Wireless earphone circuit with wired function and wireless headsetTechnical field
The utility model belongs to audio output apparatus technical field, specifically, being to be related to a kind of circuit of wireless headsetDesign.
Background technology
Wireless headset is a kind of reception audio signal source in the form of radio wave（Host）The audio data of transmitting, and locateAnalog audio signal is managed into, the audio-frequence player device of loud speaker sounding is pushed.Wireless headset compared to traditional wired earphone,Good portability is widely applied in daily life.For example, when people are driving, move and be inconvenient to receive callsWhen, it can be received calls using wireless headset, by the both hands for liberating people so that drive safer, movement is more freely.
But wireless headset is in use, is frequently encountered the feelings that wireless headset can not be used by not enough power supplyCondition, or because of audio signal source（Host）Do not have wireless transmitting function and causes what wireless headset paired can not use to askTopic.To solve this problem it is necessary to realize the access in radio function of audio signal on wireless headset, make it both can conductWireless headset uses, and can be used as wired earphone.
In order to realize wired function on wireless headset, need to configure earphone socket on wireless headset, for externalEarphone cable, and then audio signal source is received by earphone cable（Host）The audio signal of output.Due to existing wireless headset,The audio signal of wireless audio processing chip output is differential signal, therefore what is configured in earphone is differential output circuit.And lead toThe audio signal for crossing earphone cable transmission is single-ended signal, therefore in order to enable wireless headset to export single-ended signal, is needed in nothingSingle-end output circuit is configured in line earphone.Based on this, existing design scheme is to add difference in wireless headset to turn single-ended electricityThe differential signal that wireless audio processing chip exports is converted into single-ended signal, is sent to loud speaker sounding by road.This circuit is setMeter can not only increase hardware cost, but also compared to Single-end output circuit, since differential output circuit has very common-mode signalTherefore strong inhibiting effect, strong antijamming capability, the output power of loud speaker can be lost using existing design schemeThe advantages of wireless headset script due difference output.
Invention content
The purpose of this utility model is to provide a kind of wireless earphone circuits of the wired function of band, not only can be in wireless earThe function of wired earphone is realized on machine, and under radio function, audio signal can still be pushed in the form of differential signalLoud speaker, the advantages of to remain existing wireless headset original difference output.
In order to solve the above technical problems, the utility model is achieved using following technical scheme：
The utility model is in one aspect, it is proposed that a kind of wireless earphone circuit of the wired function of band, including loud speaker, nothingLine audio processing modules, earphone socket and switch module；The loud speaker include for receive difference audio signal anode andCathode；The wireless audio processing module receives wireless audio signal, and is processed into difference audio signal, is sent to described raise one's voiceDevice；The earphone socket includes audio transmission pin, and the audio transmission pin connects the anode of the loud speaker；The switchModule connects the cathode of the loud speaker, controls when the cathode of the loud speaker is inserted into headset plug in earphone socket and is grounded.
In order to realize that accurately break-make controls to the switch module, the utility model is gone back in the wireless earphone circuitIt is provided with plug-pull detecting circuit, connects the earphone socket, is used for plug shape of the test earphone plug in the earphone socketState, and the switch module break-make is controlled according to the plug state.
Further, the switch module includes switch ways and control terminal, and the switch ways are connected to described raise one's voiceBetween the cathode and ground of device, the control terminal connects the plug-pull detecting circuit.
A kind of preferred circuit as the plug-pull detecting circuit designs, including DC power supply, the pull-up electricity being sequentially connected in seriesResistance and contact；Draw with the audio transmission in earphone socket when the contact is inserted into the earphone socket without headset plugFoot contact connection, and have in the earphone socket and detached with the audio transmission pin when headset plug insertion, the switchThe control terminal of module connects the contact by conducting wire, and the switch module break-make is controlled according to the level state on contact.
Further, the switch module can select the positive voltage letter that conduction voltage drop is more than in the difference audio signalThe switch element of number amplitude and voltage magnitude less than the DC power supply.
Preferably, the switch element preferably uses N-channel MOS pipe, the drain electrode of the metal-oxide-semiconductor to connect the loud speakerCathode, the source electrode ground connection of the metal-oxide-semiconductor, grid connect the contact by conducting wire.
The case where being Wireless stereo earphone for wireless headset, the loud speaker includes two, and respectively L channel is raised one's voiceDevice and right channel loudspeaker, the corresponding L channel difference audio signal and right channel difference for receiving the output of wireless audio processing moduleAudio signal；The earphone socket is four-wire system earphone socket, including left channel audio transmission pin and right audio channel transmissionPin connects one to one with positive and right channel loudspeaker the anode of left channel loudspeaker respectively；The metal-oxide-semiconductor includes twoIt is a, it is connect when the cathode of control left channel loudspeaker and the cathode of right channel loudspeaker are inserted into headset plug in earphone socket respectivelyGround；It is connect with the left channel audio transmission pin in earphone socket when the contact is inserted into the earphone socket without headset plugTouch connection.
In order to make the wireless audio processing module in the wired mode can be out of service in wireless headset work, with trueIt protects the single-ended audio signal accessed by earphone socket can reliably play, the utility model is in the wireless audio processing moduleUpper setting can control the Enable Pin of its enabled operation, and the Enable Pin is connected to the plug-pull detecting circuit, passes through plugDetection circuit controls out of service when the wireless audio processing module has a headset plug insertion in earphone socket.
Preferably, the Enable Pin of the wireless audio processing module connects the contact by conducting wire.
The utility model is on the other hand, it is also proposed that a kind of wireless headset, including loud speaker, wireless audio handle mouldBlock, earphone socket and switch module；The loud speaker includes the anode and cathode for receiving difference audio signal；It is described wirelessAudio processing modules receive wireless audio signal, and are processed into difference audio signal, are sent to the loud speaker；The earphone is insertedSeat includes audio transmission pin, and the audio transmission pin connects the anode of the loud speaker；Described in the switch module connectionThe cathode of loud speaker is controlled when the cathode of the loud speaker is inserted into headset plug in earphone socket and is grounded.
Compared with prior art, the advantages of the utility model and good effect is：The wireless headset of the utility model passes throughThe cathode for controlling its loud speaker receives the negative voltage difference audio letter of wireless audio processing module output under wireless operating modeNumber, and be grounded under wired operating mode, to realize the switching of wireless and wired function, difference and single-ended signal, circuitIt is simple in structure, of low cost, the advantages of not only having remained the difference output of radio function, but also realize the defeated of wired single-ended signalGo out, improve the overall performance of wireless headset, improves the usage experience of user.
After the detailed description of the utility model embodiment is read in conjunction with the figure, other features and advantages of the utility modelIt will become clearer.
Description of the drawings
Fig. 1 is a kind of circuit theory of embodiment of the wireless earphone circuit for the wired function of band that the utility model is proposedBlock diagram；
Fig. 2 is a kind of physical circuit schematic diagram of embodiment of wireless earphone circuit shown in FIG. 1.
Specific implementation mode
Specific embodiment of the present utility model is described in more detail below in conjunction with the accompanying drawings.
As described in Figure 1, the wireless headset of the present embodiment includes wireless audio processing module, earphone socket, loud speaker, switchThe chief components such as module.Wherein, wireless audio processing module is used for and audio signal source（Host）Wireless communication receives soundFrequency source signal（Host）The wireless audio signal sent out（Usually audio data forms）, and will receive at wireless audio signalManage into difference audio signal（Analog electrical signal form）, it is transmitted to the positive P and cathode N of loud speaker, and then by loud speakerElectro-acoustic transducer device make a sound.Earphone socket is used for peripheral earphone line, passes through earphone cable and audio signal source（Host）HaveLine connects, to receive audio signal source（Host）The single-ended audio signal of offer.In order to enable loud speaker to play single-ended audioThe audio transmission pin that single-ended audio signal is used for transmission in earphone socket is connected to the anode of loud speaker by signal, the present embodimentP, and in the cathode N connecting valve modules of loud speaker.When the switch module has headset plug insertion in earphone socket, controlThe cathode N ground connection of the loud speaker completes wireless headset to realize loud speaker normally receiving and playing to single-ended audio signalWired function.And when being inserted into without headset plug in earphone socket, the switch module control the cathode N of the loud speaker withGround disconnects, it is ensured that loud speaker can normally receive the audio signal of difference form, that is, receives the output of wireless audio processing moduleDifference audio signal, to realize the radio function of earphone.
It is controlled to carry out accurately break-make to the switch module, to realize wirelessly and wired function, difference and single-endedThe accurate switching of signal, the present embodiment are additionally provided with plug-pull detecting circuit in the wireless headset, as shown in Figure 1, forPlug state of the test earphone plug in earphone socket, and then corresponding detection signal is formed according to plug state, control is openedIt closes module to be switched on or off, realizes and the ground connection of the cathode N of loud speaker is controlled.
In a period of in order to there is headset plug insertion in earphone socket, wireless headset can automatically switch to wired workPattern controls the wireless audio processing module inside earphone and is automatically stopped operation, then ensures the audio letter that loud speaker receivesNumber be only single-ended audio signal, it is ensured that sound accurately plays, and the present embodiment preferably uses in the wireless headset with wired functionWireless audio processing module with enabled control function carries out circuit design, the detection signal formed using plug-pull detecting circuitEnabled control is carried out to the wireless audio processing module, wireless audio processing module is made to make when earphone is operated in wireless modeIt can run, receive audio signal source（Host）The wireless audio signal sent out, and it is converted into difference audio signal, push loud speakerSounding；And when earphone is operated in wireline mode, control wireless audio processing module stop it is enabled, into off position, intoAnd ensure that the audio signal for being sent to loud speaker is only single-ended audio signal, realize wired function of wireless headset.
Below by taking wireless headset is three-dimensional earphone as an example, physical circuit design and its work to the wireless headset of the present embodimentIt is described in detail as principle.
As shown in Fig. 2, the Wireless stereo earphone of the present embodiment includes two loud speakers SPKR_L, SPKR_R, it is respectively used toPlay left channel audio signal and right channel audio signal.When earphone is operated in wireless mode, wireless audio processing module willThe wireless audio signal received is processed into L channel difference audio signal SPKR_LP, SPKR_LN and right channel difference audio letterNumber SPKR_RP, SPKR_RN, the corresponding positive P and cathode N and right channel loudspeaker for being transmitted to left channel loudspeaker SPKR_LThe positive P and cathode N of SPKR_R plays stereo sound by left and right sound channels loud speaker SPKR_L, SPKR_R.Since difference is believedNumber it is common-mode signal, there is very strong AF panel effect, therefore the output quality of sound can be improved, and loud speaker can be promotedThe output power of SPKR_L, SPKR_R.
Four-wire system earphone socket J1 is set on the Wireless stereo earphone of the present embodiment, including left channel audio transmits pinL, right audio channel transmission pin R, microphone pin MIC and grounding pin GND.Wherein, left channel audio transmission pin L is used forL channel single-ended audio signal is transmitted, the cathode N of the positive P of connection L channel earphone SPKR_L, L channel earphone SPKR_L are logicalCross the switch ways ground connection of switch module Q2；Right audio channel transmission pin R is used for transmission right channel single-ended audio signal, connectsThe cathode N of the positive P of right-channel ear SPKR_R, right-channel ear SPKR_R are connect by the switch ways of another switch module Q1Ground；Microphone pin MIC transmits microphone signal MIC_SIGNAL, connects the microphone on earphone, picks up user speech；Ground connectionPin GND connections earphone systematically, realize head circuit and host circuit totally.One gold is set in earphone socket J1Belong to contact DE, when designing the metal contact piece DE and being inserted into without headset plug in earphone socket J1, with the sound in earphone socket J1Keep pouring in defeated pin（By taking left channel audio transmission pin L as an example）Contact connection；And there is headset plug insertion in earphone socket J1When, the extruding using headset plug to audio transmission pin shrapnel, and audio transmission pin is made to be detached with the metal contact piece DE.The metal contact piece DE is connected to the control terminal of two switch modules Q1, Q2 by conducting wire, and is connected by pull-up resistor R1The conduction voltage drop of DC power supply VCC in head circuit, configuration switch module Q1, Q2 are more than defeated by wireless audio processing moduleThe amplitude of positive voltage signal SPKR_LP, SPKR_RP in the difference audio signal gone out, and the voltage amplitude less than DC power supply VCCValue when to there is headset plug insertion in earphone socket J1, since metal contact piece DE is suspended, and makes two switch modulesThe voltage of the control terminal of Q1, Q2 is equal to the voltage magnitude of DC power supply VCC.At this point, two switch modules Q1, Q2 control its switchAccess is closed, and by the cathode N ground connection of left and right sound channels loud speaker SPKR_L, SPKR_R, only passes through left and right sound channels loud speaker SPKR_L, the positive P of SPKR_R receives left and right sound channels single-ended audio signal, meets loud speaker SPKR_L, SPKR_R and believes single-ended audioNumber reception requirement, realize wired function of wireless headset.Meanwhile the Enable Pin EN of wireless audio processing module is passed through into conducting wireIt is connected to the metal contact piece DE, and it is enabled to configure wireless audio processing module low level.When having headset plug in earphone socket J1When insertion, DC power supply VCC is applied to the Enable Pin EN of wireless audio processing module by pull-up resistor R1, at this time Enable Pin ENFor the invalid state of high level, wireless audio processing module is out of service, the output of indifference multi-voice frequency signal.
When being inserted into without headset plug in earphone socket J1, metal contact piece DE transmits pin L and a left side by left channel audioThe positive P of channel loudspeaker SPKR_L is connected to.When wireless audio processing module not output difference audio signal, metal contact piece DEOn voltage be low level, wireless audio processing module and is controlled because the voltage on its Enable Pin EN is low level effective statusThe enabled operation of wireless audio processing module processed, even if wireless audio processing module output difference audio signal, as long as configuration is wirelessThe positive voltage that the Enable Pin EN of audio processing modules is more than to entering the high level needed for invalid state in difference audio signal, i.e.,It can maintain the enabled operating status of wireless audio processing module.At the same time, two switch modules Q1, Q2 are due to its control terminal electricityIt forces down and enters off state in its conduction voltage drop, thus can ensure that left and right sound channels loud speaker SPKR_L, SPKR_R normally connectAstigmat multi-voice frequency signal, realizes the radio function of earphone.
As a kind of preferred design of the present embodiment, described switch module Q1, Q2 can select triode, metal-oxide-semiconductorOr silicon-controlled equal switch elements.The present embodiment is illustrated for selecting two N-channel MOS pipes.As shown in Fig. 2, by MOSThe drain electrode of pipe Q1 is connected to the cathode N of right channel loudspeaker SPKR_R, source electrode ground connection, and grid connects metal contact piece by conducting wireDE, by controlling metal-oxide-semiconductor Q1 conductings, to control the cathode N ground connection of right channel loudspeaker SPKR_R.Similarly, by the leakage of metal-oxide-semiconductor Q2Pole is connected to the cathode N of left channel loudspeaker SPKR_L, source electrode ground connection, and grid connects metal contact piece DE by conducting wire, passes through controlMetal-oxide-semiconductor Q2 conductings processed, to control the cathode N ground connection of left channel loudspeaker SPKR_L.
The wireless headset of the present embodiment realizes wired and wireless, difference and single-ended letter by using simple switch elementNumber switching, it is of low cost, not only remained the difference output advantage of radio function, but also realize the output of single-ended signal, improveProperties of product.
Certainly, the above description is not intended to limit the present invention, and the utility model is also not limited to the example above,The variations, modifications, additions or substitutions that those skilled in the art are made in the essential scope of the utility model,It should also belong to the protection scope of the utility model.