments and its several details are capable of modification and various other changes, which can be made in various details within the specification and without departing from the spirit and scope of the invention. The drawings of the present invention are for illustrative purposes only and are not intended to be drawn to scale. The following embodiments will further explain the related art of the present invention in detail, but the contents are not provided to limit the scope of the present invention.

It will be understood that, although the terms first, second, third, etc. may be used herein to describe various components or signals, these components or signals should not be limited by these terms. These terms are used primarily to distinguish one element from another element or from one signal to another signal. In addition, the term "or" as used herein should be taken to include any one or combination of more of the associated listed items as the case may be.

Referring to fig. 1, a block diagram of an earphone recognition device 10 according to an embodiment of the present invention is shown. The earphone recognition device 10 can be integrated into various earphone-insertable sound playing devices, such as a notebook computer, a mobile device, a mobile phone, a tablet computer, etc. with a built-in sound playing device. As shown, the earphone recognition device 10 includes a switching circuit 103, a recognition comparing circuit 105 and a processor 107. The earphone recognition device 10 is adapted to recognize whether a plug-in earphone 2 is a stereo earphone or a mono earphone.

Please refer to fig. 2A and 2B, which show two plug-in headphone plugs matched with the headphone jack and the connection schematic diagram thereof.

Fig. 2A presents a stereo headphone wiring schematic. As shown, the stereo headphone plug 2a with four rings may be a CTIA interface standard compliant stereo headphone, for example: 3.5mm earphone. Stereo earphone utensil four-section type headphone plug from top to bottom includes in proper order: a left channel zone 21, a right channel zone 22, a ground zone 23, and a microphone zone (MIC) 24. The right half of the rendering stereo headphone of fig. 2A can be connected in series by a resistor between the left and right channel region pins, and the left and right channel region pins are not grounded, the smaller the resistance of the resistor is, the larger the wattage that can be pushed.

Fig. 2B is a schematic diagram of a single tone earphone connection according to an embodiment of the present invention. As shown in fig. 2B, the single-tone earphone plug 2B having four rings may be a 3.5mm earphone, a four-segment single-tone earphone. Compared to stereo headphones, mono headphones have only mono (i.e., one of the left and right channels).

Push To Talk (PTT) headsets may be implemented with a single-tone headset. Compared to a stereo headphone jack, a PTT headphone jack has only a single channel zone (such as the left channel zone); the other channel zone, such as the right channel zone, is not used to transmit audio source signals, but is designed to transmit headphone level signals of a preset sound pin to perform the PTT function.

In detail, the PTT earphone has a four-segment single-tone earphone plug 2b, which sequentially comprises: a left channel zone 21 ', a PTT sense zone 22', a ground zone 23 ', and a microphone zone 24'. The source of the PTT headset is typically left monophonic. The right half of fig. 2B presents the wiring of the different pins of the PTT headset. As shown in the figure, a left channel pin and a PTT sense pin (corresponding to a right channel pin of the stereo headphone) of the PTT headphone are respectively connected in series with resistors with different resistance values, and the resistance value of the resistor connected in series with the left channel pin is smaller than the resistance value of the resistor connected in series with the right channel pin. Preferably, the resistance value of the resistor connected in series with the pin of the right sound channel region is 1000 ohms, and the resistance value of the resistor connected in series with the pin of the left sound channel region is between 16 and 64 ohms.

Therefore, the stereo headphone plug 2a and the mono headphone plug 2b correspond to the pin lines of the two types of headphones, respectively. The pin of the right channel area and the pin of the PTT sense area respectively present different impedance characteristics. The invention utilizes the level difference of the earphone level signal reflected by the impedance characteristic, thereby distinguishing different types of earphone plugs.

For example, when the stereo headphone plug 2a is plugged into a headphone jack, since the right channel zone pin corresponding to the right channel zone 22 of the stereo headphone plug 2a is not grounded, the right channel zone pin will exhibit a null level; when the single-tone earphone plug 2b is plugged into the earphone jack, the pin of the PTT sense region corresponding to the PTT sense region 22' of the single-tone earphone plug 2b is connected in series with a resistor, and the pin of the PTT sense region will show a low level. The invention utilizes the difference between the idle connection level and the low level to distinguish different types of earphone plugs, namely, the earphone plugs belong to a stereo earphone plug 2a or a single-tone earphone plug 2 b.

However, in other embodiments, the sound source and sense source (sense) of the PTT headset may be configured in a left-right manner, i.e. the right channel is used as the sound source of the PTT headset, and the left channel is used as the sense source of the PTT headset, which is not limited in the present invention.

Referring again to fig. 1, in one embodiment, the monophonic earphone is a push-to-talk (PTT) earphone, and the sound source of the monophonic earphone is output only from the left channel and the right channel is used as the PTT perceived source (sense).

The second area from top to bottom for stereo headphone jacks is the right channel area and the second area from top to bottom for mono headphone jacks is the PTT sense source (sense) area.

In one embodiment, the predetermined sound pin in the headphone jack 101 corresponds to the right channel region of a stereo headphone or the PTT sense region of a mono headphone.

When the earphone 2 is inserted into an earphone jack 101, the processor 107 receives a trigger signal sent by the earphone jack 101 and indicating that the earphone is inserted into the earphone jack 101, and outputs a start signal to the identification comparison circuit 105 according to the trigger signal. It is noted that the trigger signal is no longer present if the plug-in earphone 2 is removed from the earphone jack 101.

The identification comparison circuit 105 is electrically connected to the headphone jack 101 and the processor 107, and when receiving the start signal, the identification comparison circuit 105 determines that an headphone level signal from a preset sound pin in the headphone jack 101 is at a low level (L), or is idle-connected or floating-connected (NC), and outputs a first switching signal or a second switching signal according to the determination result.

The switching circuit 103 is electrically connected to the identification and comparison circuit 105 and the headphone jack 101, and can be used to realize compatibility of a single-tone headphone or a stereo headphone.

Specifically, when the identification and comparison circuit 105 determines that the headphone level signal belongs to a first level represented by a single-tone headphone, it outputs a first switching signal to the switching circuit 103, so that the switching circuit 103 provides the headphone level signal of the preset sound pin in the headphone jack 101 to the processor 107 according to the first switching signal, so that the processor 107 can identify that the inserted headphone 2 is a single-tone headphone.

Specifically, when the identification comparing circuit 105 determines that the headphone level signal is at a second level represented by the stereo headphones, the second switching signal is output to the switching circuit 103, so that the switching circuit 103 connects the predetermined sound pin in the headphone jack 101 to a transmission channel line 3 corresponding to the stereo headphones according to the second switching signal.

Referring to fig. 1 and fig. 3, fig. 3 is a block diagram of an identification comparison circuit in an earphone identification device according to an embodiment of the present invention. The identification comparison circuit 105 includes a signal isolation circuit 1051 and a logic operation circuit 1053.

The signal isolation circuit 1051 outputs a first level when receiving a ground level provided by the right channel zone pin of the single-tone headphone with respect to the default sound pin after receiving the start signal sent by the processor 107, and outputs a second level when receiving a ground level provided by the right channel zone pin of the stereo headphone with respect to the preset sound pin.

The logic operation circuit 1053 is electrically connected to the signal isolation circuit 1051, the logic operation circuit 1053 outputs a first switching signal to the switching circuit 103 when receiving a first level, and the logic operation circuit 1053 outputs a second switching signal to the switching circuit 103 when receiving a second level. Preferably, the first level represented by the mono headset is low, the second level represented by the stereo headset is high, and the enabling signal is a pulse signal.

In one embodiment, the identification comparison circuit 105 further includes a reset circuit 1055 electrically connected to the signal isolation circuit 1051.

The reset circuit 1055 may be used to generate a reset signal. The reset circuit 1055 functions to reset the determination behavior of the ear speaker identification device 10 when the plug-in ear speaker 2 is removed from the ear speaker jack 101. When the reset circuit 1055 does not receive the trigger signal from the headphone jack 101, it outputs a reset signal to the signal isolation circuit 1051, so that the signal isolation circuit 1051 outputs the default second level. When the reset circuit 1055 receives the trigger signal from the headphone jack 101, it stops outputting the reset signal.

In one embodiment, the switching circuit 103 includes a switch, which is used to switch off or on the signal flow. The switch provides the processor 107 with the headphone level signal of the preset sound pin in the headphone jack 101 when receiving the first switching signal, and communicates the preset sound pin in the headphone jack 101 with the transmission channel line 3 corresponding to the stereo headphone when receiving the second switching signal.

Referring to fig. 3 and 4, fig. 4 is a block diagram of a logic operation circuit in the earphone recognition device according to an embodiment of the present invention. The logic operation circuit 1053 includes an inverter circuit 10531 and a logic or gate 10533.

The inverter 10531 is used to convert the first level into a first inverted level and convert the second level into a second inverted level. The or gate 10533 is electrically connected to the inverter 10531, the logic operation circuit 1053 outputs a first switching signal when receiving a first inversion level, and the logic operation circuit 1053 outputs a second switching signal when receiving a second inversion level.

When the headphone plug is plugged into the headphone jack 101, the two-input or gate receives the first level or the second level from the signal isolation circuit 1051 and outputs the first switching signal or the second switching signal to the switching circuit 103.

Referring to fig. 1 to 4, an audio playing device may include any one of the earphone recognition devices shown in fig. 1 to 4.

When the processor 107 receives the headphone level signal of the preset sound pin and the headphone level signal belongs to the first level, the processor 107 controls the sound playing apparatus to execute a single-tone playing mode.

When the processor 107 receives the earphone level signal of the preset sound pin and the earphone level signal belongs to the second level, the processor 107 controls the sound playing device to execute a stereo playing mode.

Referring to fig. 1, fig. 2 and fig. 5, fig. 5 is a flowchart illustrating an earphone recognition method according to an embodiment of the present invention. The method is suitable for the earphone recognition device 10 to recognize whether the inserted earphone 2 belongs to the stereo earphone plug 2a or the single-tone earphone plug 2b, and comprises the following steps:

in step S501, a sound playing device with the headphone jack 101 is activated.

In step S503, when a plug-in earphone 2 is plugged into an earphone jack 101, the earphone recognition device 10 determines whether the earphone jack 101 has the plug-in earphone 2; if yes, go to step S505, the processor 107 in the earphone recognition device 10 receives the trigger signal; if not, the process returns to step S503.

In step S507, the processor 107 outputs an activation signal to the identification comparison circuit 105 in the earphone identification device 10 according to the trigger signal.

In step S509, the identification comparing circuit 105 determines a headphone level signal of a predetermined sound pin in the headphone jack 101 when receiving the start signal. The identification comparing circuit 105 correspondingly outputs a first switching signal or a second switching signal to a switching circuit 103 of the earphone identification device 10 according to the determination result (step S510 or step S511).

In step S512, when the identification and comparison circuit 105 determines that the headphone level signal belongs to a first level represented by a single-tone headphone, it outputs a first switching signal to the switching circuit 103, so that the switching circuit 103 provides the headphone level signal of the preset sound pin in the headphone jack 101 to the processor 107 according to the first switching signal, so that the processor 107 recognizes that the headphone 2 is plugged into the single-tone headphone plug 2b and belongs to the single-tone headphone.

In step S513, when the identification comparing circuit 105 determines that the headphone level signal belongs to a second level represented by the stereo headphones, the identification comparing circuit outputs a second switching signal to the switching circuit 103, so that the switching circuit 103 connects the preset sound pin in the headphone jack 101 to a transmission channel line 3 corresponding to the stereo headphones according to the second switching signal. In other words, the plug-in headphone 2 has a stereo headphone plug 2a and belongs to a stereo headphone.

As shown in step S515, the reset circuit 1055 determines whether the headphone jack 101 is not inserted with the headphone 2; if yes, go to step S517, the reset circuit 1055 outputs a reset signal; if not, the process returns to step S515.

Referring to table 1, fig. 1-4, fig. 6 and fig. 7 together, fig. 6 and 7 present a partial circuit diagram of a push-to-talk headset and stereo headset identification device according to an embodiment of the present invention. Fig. 6 highlights the headphone jack 101 and the switching circuit 103 in the headphone identification device, and fig. 7 highlights the identification comparison circuit 105 in the headphone identification device. The headset identification device includes a headset jack 101 (including CTIA J701), a switching circuit 103 (including an analog switch U705), an identification comparison circuit 105, and a processor 107. Fig. 6 and 7 together present a complete circuit diagram of a push-to-talk headset and stereo headset identification device according to an embodiment of the present invention.

The headphone jack 101 includes a Connector (Connector) for connecting a voice jack flexible printed circuit (Audio jack FPC) and a switching circuit 103.

The switching circuit 103 may be coupled to the transmission channel line 3 through an NO pin of an Analog switch (Analog switch) and coupled to the processor 107 through an NC pin thereof.

The normally open voltage (for example, VREG _ L13A _1P8) generated by the audio player with earphone recognition device after being turned on can be used as the voltage source of the recognition comparison circuit 105. MIC _ BIAS and VREG _ L13A _1P8 serve as voltage sources for the chips in the earphone recognition device or as high levels of the signal bus. AMIC2_ IN _ P is supplied with a voltage by MIC _ BIAS on the Audio codec. However, the voltage source of the present invention is not limited thereto.

Table 1 shows a truth table of the signal states generated by the PTT earphone and stereo earphone in the earphone recognition device before, after, or after the earphone is inserted.

The circuit structure of the earphone recognition device of the invention is that the earphone sound source conforming to the CTIA interface standard is only output by the left sound channel, and the right sound channel is used as the PTT sense source (sense). When the stereo headphone and the PTT headphone are inserted into and removed from the headphone identification device, signals are generated, and the signal states show a truth table of levels such as high level (H)/low level (L)/idle connection (NC) and the like as shown in table 1.

TABLE 1

IN detail, the relevant signals generated when the earphone plug is inserted into or removed from the earphone jack shown IN the truth table include the headphone _ DET signal (i.e., the trigger signal disclosed above), the PRESET signal (i.e., the reset signal disclosed above), the R _ AUTO _ DET signal (i.e., the earphone level signal disclosed above), the AUTO _ DET signal (i.e., the first level or the second level disclosed above), the AUTO _ DET _ N signal (i.e., the first inverted level or the second inverted level disclosed above), the PTT _ IN signal (i.e., the first switching signal or the second switching signal disclosed above), the PTT _ DET signal (i.e., the switching circuit output signal disclosed above), and the HPH _ R signal (i.e., the output signal of the switching circuit disclosed above via the transmission channel line 3).

Referring to fig. 1 again, it can be determined whether the inserted earphone 2 is a PTT earphone according to the difference between the levels of the related signals shown in table 1. The headphone identification means 10 does not detect the PTT state until the plug of the headphone 2 is inserted into the headphone jack 101.

Preferably, a change in the receive-input-port Headset _ DET signal at the headphone jack 101 triggers the identification comparison circuit 105 to enable PTT function detection and generate the level of the associated signal.

Preferably, after the earphone 2 is inserted into the earphone jack 101, the elastic sheet on the earphone jack 101 is grounded to change the input port HEADSET _ DET signal from high level to low level to start the PTT function detection. The processor 107 then provides a pulse signal to activate the identification comparison circuit 105 and the switching circuit 103, and after logical decision, the final AUTO _ DET signal level can be reported back to the processor 107 via the switching circuit 103 to confirm whether the inserted headset 2 is a PTT headset.

Preferably, when the earphone 2 is plugged into the earphone jack 101, the elastic piece on the earphone jack 101 is grounded, and the processor 107 receives the input port headdet signal. When the input port heiset _ DET signal assumes a high to low level, the processor 107 outputs an enable signal to trigger the identification comparison circuit 105 to detect the type of inserted HEADSET 2.

The identification comparison circuit 105 determines that a headphone level signal from a predetermined sound pin IN the headphone jack 101 exhibits a low level (L)/no connection, floating connection (NC) (e.g., R _ AUTO _ DET signal), and outputs a first switching signal (e.g., a PTT _ IN high level signal) or a second switching signal (e.g., a PTT _ IN low level signal) according to the determination result.

When the identification comparison circuit 105 determines that the earphone level signal (e.g., R _ AUTO _ DET signal) belongs to a first level (e.g., AUTO _ DET low level signal) represented by the single-tone earphone, it outputs a first switching signal to the switching circuit 103.

When the identification comparison circuit 105 determines that the headphone level signal is at a second level (e.g., AUTO _ DET high level signal) belonging to the stereo headphones, it outputs a second switching signal to the switching circuit 103.

Preferably, when the switching circuit 103 determines that the input port HEADSET _ DET signal is at a low level and the PTT _ IN signal is at a high level according to the input port HEADSET _ DET signal and the PTT _ IN signal of the headphone jack 101, the switching circuit 103 outputs an output port PTT _ DET signal to the processor 107. For example, the switching circuit 103 may send a PTT _ DET signal to the processor 107 through the GPIO _47 pin of the analog switch.

Preferably, the identification comparing circuit 105 determines that the input port HEADSET _ DET signal is at a low level and the PTT _ IN signal is at a low level by the switching circuit 103 according to the HEADSET _ DET signal and the PTT _ IN signal of the headphone jack 101, and the switching circuit 103 connects the preset sound pin of the headphone jack 101 to the transmission channel line 3 corresponding to the stereo headphones and outputs an HPH _ R signal.

The identification comparison circuit 105 includes a signal isolation circuit 1051, a logic operation circuit 1053 (including a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) Q702 and a two-input or gate U704), and a reset circuit 1055 (including a MOSFET Q701). The signal isolation circuit 1051 is electrically connected to the switching circuit 103.

The signal isolation circuit 1051 includes a D-Type Flip-Flop (D-Type Flip-Flop) U707. The D-type flip-flop has an input, an output and a frequency input.

The logic operation circuit 1053 includes an inverter circuit 10531(MOSFET Q702) and a logic or gate 10533 (two-input or gate U704). The logic or gate 10533 is electrically connected to the heiset _ DETECT pin of CTIA J701, and the HPH _ REF pin of CTIA J701 is grounded. For a two-input or gate, the two-input or gate output is high as long as at least one of the two inputs is high. The logic operation circuit 1053 is electrically connected to the signal isolation circuit 1051 and the switching circuit 103, respectively.

Preferably, the inverter circuit 10531 includes a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) for converting the first level to a first inverted level (e.g., AUTO _ DET _ N high signal) and converting the second level to a second inverted level (e.g., AUTO _ DET _ N low signal).

Preferably, the GPIO _56 pin of the D-type flip-flop of the signal isolation circuit 1051 receives a pulse signal from the processor 107 occupying a 10ms rising edge to prevent errors due to noise and to increase the amount of data processed through the pipeline, and the D-type flip-flop outputs an AUTO _ DET signal.

Preferably, the reset circuit is configured to generate a reset signal (e.g., a reset low signal). The reset circuit 1055 stops outputting the reset signal when receiving the trigger signal from the headphone jack 101.

Preferably, the identification comparing circuit 105 determines that the analog switch of the switching circuit 103 is at a low level and the PTT _ IN signal is at a low level according to the HEADSET _ DET signal and the PTT _ IN low level signal at the input port of the headphone jack 101, and the analog switch connects a preset sound pin of the headphone jack 101 to a transmission Channel (COM) line 3 corresponding to stereo headphones and outputs an HPH _ R signal.

Preferably, if the stereo headphone plug 2a is inserted, the identification comparison circuit 105 determines that the input port HEADSET _ DET signal is at a low level and the PTT _ IN signal is at a low level according to the input port HEADSET _ DET signal and the PTT _ IN signal of the headphone jack 101 by the switching circuit 103, and the switching circuit 103 connects the preset sound pin IN the headphone jack 101 to the transmission channel line 3 corresponding to the stereo headphones.

Preferably, when the earphone 2 is plugged into the earphone jack 101, and if the earphone 2 has a single-tone earphone plug 2b, the switching circuit 103 determines that the input port HEADSET _ DET signal is at a low level and the PTT _ IN signal is at a high level, the switching circuit 103 outputs the output port PTT _ DET signal to the processor 107, so that the processor 107 recognizes that the plugged earphone is a single-tone earphone (i.e., PTT earphone).

[ possible technical effects of the embodiment ]

In summary, the earphone recognition device of the present invention utilizes the circuit connection structure among the earphone jack, the switching circuit, the recognition comparison circuit and the processor to design the judgment modes of different earphones by hardware circuits. The earphone identification device is internally provided with the judging functions of a single tone earphone (PTT earphone) and a stereo earphone, so that the identification of the PTT earphone or the stereo earphone can be realized, the compatibility of the PTT earphone or the stereo earphone can be realized, and the system development time and cost can be saved.

It should be finally noted that while in the foregoing specification, the present inventive concept has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the present inventive concept as defined by the appended claims.

Claims

1. An earphone identification apparatus adapted to identify an inserted earphone as either a stereo earphone or a mono earphone, comprising:

the processor receives a trigger signal when the inserted earphone is inserted into an earphone jack and outputs a starting signal according to the trigger signal;

the identification comparison circuit is electrically connected with the earphone jack and the processor, judges an earphone level signal of a preset sound pin in the earphone jack when receiving the starting signal, and correspondingly outputs a first switching signal or a second switching signal according to a judgment result; and

the switching circuit is electrically connected with the identification comparison circuit and the earphone jack;

wherein the identification comparison circuit outputs the first switching signal to the switching circuit when determining that the headphone level signal belongs to a first level represented by the single-tone headphone, so that the switching circuit provides the headphone level signal of the preset sound pin in the headphone jack to the processor according to the first switching signal, so that the processor can identify the inserted headphone as the single-tone headphone;

when the identification comparison circuit judges that the earphone level signal belongs to a second level represented by the stereo earphone, the identification comparison circuit outputs the second switching signal to the switching circuit, so that the switching circuit enables the preset sound pin in the earphone jack to be communicated with a transmission channel circuit corresponding to the stereo earphone according to the second switching signal;

wherein the identification comparison circuit comprises:

a signal isolation circuit, configured to output the first level when the preset sound pin receives a ground level provided by a right channel zone pin of the mono headset after receiving the start signal, and output the second level when the preset sound pin receives a ground level provided by a right channel zone pin of the stereo headset;

the reset circuit is electrically connected with the signal isolation circuit and used for generating a reset signal, and when the inserted earphone is pulled out of the earphone jack, the reset circuit enables the judgment behavior of the earphone identification device to be reset; and

and the logic operation circuit is electrically connected with the signal isolation circuit, outputs the first switching signal to the switching circuit when receiving the first level, and outputs the second switching signal to the switching circuit when receiving the second level.

2. The apparatus of claim 1, wherein the single-tone earphone is a push-to-talk earphone, the left channel pin and the right channel pin of the single-tone earphone are respectively connected in series with resistors having different resistance values, and the resistance value of the resistor connected in series with the left channel pin is smaller than the resistance value of the resistor connected in series with the right channel pin.

3. The apparatus of claim 2, wherein the predetermined sound pin in the headphone jack corresponds to a right channel zone pin of the stereo headphone or corresponds to a right channel zone pin of the mono headphone.

4. The apparatus according to claim 1, wherein the logic operation circuit comprises:

an inverter circuit for converting the first level to a first inverted level and the second level to a second inverted level; and

the logic operation circuit outputs the first switching signal when receiving the first inversion level, and outputs the second switching signal when receiving the second inversion level.

5. The apparatus of claim 1, wherein the signal isolation circuit comprises a D-type flip-flop, the first level is low, the second level is high, and the enable signal is a pulse signal.

6. The device as claimed in claim 5, wherein the reset circuit outputs the reset signal to the D-type flip-flop when the trigger signal from the headphone jack is not received, so that the D-type flip-flop outputs the preset second level; and the reset circuit stops outputting the reset signal when receiving the trigger signal.

7. The apparatus of claim 6, wherein the switching circuit comprises a switch for providing the headphone level signal of the predetermined sound pin in the headphone jack to the processor when receiving the first switching signal, and for communicating the predetermined sound pin in the headphone jack with the transmission channel line corresponding to the stereo headphone when receiving the second switching signal.

8. An audio playback device having the apparatus for recognizing earphone level according to one of claims 1 to 7, wherein the processor controls the audio playback device to operate in a mono playback mode when the earphone level signal of the predetermined audio pin is received and the earphone level signal belongs to the first level, and controls the audio playback device to operate in a stereo playback mode when the earphone level signal of the predetermined audio pin is received and the earphone level signal belongs to the second level.

9. A method for identifying a headphone, the method being adapted to be used by a headphone identification apparatus to identify an inserted headphone as a stereo headphone or a mono headphone, the method comprising:

when an earphone is inserted into an earphone jack, a processor in the earphone identification device receives a trigger signal and outputs a starting signal to an identification comparison circuit in the earphone identification device according to the trigger signal;

when receiving the starting signal, the identification comparison circuit judges an earphone level signal of a preset sound pin in the earphone jack and correspondingly outputs a first switching signal or a second switching signal to a switching circuit in the earphone identification device according to a judgment result;

when the identification comparison circuit determines that the headphone level signal belongs to a first level represented by the single-tone headphone, the identification comparison circuit outputs the first switching signal to the switching circuit, so that the switching circuit provides the headphone level signal of the preset sound pin in the headphone jack to the processor according to the first switching signal, so that the processor can identify the inserted headphone as the single-tone headphone; and

wherein the identification comparison circuit comprises:

the logic operation circuit is electrically connected with the signal isolation circuit, outputs the first switching signal to the switching circuit when receiving the first level, and outputs the second switching signal to the switching circuit when receiving the second level.

10. The method of claim 9, wherein the single-tone earphone is a push-to-talk earphone, the left channel region pin and the right channel region pin of the single-tone earphone are respectively connected in series with resistors with different resistance values, and the resistance value of the resistor connected in series with the left channel region pin is smaller than the resistance value of the resistor connected in series with the right channel region pin.

11. The method of claim 10, wherein the predetermined sound pin in the headphone jack corresponds to a right channel zone pin of the stereo headphone or corresponds to a right channel zone pin of the mono headphone.

12. The method of claim 9, wherein the logic operation circuit comprises:

13. The method as claimed in claim 9, wherein the signal isolation circuit comprises a D-type flip-flop, the first level is a low level, the second level is a high level, and the enable signal is a pulse signal.

14. The headset identification method of claim 13, wherein the reset circuit outputs the reset signal to the D-type flip-flop when the trigger signal from the headset jack is not received, so that the D-type flip-flop outputs the preset second level;

and the reset circuit stops outputting the reset signal when receiving the trigger signal.

15. The method of claim 14, wherein the switching circuit comprises a switch for providing the headphone level signal of the predetermined sound pin in the headphone jack to the processor when receiving the first switching signal, and for communicating the predetermined sound pin in the headphone jack with the transmission channel line corresponding to the stereo headphone when receiving the second switching signal.