WO2012031481A1 - Adaptive circuit of earphone interface - Google Patents
Adaptive circuit of earphone interface Download PDFInfo
- Publication number
- WO2012031481A1 WO2012031481A1 PCT/CN2011/073199 CN2011073199W WO2012031481A1 WO 2012031481 A1 WO2012031481 A1 WO 2012031481A1 CN 2011073199 W CN2011073199 W CN 2011073199W WO 2012031481 A1 WO2012031481 A1 WO 2012031481A1
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- WIPO (PCT)
- Prior art keywords
- pin
- earphone
- electronic device
- bias
- resistor
- Prior art date
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Classifications
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R29/00—Monitoring arrangements; Testing arrangements
- H04R29/004—Monitoring arrangements; Testing arrangements for microphones
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R1/00—Details of transducers, loudspeakers or microphones
- H04R1/10—Earpieces; Attachments therefor ; Earphones; Monophonic headphones
- H04R1/1041—Mechanical or electronic switches, or control elements
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R2420/00—Details of connection covered by H04R, not provided for in its groups
- H04R2420/01—Input selection or mixing for amplifiers or loudspeakers
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R2420/00—Details of connection covered by H04R, not provided for in its groups
- H04R2420/03—Connection circuits to selectively connect loudspeakers or headphones to amplifiers
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R2420/00—Details of connection covered by H04R, not provided for in its groups
- H04R2420/05—Detection of connection of loudspeakers or headphones to amplifiers
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R2420/00—Details of connection covered by H04R, not provided for in its groups
- H04R2420/09—Applications of special connectors, e.g. USB, XLR, in loudspeakers, microphones or headphones
Definitions
- the present invention relates to a headphone interface technology, and in particular, to a headphone interface adaptive circuit. Background technique
- Earphone jacks of early mobile phones use dedicated interfaces or 2.5mm interfaces.
- Mobile phone headsets are also mainly used for call functions.
- Now more and more music or multimedia features are selected as 3.5mm standard interfaces.
- Headphone jack so users can choose high-quality 3.5mm stereo headphones on the market, users can also use the phone as a sound source to input to audio amplifiers or other audio equipment through the headphone jack.
- 3.5mm standard headphones There are 3 feet and 4 feet in the number of pins.
- the commonly used 4-pin 3.5mm headphone connectors follow the Japanese JEITA EIAJ RC-5325A standard in mechanical structure. This standard has been revised based on the 3-pin 3.5mm headphone connector JIS C 6560 standard, both of which define only mechanical dimensions and electrical characteristics, but do not define pin functions.
- Figure 1 is a schematic diagram showing the structure comparison of the two types of earphone plugs.
- the upper part of Figure 1 defines the common 3-pin 3.5mm stereo headphone plug: the first pin 01 is the left channel; the second pin 02 is the right channel; the third pin 03 is the ground, the 3-pin 3.5mm stereo earphone
- the circuit is shown in Figure 2.
- the lower part of Figure 1 defines the common 4-pin 3.5mm stereo headphone plug.
- the third pin 03 of the original 3-pin headphone is divided into the third pin 3 and the fourth pin 4 of the 4-pin headphone.
- the 4-pin headphones have two different pin definitions.
- the mechanical dimensions of the two headphone plugs are the same.
- 4-pin 3.5mm earphones are commonly used in mobile phones and other devices.
- One new pin is generally defined as a microphone or a microphone.
- the open mobile terminal platform OMTP, Open Mobile Terminal Platform
- Standards and commonly used standards in North America These two standards
- the definition of the first pin 1 and the second pin 2 of the plug is the same, but the third pin 3 and the fourth pin 4 are exactly opposite in the definition of the microphone and the ground, and the OMTP standard is the third pin 3 It is a mic, the fourth pin 4 is ground, and the common standard in North America is that the third pin 3 is ground and the fourth pin 4 is a mic.
- the OMTP standard 3.5mm headphone circuit diagram is shown in Figure 3.
- the North American common 3.5mm with microphone headphone circuit diagram is shown in Figure 4.
- SL is the headphone left channel speaker
- SR is the right channel speaker
- XI is the headphone plug
- Mic is the microphone
- K1 is a button for answering and making calls.
- the button K1 is used to answer and hang up the phone.
- a circuit consisting of capacitors Cl, C2 and inductor L1 is used to eliminate RF interference during a call. Zener diode D1 is used to protect Mic.
- the microphone used in the earphone is generally an electret microphone.
- the internal schematic diagram of the electret microphone is shown in Figure 5.
- the electret microphone is composed of an electret and a dedicated FET.
- the electret realizes the sound. Electric conversion function. Since the output impedance of the electret is very high and cannot be directly matched with the audio amplifier, impedance conversion is performed by a field effect transistor.
- a diode is compounded between the gate and the source of the FET, and the function of the diode is to protect the FET when it is impacted.
- Figure 6 shows the audio lines with 3.5mm male ends on both ends. In actual use, there is a 3.5mm male head and the other end is a 3.5mm female or other audio connector.
- the technical problem to be solved by the present invention is to provide an earphone interface adaptive circuit that can automatically recognize the type of earphone inserted and adjust the audio parameters to match the use of the type of earphone.
- the earphone interface adaptive circuit is installed in an electronic device supporting a 4-pin earphone socket, the circuit comprising: a control module, a headphone type identification module and a selection switch module, wherein
- the earphone type identification module is connected to the microphone interface of the electronic device, and is configured to detect a microphone bias current of the earphone device inserted into the earphone socket of the electronic device, and send the signal to the control module;
- the control module identifies the earphone type device inserted into the earphone socket of the electronic device according to the microphone bias current, and controls the selection switch module to connect the third pin and the fourth pin of the earphone socket of the electronic device to the microphone interface and the ground of the electronic device respectively Or respectively connected to the ground and the microphone interface of the electronic device, and configure corresponding audio channels for the earphone type device.
- the earphone type identification module includes a series current detecting circuit and a bias resistor, wherein the detected microphone bias current is Imic, the electret microphone bias voltage is Mic-bias, and the diode of the electret microphone is guided.
- the pass voltage is Vf;
- the selection switch module connects the third pin and the fourth pin of the earphone socket to the microphone interface and the ground respectively, and is matched with the OMTP standard 4-pin earphone by default, and the control module inserts the electronic device according to the microphone bias current pair.
- the headset device of the device's headphone jack is identified, including the following:
- the current detection circuit detects 100 ⁇ A Imic ⁇ 500 ⁇ A, it recognizes that the OMTP standard 4-pin headphone plug is inserted;
- the current detecting circuit detects 0.9 ( Mic - bias - Vf ) / R5 ⁇ Imic ⁇ lK Mic - bias - Vf ) / R5 , it recognizes that the plug is a standard 4 - foot headphone plug in North America, and R5 is a bias resistor;
- the current detection circuit detects Imic > 1.1 (Mic-bias-Vf) / R5, it recognizes that the three-legged headphone device is inserted.
- control module connects the third pin and the fourth pin of the earphone socket of the electronic device to the microphone interface and the ground of the electronic device or to the ground of the electronic device respectively according to the microphone bias current control selection switch module.
- the microphone, and configuring the corresponding audio channel for the earphone device specifically includes:
- control module configures an audio channel for the inserted headset device in accordance with the OMTP standard
- the control module controls the selection switch module to connect the third pin and the fourth pin of the earphone socket of the electronic device respectively The ground and the mic interface of the electronic device, and then the audio channel is configured for the inserted earphone device according to the commonly used standard in North America;
- the control module configures an audio channel for the inserted three-pin headphones type device.
- the earphone type identification module includes a series current detecting circuit and a bias resistor, wherein the detected microphone bias current is Imic, the electret microphone bias voltage is Mic-bias, and the diode of the electret microphone is guided.
- the pass voltage is Vf;
- the selection switch module connects the third pin and the fourth pin of the headphone jack to the ground and microphone interfaces respectively.
- the default is to adapt to the North American standard 4-pin headphone, and the control module is inserted according to the microphone bias current pair.
- the earphone-type device of the earphone socket of the electronic device is identified, including the following situations:
- the current detection circuit detects 100 microamps of Imic ⁇ 500 microamps, it recognizes that the plug-in is a commonly used standard 4-pin headphone plug in North America; When the current detecting circuit detects 0.9 ( Mic - bias - Vf ) / R5 ⁇ Imic ⁇ lK Mic - bias - Vf ) / R5, it recognizes that the OMTP standard 4-pin headphone plug is inserted, and R5 is a bias resistor;
- control module connects the third pin and the fourth pin of the earphone socket of the electronic device to the microphone interface and the ground of the electronic device or to the ground of the electronic device respectively according to the microphone bias current control selection switch module.
- the microphone, and configuring the corresponding audio channel for the earphone device specifically includes:
- control module configures an audio channel for the inserted headset device according to the commonly used standards in North America;
- the control module controls the selection switch module to connect the third pin and the fourth pin of the earphone socket of the electronic device respectively a microphone interface and a ground of the electronic device, and then configuring an audio channel for the inserted earphone device according to the OMTP standard;
- the control module configures an audio channel for the inserted three-pin headphones type device.
- the circuit further includes a three-legged earphone type device identification module
- the three-legged earphone type device identification module includes a second resistor and a fourth resistor connected in series, and an operating voltage
- VDD is grounded through the second resistor and the fourth resistor in turn, the first pin or the second pin of the earphone socket of the electronic device, and the second control end of the control module are connected between the second resistor and the fourth resistor, the control module
- the highest voltage of the second control terminal input is VDD x ( R4//Re ) / ( R2+ R4//Re ), R2 is the second resistor, R4 is the fourth resistor, and Re is the 3-pin headphone speaker impedance. ;
- the control module configures an audio channel for the inserted three-leg headphone device, which specifically includes: When the second control terminal of the control module is input low, the earphone socket of the electronic device is a 3-pin earphone, and the control module configures an audio channel for the inserted 3-pin earphone;
- the 3-pin audio cable is inserted into the earphone socket of the electronic device, and the control module configures the audio channel for the inserted 3-pin audio cable.
- the circuit further includes a device insertion detection module
- the device insertion detecting module includes a first resistor and a third resistor, and the working voltage VDD is connected to the sixth pin of the earphone socket of the electronic device through the first resistor, and the first pin of the earphone socket of the electronic device is grounded through the third resistor, and the control module is The first control end is connected to the sixth pin of the earphone socket, and the highest voltage input to the first control terminal is low level is ⁇ 00 1 3/ (1 1+1 3 ), R1 is the first resistance, and R3 is the third Resistance
- the first pin and the sixth pin of the earphone socket of the electronic device are in contact, and the first control end of the control module is at a low level;
- the first pin and the sixth pin of the earphone socket of the electronic device are separated, and the first control end of the control module is at a high level.
- the circuit further includes a device insertion detection module
- the device insertion detecting module includes a first resistor and a third resistor, the working voltage VDD is connected to the fifth pin of the earphone socket of the electronic device through the first resistor, and the second pin of the earphone socket of the electronic device is grounded through the third resistor, and the control module is The first control terminal is connected to the fifth pin of the earphone socket, and the highest voltage input to the first control terminal is low level is ⁇ 00 1 3/ (1 1+1 3 ), R1 is the first resistance, and R3 is the third Resistance
- the second pin and the fifth pin of the earphone socket of the electronic device are in contact, and the first control end of the control module is at a low level
- the second pin and the fifth pin of the earphone socket of the electronic device are separated, and the first control end of the control module is at a high level.
- the control module detects that the first control port is high through the device insertion detection module At the level, the electret microphone bias voltage is turned on and input to the earphone type recognition module.
- control module uses Qualcomm's QSC6155 chip
- current detecting circuit uses Qualcomm's PM8028 chip
- control module and the current detecting circuit use a Qualcomm QSC6055 chip
- the selector switch module is a controllable double pole double throw switch.
- the present invention has at least the following advantages:
- the earphone interface adaptive circuit of the invention is installed in an electronic device supporting a 4-pin headphone socket, and the control module detects the microphone bias current detected by the earphone type identification module to be inserted into the OMTP standard 4-pin earphone, and the commonly used standard in North America.
- the 4-pin earphone is also a 3-pin stereo earphone or a 3-pin audio cable.
- the control module can exchange the connection relationship between the electronic device earphone socket and the microphone interface and the ground signal by controlling the selection switch module, so that the earphone interface adaptive circuit can be Switch between the inserted OMTP interface headset or the North American common interface headset, and support both headsets.
- the circuit of the present invention is applied to an electronic device such as a mobile phone, so that the earphone interface of the device such as a mobile phone can automatically recognize the earphone type, and automatically adjust the interface circuit and the audio channel according to the recognized earphone type to adapt to the inserted earphone type device.
- Figure 1 shows a comparison of the structure of a 3-pin 3.5mm headphone connector and a 4-pin 3.5mm headphone connector
- Figure 2 is a circuit diagram of a 3-pin stereo headset
- Figure 3 shows the OMTP pin definition 4-pin stereo headphone circuit diagram
- Figure 4 shows the four-pin stereo headphone circuit diagram for common pin definitions in North America
- FIG. 5 is an internal circuit diagram of the electret microphone
- Figure 6 is a schematic diagram of the structure of a dual male stereo audio line
- FIG. 7 is a schematic diagram of an adaptive circuit of a headphone interface according to a first embodiment of the present invention.
- FIGS. 9( a ) and ( b ) are respectively equivalent circuit diagrams of the three-legged earphone type device identification module when the 3-pin audio cable and the 3-pin earphone are inserted into the earphone socket;
- FIG. 10 is a schematic diagram of an adaptive circuit of a headphone interface according to a second embodiment of the present invention.
- FIG. 11 is a schematic diagram of an adaptive circuit of a headphone interface according to a third embodiment of the present invention.
- FIG. 12 is a schematic diagram of an adaptive circuit of a headphone interface according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments.
- the earphone interface adaptive circuit of the present invention is installed in a headphone or similar electronic device supporting a 4-pin earphone socket, and is first detected by means of mechanical detection by using a device insertion detecting module. Is there a device plugged in? If a device insertion is detected, the electret microphone bias voltage in the electronic device is turned on and the microphone bias current is detected, and the microphone is forward biased, the microphone reverse biased, and the microphone is shorted to the ground. The bias current is different.
- the microphone bias current can be used to distinguish whether the OMTP interface earphone, the North American common interface earphone or the 3-pin stereo earphone or the 3-pin audio cable.
- a controllable double-pole double-throw switch is further introduced, which can control the connection between the earphone socket of the electronic device and the microphone interface and the ground signal of the electronic device, so that the earphone interface adaptive circuit can be based on the inserted OMTP interface earphone. Or switch between the commonly used interface headphones in North America, and support both types of headphones.
- the 3-pin earphone or the 3-pin audio cable Since the 3-pin earphone or the 3-pin audio cable is inserted, it is equivalent to short-circuiting the microphone interface and the ground on the electronic device, so it cannot be distinguished by the microphone bias current. Because the difference between the 3-pin earphone and the 3-pin audio cable is that the left-right channel of the 3-pin earphone has a relationship with the ground, and the impedance to the ground is generally 32 ohms. The impedance of the left and right channels of the 3-pin audio cable is infinite when the other end of the 3-pin audio cable is not connected to a car audio or audio amplifier, even if the other end of the 3-pin audio cable has been connected to the car audio or audio.
- a three-legged headphone device identification module is designed to determine the magnitude of the left or right channel ground resistance to determine whether the inserted device is a 3-pin earphone or a 3-pin audio cable.
- the method described in this manual is based on a 3.5mm headphone device for mobile phones, but is not limited to mobile phones and 3.5mm headphones.
- FIG. 7 is an adaptive circuit diagram of a headphone interface in the embodiment, the headphone interface adaptive circuit includes: a device insertion detection module, a control module, a headphone type identification module, a selection switch module, and a three-leg headphone device.
- the identification module the main controller of the mobile phone or similar electronic device, can use Qualcomm's QSC6155 chip.
- the headphone jack J1 is a common 4-pin headphone jack.
- the headphone jack J1 has a fifth pin 5 and a sixth pin 6 in addition to the first pin 1 to the fourth pin 4 pin corresponding to the plug, usually the earphone
- the first pin 1 of the socket J1 is connected to the left channel interface on the main controller through the first DC blocking capacitor C1
- the second pin 2 of the headphone socket J1 is connected to the main controller through the second DC blocking capacitor C2.
- Right channel interface is a common 4-pin headphone jack.
- the first pin 1 and the sixth pin 6 are in contact internally, and the second pin 2 and the fifth pin 5 are also in contact; when the 4-pin headphone plug is After the headphone jack J1 is inserted, the first pin 1 and the sixth pin 6 are internally separated, and the second pin 5 and the fifth pin 5 are also separated.
- the device insertion detection module cooperates with the earphone socket J1 to implement the headphone plug detection function.
- the device insertion detection module includes a first resistor R1 and a third resistor R3.
- the third resistor R3 is much smaller than the first resistor R1, and the working voltage VDD passes through the first resistor.
- R1 is connected to the sixth pin 6 of the headphone jack J1, the first pin 1 of the headphone jack J1 is grounded through the third resistor R3, and the first control end H DET1 of the control module is connected to the sixth pin 6 of the headphone jack J1.
- the equivalent circuit is shown in Figure 8 (a).
- the main controller of the mobile phone or similar electronic device can determine whether a device is inserted by identifying the level of the first control terminal H DET1.
- the main controller detects that the first control port H_DET1 is high through the device insertion detection module, the microphone bias voltage Mic-bias power is turned on and input to the earphone type identification module.
- the values of the first resistor R1 and the third resistor R3 in Figures 7 and 8 can mainly consider two points:
- the first resistor R1 and the third resistor R3 are both larger, generally 10K ohms or more, so that the circuit operating current will be smaller;
- the earphone type identification module includes a current detecting circuit D2 and a biasing resistor R5 connected in series in FIG.
- the current detection circuit D2 uses Qualcomm's PM8028 chip, and the bias resistor R5 is used to supply the appropriate voltage to the FET drain in the electret microphone.
- Mic-bias is the bias voltage provided by the mobile device and other similar electronic devices to the electret microphone.
- the third DC blocking capacitor C3 is the main controller microphone port.
- the value of the bias resistor R5 is generally close to the output impedance of the electret microphone.
- the commonly used microphone output impedance of the earphone is 2.2K ohms, so the bias resistor R5 is also set to 2.2K ohms.
- the value of the microphone bias voltage Mic-bias is also related to the characteristics of the microphone.
- the commonly used microphone bias voltage Mic-bias is 2V.
- the OMTP standard 3.5mm 4-pin headphones and the commonly used standard 3.5mm 4-pin headphones in North America are on the pin definition.
- the microphone and the ground are exactly the opposite.
- the ground pin just covers 4 The mic and ground pins of the footphone.
- the current detection circuit has been integrated in the analog baseband part of many mobile phones, generally no additional design is required, such as Qualcomm's QSC6055 platform and QSC6155+.
- the PM8028 platform integrates a current-sense circuit to detect the mic bias current.
- the default state of the double-pole double-throw switch is the fourth pin 4 of the headphone jack J1, and the third pin is connected to the microphone interface Mic.
- the default is the OMTP standard headphone definition.
- the current detecting circuit D2 detects the current of the microphone biasing the power source. If the OMTP standard 4-pin earphone is inserted, the microphone is forward-biased, and the forward bias current of the microphone is related to the characteristics of the dedicated FET inside the microphone. The field effect transistor gate voltage is determined in the case of field effect.
- the tube is a constant current source, basically independent of the external bias voltage Mic-bias and bias resistor R5, generally 100 ⁇ 350 microamperes, the maximum does not exceed 500 microamperes, and the bias current detected by the current detecting circuit D2 is recorded as Imic, if 100 microamps of Imic 500 microamps are detected, it can be judged that the OMTP standard 4-pin earphone is inserted.
- the main controller configures the audio channel for the inserted earphone-type device according to the OMTP standard.
- the sending direction is on the earphone. Mike, the receiver is in the direction of the speaker on the headset. After the setup, the phone or similar electronic device can do other processing.
- the microphone bias current is due to the Zener diode ( Figure 3, Figure 4, D1, the frequently selected model is 1N4737, etc., so the microphone bias current Imic « ( Mic - bias-Vf ) / R5 , where Vf is the forward voltage of the Zener diode, and the normal conduction current If at room temperature is about 1mA, 0.7V about.
- the fourth pin 4 of Jl is connected to the microphone interface Mic, the third pin 3 is grounded, the microphone is forward biased, and then the audio channel is configured for the inserted earphone type device according to the commonly used standard in North America.
- the bias resistor R5 2.2K ohm
- the bias voltage Mic ⁇ bias 2V
- (0.9 Mic_bias-0.7) /R5 0.9 (2.0-0.7)
- the maximum value of the bias voltage is 500 ⁇ A.
- the current range can be relaxed appropriately, that is, when the current detection circuit D2 detects Imic > 1.1 ( Mic_bias- 0.7 ) /R5 , you can think of a 3-pin or 3-pin audio cable.
- the Imic is usually greater than 750 ⁇ A at this time and is in the short-circuit current range, it will affect the standby time, so it is better to turn off the Mic-bias power supply.
- Imic is not in the above range, then an unrecognized device is inserted.
- a pop-up window on the phone prompts the user not to recognize the inserted device.
- the phone can do other processing.
- the three-pin earphone type device recognition module composed of the second resistor R2 and the fourth resistor R4 can be used to distinguish whether it is a 3-pin earphone or a 3-pin audio cable, and the second resistor R2 is much smaller than the fourth resistor R4.
- a 3-pin earphone or a 3-pin audio cable is inserted, that is, the third pin 3 of the 3-pin earphone or the 3-pin audio cable plug of FIG. 2 or FIG. 6 and the third pin 3 and the third pin of the headphone jack J1 of FIG.
- Four-pin 4 simultaneous contact the second pin 2 of the 3-pin audio or 3-pin audio cable plug and the second pin 2 of the headphone jack J1, the first pin 1 of the 3-pin audio or 3-pin audio cable plug
- the first pin 1 of the headphone jack J1 is in contact.
- the working voltage VDD is grounded through the second resistor R2 and the fourth resistor R4 in sequence, the earphone socket
- the second pin 2 of J1 and the second control terminal H_DET2 of the main controller are both connected between the second resistor R2 and the fourth resistor R4.
- the equivalent circuit of the second control terminal H-DET2 of the main controller is as shown in Fig. 9(a), because The second resistor R2 is much smaller than the fourth resistor R4, so the second control terminal H_DET2 of the main controller is at a high level.
- a resistor equivalent to 32 ohms is connected between the second pin 2 of the headphone jack J1 and the ground, that is, the 3-pin headphone speaker impedance Re, and the three-leg headphone type device at this time
- the partial equivalent circuit of the identification module connected to the second control terminal H_DET2 is as shown in FIG. 9(b), and the parallel resistance of the 3-pin earphone speaker impedance Re and the fourth resistor R4 is much smaller than the second resistance R2, and the second Control terminal H - DET2 is low.
- the second control terminal H_DET2 it can be distinguished whether the 3-pin earphone or the 3-pin audio cable is inserted.
- the highest voltage that ensures that the second control terminal H_DET2 of the main controller is low is VDD ( R4//Re ) / ( R2+ R4//Re ), where all values above this value are input high, including when no device is plugged in and when the 3-pin audio line is plugged in, the second control input is averaged between VDD ( R4//Re )/( R2+ R4/// Between Re) and VDD x ( R4 ) / ( R2+ R4 ), R4//Re is the parallel resistance of the fourth resistor and the 3-pin headphone speaker impedance Re.
- the second resistor R2 47K ohms
- the 3-pin earphone is inserted into the earphone socket of the electronic device, and the control module configures an audio channel for the inserted 3-pin earphone, so that the mobile phone and the like are in the process of talking.
- the microphone on the phone when sending, and use the headphone jack when receiving. Next, you can do other processing of the phone.
- the 3-pin audio cable is inserted into the earphone socket of the electronic device, and the control module needs to configure an audio channel for the inserted 3-pin audio cable.
- Make the mobile phone and other similar electronic devices use the microphone on the mobile phone during the call, use the earphone interface when receiving, and set the audio parameters to the hands-free mode. After the sound is connected to other large volume devices through the audio cable, the whistle occurs during the call. Self-excited. Then do other processing of the phone.
- the left channel headphone output interface H-L and the right channel headphone output interface H-R, and the microphone interface Mic are connected to the audio interface of the headphone type electronic device main controller.
- the second embodiment of the present invention is substantially the same as the first embodiment, and the difference is:
- connection detection module and the three-pin headphone type device identification module are connected with the pins of the headphone socket J1;
- Double-pole double-throw switch The initial default state of D1.
- the earphone interface adaptive circuit includes: a device insertion detection module, a control module, a headphone type identification module, a selection switch module, and a three-leg headphone device identification module, and the control module is a mobile phone. Or the main controller of similar electronic equipment, you can use Qualcomm's QSC6055 chip.
- the device insertion detection module cooperates with the earphone socket J1 to implement the headphone plug detection function.
- the device insertion detection module includes a first resistor R1 and a third resistor R3.
- the third resistor R3 is much smaller than the first resistor R1, and the working voltage VDD passes through the first resistor.
- R1 is connected to the fifth pin 5 of the headphone jack J1, the second pin 2 of the headphone jack J1 is grounded through the third resistor R3, and the first control end H DET1 of the control module is connected to the fifth pin 5 of the headphone jack J1.
- the main controller of the mobile phone or similar electronic device can determine whether a device is inserted by identifying the level of the first control terminal H DET1. When the main controller is plugged in through the device When the detection module detects that the first control port H_DET1 is at a high level, the microphone bias voltage Mic_bias is turned on and input to the earphone type identification module.
- the values of the first resistor R1 and the third resistor R3 in Fig. 10 and Fig. 8 can mainly consider two points:
- the first resistor R1 and the third resistor R3 are both larger, generally 10K ohms or more, so that the circuit operating current will be smaller;
- the earphone type identification module includes the current detecting circuit D2 and the bias resistor connected in series in FIG.
- the function of the current detecting circuit D2 is also performed by Qualcomm as the main controller.
- the QSC6055 chip is used to complete the bias resistor R5 to provide the appropriate voltage to the FET drain in the electret microphone.
- Mic-bias is the bias voltage provided by the mobile device and other similar electronic devices to the electret microphone.
- the third DC blocking capacitor C3 is the DC blocking capacitor of the main controller microphone port Mic. Bias resistor
- the value of R5 is generally close to the output impedance of the electret microphone.
- the commonly used microphone output impedance of the earphone is
- the bias resistor R5 is also set to 2.2K ohms.
- Mic-bias is also related to the characteristics of the microphone.
- the commonly used microphone bias voltage Mic-bias is 2V.
- the OMTP standard 3.5mm 4-pin headphones and the commonly used standard 3.5mm 4-pin headphones in North America are on the pin definition.
- the microphone and the ground are exactly the opposite.
- the ground pin just covers 4 The mic and ground pins of the footphone.
- a controllable double-pole double-throw switch chip D 1 and a current detecting circuit D2 are introduced to realize the detection of the earphone type.
- the current detecting circuit is integrated in the analog baseband portion of many mobile phones, and generally does not require an additional design, such as QSC6055 in Qualcomm. Both the platform and the QSC6155+PM8028 platform integrate current sensing A circuit that detects the mic bias current.
- the default state of the double-pole double-throw switch is the fourth pin of the headphone jack J1. 4 is connected to the microphone interface Mic, and the third pin is grounded to the ground. The default is the standard definition of the standard headphones in North America.
- the current detecting circuit D2 detects the current of the microphone biasing the power source. If you insert a commonly used standard 4-pin earphone in North America, the microphone is forward-biased. The forward bias current of the microphone is related to the characteristics of the dedicated FET inside the microphone.
- the field The effect tube is a constant current source, and the basic and external bias voltages Mic-bias and bias resistor R5 are independent, generally 100 ⁇ 350 microamperes, and the maximum is less than 500 microamperes, and the bias current detected by the current detecting circuit D2 is recorded.
- the main controller configures an audio channel for the inserted earphone-type device according to the commonly used standards in North America.
- the microphone on the earphone receives the direction of the speaker on the earphone. After the setup, the phone or similar electronic device can do other processing.
- the microphone bias current is due to the diode between the gate and the source of the FET, so the microphone
- the bias current Imic - ( Mic - bias - Vf ) / R5 where Vf is the turn-on voltage of the diode and is about 0.7V.
- the bias resistor R5 2.2K ohms
- the bias voltage Mic bias 2V
- Imic is usually greater than 750 ⁇ A at this time and is in the short-circuit current range, it will affect the standby time, so it is best to turn off the Mic-bias power supply.
- Imic is not in the above range, then an unrecognized device is inserted.
- a pop-up window on the phone prompts the user not to recognize the inserted device.
- the phone can do other processing.
- the three-leg headphone type device recognition module composed of the second resistor R2 and the fourth resistor R4 can be used to distinguish whether it is a 3-pin earphone or a 3-pin audio cable, and the second resistor R2 is much smaller than the fourth resistor R4.
- the working voltage VDD is grounded through the second resistor R2 and the fourth resistor R4 in turn, and the first pin 1 of the headphone jack J1 and the second control end H_DET2 of the main controller are connected to the second resistor R2 and the fourth resistor R4. between.
- the equivalent circuit of the second control terminal H-DET2 of the main controller is as shown in Fig. 9(a), because The second resistor R2 is much smaller than the fourth resistor R4, so the second control terminal H_DET2 of the main controller is at a high level.
- a resistor equivalent to 32 ohms is connected between the second pin 2 of the headphone jack J1 and the ground, that is, the 3-pin earphone speaker impedance Re, at this time, the three-legged earphone
- the partial equivalent circuit of the class device identification module and the second control terminal H-DET2 is as shown in FIG. 9(b), and the parallel resistance value of the 3-pin earphone speaker impedance Re and the fourth resistor R4 is much smaller than the second resistance R2.
- the second control terminal H_DET2 is at a low level.
- the second control terminal H_DET2 it can be distinguished whether the 3-pin earphone or the 3-pin audio cable is inserted.
- the highest voltage that ensures that the second control terminal H_DET2 of the main controller is low is VDD ( R4//Re ) / ( R2+ R4//Re ), where all values above this value are input high, including when no device is plugged in and when the 3-pin audio line is plugged in, the second control input is averaged between VDD ( R4//Re )/( R2+ R4// Re ) and VDD ( R4 ) / ( R2+ R4 ).
- the second resistor R2 47K ohms
- the 3-pin earphone is inserted into the earphone socket of the electronic device, and the control module configures an audio channel for the inserted 3-pin earphone, so that the mobile phone and the like are in the process of talking.
- the microphone on the phone when sending, and use the headphone jack when receiving. Next, you can do other processing of the phone.
- the control module When the second control terminal H_DET2 of the control module is input to a high level, the 3-pin audio cable is inserted into the earphone socket of the electronic device, and the control module needs to configure an audio channel for the inserted 3-pin audio cable, so that the mobile phone and the like are in the electronic device.
- the microphone on the mobile phone is used for sending, and the earphone interface is used for receiving.
- the audio parameter is set to the hands-free mode. After the sound is connected to other large volume devices through the audio cable, the whistling self-excitation occurs during the call. Then do other processing of the phone.
- the third embodiment of the present invention is substantially the same as the first embodiment.
- the earphone interface adaptive circuit of the embodiment does not include the device insertion detecting module.
- the earphone interface adaptive circuit only Including: control module, earphone type identification module, selection switch module and three-leg headphone type device identification module.
- the microphone bias voltage Mic bias needs to be turned on for a long time. Once a device is inserted into the earphone socket J1, the microphone bias current can be detected.
- the disadvantage is that the power consumption is relatively high, which may cause the standby time of the mobile phone to be shortened.
- the fourth embodiment of the present invention is substantially the same as the first embodiment.
- the headset interface adaptive circuit of the embodiment does not include a three-legged headset device identification module.
- the headset interface is adaptive.
- the circuit only includes: a device insertion detection module, a control module, a headphone type identification module, and a selection switch module.
- the earphone type identification module recognizes the OMTP standard earphone, the North American common standard earphone, and the three-leg earphone type device, it is impossible to further distinguish whether the three-legged earphone type device is a 3-pin earphone or a 3-pin audio cable. Therefore, the present implementation
- the headphone interface adaptive circuit described in the example is only applicable to the case of only the 4-pin OMTP standard earphone and the North American standard standard earphone.
- the earphone interface adaptive circuit of the invention is installed in an electronic device supporting a 4-pin headphone jack, and the control module detects the microphone bias current detected by the current detecting circuit to be inserted into the OMTP standard 4-pin earphone, and the North American common standard 4
- the footphone is also a 3-pin stereo earphone or a 3-pin audio cable.
- the control module can exchange the connection relationship between the electronic device earphone socket and the microphone interface and the ground signal by controlling the selection switch module, so that the earphone interface adaptive circuit can be The inserted OMTP interface headset or the North American common interface headset is switched, and both headsets are supported.
- the circuit of the present invention is applied to an electronic device such as a mobile phone, so that the earphone interface of the device such as a mobile phone can automatically recognize the type of the earphone, and automatically adjust the interface circuit and the audio channel according to the recognized type of the earphone to adapt to the inserted earphone type device.
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Abstract
The present invention discloses an adaptive circuit of an earphone interface. The circuit is mounted in an electronic device supporting a four-pin earphone jack. A control module distinguishes that the plugged is a four-pin earphone of the Open Mobile Terminal Platform (OMTP) standard, a four-pin earphone of commonly used standard in North America or a 3-pin stereophonic earphone or a 3-pin audio line according to a microphone bias current detected by a current detecting module; by controlling a selective switch module, the control module makes the connection relation of the earphone jack and a microphone interface and the connection relation of the earphone jack and ground signal switch from each other, so that the adaptive circuit of the earphone interface carries out switch according to the plugged earphone with OMTP interface or the plugged earphone with North America commonly used interface and supports both earphones. By applying the circuit of the present invention to the electronic device such as a handset and so on, the earphone interface of the device such as a handset and so on can identify the type of the earphone automatically and automatically adjust the interface circuit and audio channels to adapt to the plugged earphone-type device according to the identified type of the earphone.
Description
一种耳机接口自适应电路 技术领域 Headphone interface adaptive circuit
本发明涉及耳机接口技术, 尤其涉及一种耳机接口自适应电路。 背景技术 The present invention relates to a headphone interface technology, and in particular, to a headphone interface adaptive circuit. Background technique
手机或其他音频设备很多都具有耳机接口, 早期手机的耳机接口多用 专用接口或者 2.5mm接口, 手机耳机也主要用于通话功能, 现在越来越多 的音乐或者多媒体特色手机选用 3.5mm标准接口作为耳机接口, 这样用户 可以选用市面上高品质的 3.5mm立体声耳机, 用户也可以将手机作为一个 音源通过耳机接口输入到音频功放或者其他音响设备。 3.5mm标准的耳机 在引脚数量上有 3脚和 4脚之分, 常用的 4脚 3.5mm耳机连接器在机械结 构上遵循日本 JEITA EIAJ RC-5325A标准。 此标准是在 3脚 3.5mm耳机连 接器 JIS C 6560标准的基础上修订而来的, 上述两个标准都仅定义了机械 尺寸和电气特性, 但是没有对引脚功能进行定义。 Many mobile phones or other audio devices have a headphone jack. Earphone jacks of early mobile phones use dedicated interfaces or 2.5mm interfaces. Mobile phone headsets are also mainly used for call functions. Now more and more music or multimedia features are selected as 3.5mm standard interfaces. Headphone jack, so users can choose high-quality 3.5mm stereo headphones on the market, users can also use the phone as a sound source to input to audio amplifiers or other audio equipment through the headphone jack. 3.5mm standard headphones There are 3 feet and 4 feet in the number of pins. The commonly used 4-pin 3.5mm headphone connectors follow the Japanese JEITA EIAJ RC-5325A standard in mechanical structure. This standard has been revised based on the 3-pin 3.5mm headphone connector JIS C 6560 standard, both of which define only mechanical dimensions and electrical characteristics, but do not define pin functions.
图 1 是这两种耳机插头的结构对比示意图。 图 1 上部是对常见 3 脚 3.5mm立体声耳机插头的定义: 第一引脚 01为左声道; 第二引脚 02为右 声道; 第三引脚 03为地, 3脚 3.5mm立体声耳机的电路如图 2所示。 图 1 下部是对常见 4脚 3.5mm立体声耳机插头的定义, 即将原先 3脚耳机第三 引脚 03分割成了 4脚耳机的第三引脚 3和第四引脚 4这两个引脚, 4脚耳 机又有两种不同的引脚定义, 除此之外, 这两种耳机插头的机械尺寸是一 样的。 Figure 1 is a schematic diagram showing the structure comparison of the two types of earphone plugs. The upper part of Figure 1 defines the common 3-pin 3.5mm stereo headphone plug: the first pin 01 is the left channel; the second pin 02 is the right channel; the third pin 03 is the ground, the 3-pin 3.5mm stereo earphone The circuit is shown in Figure 2. The lower part of Figure 1 defines the common 4-pin 3.5mm stereo headphone plug. The third pin 03 of the original 3-pin headphone is divided into the third pin 3 and the fourth pin 4 of the 4-pin headphone. The 4-pin headphones have two different pin definitions. In addition, the mechanical dimensions of the two headphone plugs are the same.
4脚 3.5mm耳机常用于手机等设备, 新增的一个引脚一般定义为麦克 即话筒, 但是在麦克引脚的定义上有两种标准, 分别为开放移动终端平台 ( OMTP , Open Mobile Terminal Platform )标准和北美常用标准。 这两种标
准在插头第一引脚 1和第二引脚 2的定义是一致的, 但是第三引脚 3和第 四引脚 4在麦克和地的定义上正好相反, OMTP标准为第三引脚 3是麦克、 第四引脚 4是地, 而北美常用标准为第三引脚 3是地、 第四引脚 4是麦克。 4-pin 3.5mm earphones are commonly used in mobile phones and other devices. One new pin is generally defined as a microphone or a microphone. However, there are two standards for the definition of the microphone pin, namely the open mobile terminal platform (OMTP, Open Mobile Terminal Platform). Standards and commonly used standards in North America. These two standards The definition of the first pin 1 and the second pin 2 of the plug is the same, but the third pin 3 and the fourth pin 4 are exactly opposite in the definition of the microphone and the ground, and the OMTP standard is the third pin 3 It is a mic, the fourth pin 4 is ground, and the common standard in North America is that the third pin 3 is ground and the fourth pin 4 is a mic.
OMTP标准 3.5mm耳机电路图见图 3 , 北美常用 3.5mm带麦克耳机电路图 见图 4。 图 3、 图 4中, SL是耳机左声道扬声器, SR是右声道扬声器, XI 是耳机插头, Mic是麦克, K1是一个按键, 用于接听和拨打电话。 图中除 了左右声道扬声器、 连接器和麦克外还有一些辅助电路, 按键 K1用于接听 和挂断电话。 电容 Cl、 C2和电感 L1组成的电路用于消除通话时的射频干 扰。 稳压二极管 D1用于保护 Mic。 The OMTP standard 3.5mm headphone circuit diagram is shown in Figure 3. The North American common 3.5mm with microphone headphone circuit diagram is shown in Figure 4. In Figure 3 and Figure 4, SL is the headphone left channel speaker, SR is the right channel speaker, XI is the headphone plug, Mic is the microphone, and K1 is a button for answering and making calls. In addition to the left and right channel speakers, connectors and mics, there are some auxiliary circuits. The button K1 is used to answer and hang up the phone. A circuit consisting of capacitors Cl, C2 and inductor L1 is used to eliminate RF interference during a call. Zener diode D1 is used to protect Mic.
耳机上用的麦克, 一般是驻极体麦克风, 驻极体麦克风的内部原理图 如图 5 所示, 驻极体麦克风内部由驻极体和专用场效应管两部分构成, 驻 极体实现声电转换功能。 因驻极体的输出阻抗很高, 不能直接与音频放大 器匹配, 所以用一个场效应管进行阻抗转换。 另外场效应管的栅极和源极 之间又复合有一个二级管, 此二级管的作用是在场效应管受冲击时起保护 作用。 The microphone used in the earphone is generally an electret microphone. The internal schematic diagram of the electret microphone is shown in Figure 5. The electret microphone is composed of an electret and a dedicated FET. The electret realizes the sound. Electric conversion function. Since the output impedance of the electret is very high and cannot be directly matched with the audio amplifier, impedance conversion is performed by a field effect transistor. In addition, a diode is compounded between the gate and the source of the FET, and the function of the diode is to protect the FET when it is impacted.
另外, 手机需要将声音输出到汽车音响或功放设备等之类的音频设备 时, 常用起延长作用的音频线。 图 6中画出的是两头都是 3.5mm公头的音 频线, 实际使用中还有一头是 3.5mm公头, 另一头是 3.5mm母头或其他音 频接头形式的音频线。 In addition, when the mobile phone needs to output sound to an audio device such as a car stereo or a power amplifier device, an extended audio cable is often used. Figure 6 shows the audio lines with 3.5mm male ends on both ends. In actual use, there is a 3.5mm male head and the other end is a 3.5mm female or other audio connector.
传统耳机接口设计上, 只检测耳机是否插入和拔出, 不对耳机的类型 进行识别, 这样就会造成对于不支持的耳机插入后, 手机的功能异常。 比 如, 3脚的立体声耳机, 由于耳机上没有麦克风, 插入到手机后, 如果不做 识别和处理, 用耳机通话时对方就无法听到声音。 即使同样是 4脚的耳机, 北美标准接口的耳机插入到 OMTP标准的耳机座中, 或者 OMTP标准的耳 机插入到北美常用标准接口的耳机中, 也会导致声音变小或听不到声音的
问题。 In the traditional earphone interface design, only the earphones are inserted and removed, and the type of the earphone is not recognized. This will cause the function of the mobile phone to be abnormal after the unsupported earphone is inserted. For example, a 3-pin stereo headset, because there is no microphone on the headset, after being inserted into the phone, if it is not recognized and processed, the other party cannot hear the sound when talking with the headset. Even if it is a 4-pin headset, the North American standard interface headphones are plugged into the OMTP standard headphone jack, or the OMTP standard headphones are plugged into the headphones of the standard interface in North America, which can cause the sound to become small or audible. Question.
因此就需要用一种电路在检测到耳机插入后, 能自动识别插入的耳机 类型, 并能根据所插入的耳机类型, 自动调整成相匹配的电路并自动调整 必要的音频参数。 发明内容 Therefore, it is necessary to automatically recognize the type of the inserted earphone after detecting the insertion of the earphone, and automatically adjust the matching circuit to automatically adjust the necessary audio parameters according to the type of the inserted earphone. Summary of the invention
本发明要解决的技术问题是, 提供一种耳机接口自适应电路, 能自动 识别插入的耳机类型并调整音频参数以配合该类型耳机的使用。 The technical problem to be solved by the present invention is to provide an earphone interface adaptive circuit that can automatically recognize the type of earphone inserted and adjust the audio parameters to match the use of the type of earphone.
本发明釆用的技术方案是, 所述耳机接口自适应电路, 安装在一个支 持 4脚耳机插座的电子设备中, 该电路包括: 控制模块, 耳机类型识别模 块和选择开关模块, 其中, The technical solution of the present invention is that the earphone interface adaptive circuit is installed in an electronic device supporting a 4-pin earphone socket, the circuit comprising: a control module, a headphone type identification module and a selection switch module, wherein
耳机类型识别模块与电子设备的麦克接口相连, 用于检测插入电子设 备耳机插座的耳机类设备的麦克偏置电流, 发送给控制模块; The earphone type identification module is connected to the microphone interface of the electronic device, and is configured to detect a microphone bias current of the earphone device inserted into the earphone socket of the electronic device, and send the signal to the control module;
控制模块根据麦克偏置电流对插入电子设备耳机插座的耳机类设备进 行识别, 并控制选择开关模块将电子设备耳机插座的第三引脚和第四引脚 分别连接到电子设备的麦克接口和地或者分别连接到电子设备的地和麦克 接口, 并为所述耳机类设备配置相应音频通道。 The control module identifies the earphone type device inserted into the earphone socket of the electronic device according to the microphone bias current, and controls the selection switch module to connect the third pin and the fourth pin of the earphone socket of the electronic device to the microphone interface and the ground of the electronic device respectively Or respectively connected to the ground and the microphone interface of the electronic device, and configure corresponding audio channels for the earphone type device.
进一步的, 所述耳机类型识别模块包括串联的电流检测电路和偏置电 阻, 设检测的麦克偏置电流为 Imic, 驻极体麦克偏置电压为 Mic— bias, 驻 极体麦克中二极管的导通电压为 Vf; Further, the earphone type identification module includes a series current detecting circuit and a bias resistor, wherein the detected microphone bias current is Imic, the electret microphone bias voltage is Mic-bias, and the diode of the electret microphone is guided. The pass voltage is Vf;
假设初始时, 选择开关模块将耳机插座的第三引脚和第四引脚分别连 接到麦克接口和地, 默认与 OMTP标准 4脚耳机适配, 所述控制模块根据 麦克偏置电流对插入电子设备耳机插座的耳机类设备进行识别, 包括以下 几种情况: Suppose initially, the selection switch module connects the third pin and the fourth pin of the earphone socket to the microphone interface and the ground respectively, and is matched with the OMTP standard 4-pin earphone by default, and the control module inserts the electronic device according to the microphone bias current pair. The headset device of the device's headphone jack is identified, including the following:
当电流检测电路检测到 100微安 Imic < 500微安时 ,识别出插入的是 OMTP标准 4脚耳机插头;
当电流检测电路检测到 0.9( Mic— bias-Vf )/R5 < Imic < l.K Mic— bias-Vf ) /R5时, 识别出插入的是北美常用标准 4脚耳机插头, R5为偏置电阻; 当电流检测电路检测到 Imic > 1.1 ( Mic— bias-Vf) /R5时, 识别出插入 的是三脚耳机类设备。 When the current detection circuit detects 100 μA Imic < 500 μA, it recognizes that the OMTP standard 4-pin headphone plug is inserted; When the current detecting circuit detects 0.9 ( Mic - bias - Vf ) / R5 < Imic < lK Mic - bias - Vf ) / R5 , it recognizes that the plug is a standard 4 - foot headphone plug in North America, and R5 is a bias resistor; When the current detection circuit detects Imic > 1.1 (Mic-bias-Vf) / R5, it recognizes that the three-legged headphone device is inserted.
进一步的, 所述控制模块根据麦克偏置电流控制选择开关模块将电子 设备耳机插座的第三引脚和第四引脚分别连接到电子设备的麦克接口和地 或者分别连接到电子设备的地和麦克, 并为所述耳机类设备配置相应音频 通道, 具体包括: Further, the control module connects the third pin and the fourth pin of the earphone socket of the electronic device to the microphone interface and the ground of the electronic device or to the ground of the electronic device respectively according to the microphone bias current control selection switch module. The microphone, and configuring the corresponding audio channel for the earphone device, specifically includes:
当 100微安 Imic < 500微安时,控制模块按照 OMTP标准为插入的所 述耳机类设备配置音频通道; When 100 microamps Imic < 500 microamps, the control module configures an audio channel for the inserted headset device in accordance with the OMTP standard;
当 0.9 ( Mic— bias-Vf ) /R5 < Imic < 1.1 ( Mic— bias-Vf ) /R5 时, 控制模 块控制选择开关模块将电子设备耳机插座的第三引脚和第四引脚分别连接 到电子设备的地和麦克接口, 再按照北美常用标准为插入的所述耳机类设 备配置音频通道; When 0.9 ( Mic−bias-Vf ) /R5 < Imic < 1.1 ( Mic− bias-Vf ) /R5, the control module controls the selection switch module to connect the third pin and the fourth pin of the earphone socket of the electronic device respectively The ground and the mic interface of the electronic device, and then the audio channel is configured for the inserted earphone device according to the commonly used standard in North America;
当电流检测电路检测到 Imic > 1.1 ( Mic— bias-Vf) /R5时, 控制模块为 插入的三脚耳机类设备配置音频通道。 When the current detection circuit detects Imic > 1.1 (Mic-bias-Vf) /R5, the control module configures an audio channel for the inserted three-pin headphones type device.
进一步的, 所述耳机类型识别模块包括串联的电流检测电路和偏置电 阻, 设检测的麦克偏置电流为 Imic, 驻极体麦克偏置电压为 Mic— bias, 驻 极体麦克中二极管的导通电压为 Vf; Further, the earphone type identification module includes a series current detecting circuit and a bias resistor, wherein the detected microphone bias current is Imic, the electret microphone bias voltage is Mic-bias, and the diode of the electret microphone is guided. The pass voltage is Vf;
假设初始时, 选择开关模块将耳机插座的第三引脚和第四引脚分别连 接到地和麦克接口, 默认与北美常用标准 4脚耳机适配, 所述控制模块根 据麦克偏置电流对插入电子设备耳机插座的耳机类设备进行识别, 包括以 下几种情况: Assume initially that the selection switch module connects the third pin and the fourth pin of the headphone jack to the ground and microphone interfaces respectively. The default is to adapt to the North American standard 4-pin headphone, and the control module is inserted according to the microphone bias current pair. The earphone-type device of the earphone socket of the electronic device is identified, including the following situations:
当电流检测电路检测到 100微安 Imic < 500微安时 ,识别出插入的是 北美常用标准 4脚耳机插头;
当电流检测电路检测到 0.9( Mic— bias-Vf )/R5 < Imic < l.K Mic— bias-Vf ) /R5时, 识别出插入的是 OMTP标准 4脚耳机插头, R5为偏置电阻; When the current detection circuit detects 100 microamps of Imic < 500 microamps, it recognizes that the plug-in is a commonly used standard 4-pin headphone plug in North America; When the current detecting circuit detects 0.9 ( Mic - bias - Vf ) / R5 < Imic < lK Mic - bias - Vf ) / R5, it recognizes that the OMTP standard 4-pin headphone plug is inserted, and R5 is a bias resistor;
当电流检测电路检测到 Imic > 1.1 ( Mic— bias-Vf) /R5时, 识别出插入 的是三脚耳机类设备。 When the current detection circuit detects Imic > 1.1 (Mic-bias-Vf) /R5, it recognizes that the three-legged headphone device is inserted.
进一步的, 所述控制模块根据麦克偏置电流控制选择开关模块将电子 设备耳机插座的第三引脚和第四引脚分别连接到电子设备的麦克接口和地 或者分别连接到电子设备的地和麦克, 并为所述耳机类设备配置相应音频 通道, 具体包括: Further, the control module connects the third pin and the fourth pin of the earphone socket of the electronic device to the microphone interface and the ground of the electronic device or to the ground of the electronic device respectively according to the microphone bias current control selection switch module. The microphone, and configuring the corresponding audio channel for the earphone device, specifically includes:
当 100微安 Imic 500微安时,控制模块按照北美常用标准为插入的 所述耳机类设备配置音频通道; When the 100 microamp Imic is 500 microamps, the control module configures an audio channel for the inserted headset device according to the commonly used standards in North America;
当 0.9 ( Mic— bias-Vf ) /R5 < Imic < 1.1 ( Mic— bias-Vf ) /R5 时, 控制模 块控制选择开关模块将电子设备耳机插座的第三引脚和第四引脚分别连接 到电子设备的麦克接口和地, 再按照 OMTP标准为插入的所述耳机类设备 配置音频通道; When 0.9 ( Mic−bias-Vf ) /R5 < Imic < 1.1 ( Mic− bias-Vf ) /R5, the control module controls the selection switch module to connect the third pin and the fourth pin of the earphone socket of the electronic device respectively a microphone interface and a ground of the electronic device, and then configuring an audio channel for the inserted earphone device according to the OMTP standard;
当电流检测电路检测到 Imic > 1.1 ( Mic— bias-Vf) /R5时, 控制模块为 插入的三脚耳机类设备配置音频通道。 When the current detection circuit detects Imic > 1.1 (Mic-bias-Vf) /R5, the control module configures an audio channel for the inserted three-pin headphones type device.
进一步的, 该电路还包括三脚耳机类设备识别模块; Further, the circuit further includes a three-legged earphone type device identification module;
三脚耳机类设备识别模块包括串联的第二电阻和第四电阻, 工作电压 The three-legged earphone type device identification module includes a second resistor and a fourth resistor connected in series, and an operating voltage
VDD依次通过第二电阻和第四电阻接地, 电子设备耳机插座的第一引脚或 者第二引脚, 以及控制模块的第二控制端均连接到第二电阻和第四电阻之 间, 控制模块的第二控制端输入为低电平的最高电压是 VDD x ( R4//Re ) / ( R2+ R4//Re ), R2为第二电阻, R4为第四电阻, Re为 3脚耳机扬声器 阻抗; VDD is grounded through the second resistor and the fourth resistor in turn, the first pin or the second pin of the earphone socket of the electronic device, and the second control end of the control module are connected between the second resistor and the fourth resistor, the control module The highest voltage of the second control terminal input is VDD x ( R4//Re ) / ( R2+ R4//Re ), R2 is the second resistor, R4 is the fourth resistor, and Re is the 3-pin headphone speaker impedance. ;
所述当电流检测电路检测到 Imic > 1.1 ( Mic— bias-Vf ) /R5时, 控制模 块为插入的三脚耳机类设备配置音频通道, 具体包括:
当控制模块的第二控制端输入为低电平时, 插入电子设备耳机插座的 为 3脚耳机, 控制模块为插入的 3脚耳机配置音频通道; When the current detecting circuit detects Imic > 1.1 (Mic-bias-Vf) /R5, the control module configures an audio channel for the inserted three-leg headphone device, which specifically includes: When the second control terminal of the control module is input low, the earphone socket of the electronic device is a 3-pin earphone, and the control module configures an audio channel for the inserted 3-pin earphone;
当控制模块的第二控制端输入为高电平时, 插入电子设备耳机插座的 为 3脚音频线, 控制模块为插入的 3脚音频线配置音频通道。 When the second control terminal of the control module is input high, the 3-pin audio cable is inserted into the earphone socket of the electronic device, and the control module configures the audio channel for the inserted 3-pin audio cable.
进一步的, 该电路还包括设备插入检测模块; Further, the circuit further includes a device insertion detection module;
设备插入检测模块包括第一电阻和第三电阻,工作电压 VDD通过第一 电阻连接到电子设备耳机插座的第六引脚, 电子设备耳机插座的第一引脚 通过第三电阻接地, 控制模块的第一控制端与耳机插座的第六引脚相连, 第一控制端输入为低电平的最高电压是¥00 1 3/ ( 1 1+1 3 ), R1为第一电 阻, R3为第三电阻; The device insertion detecting module includes a first resistor and a third resistor, and the working voltage VDD is connected to the sixth pin of the earphone socket of the electronic device through the first resistor, and the first pin of the earphone socket of the electronic device is grounded through the third resistor, and the control module is The first control end is connected to the sixth pin of the earphone socket, and the highest voltage input to the first control terminal is low level is ¥00 1 3/ (1 1+1 3 ), R1 is the first resistance, and R3 is the third Resistance
当没有设备插入电子设备耳机插座时, 电子设备耳机插座的第一引脚 和第六引脚相接触, 控制模块的第一控制端为低电平; When no device is inserted into the earphone socket of the electronic device, the first pin and the sixth pin of the earphone socket of the electronic device are in contact, and the first control end of the control module is at a low level;
当有设备插入电子设备耳机插座时, 电子设备耳机插座的第一引脚和 第六引脚分离, 控制模块的第一控制端为高电平。 When a device is inserted into the earphone socket of the electronic device, the first pin and the sixth pin of the earphone socket of the electronic device are separated, and the first control end of the control module is at a high level.
进一步的, 该电路还包括设备插入检测模块; Further, the circuit further includes a device insertion detection module;
设备插入检测模块包括第一电阻和第三电阻,工作电压 VDD通过第一 电阻连接到电子设备耳机插座的第五引脚, 电子设备耳机插座的第二引脚 通过第三电阻接地, 控制模块的第一控制端与耳机插座的第五引脚相连, 第一控制端输入为低电平的最高电压是¥00 1 3/ ( 1 1+1 3 ), R1为第一电 阻, R3为第三电阻; The device insertion detecting module includes a first resistor and a third resistor, the working voltage VDD is connected to the fifth pin of the earphone socket of the electronic device through the first resistor, and the second pin of the earphone socket of the electronic device is grounded through the third resistor, and the control module is The first control terminal is connected to the fifth pin of the earphone socket, and the highest voltage input to the first control terminal is low level is ¥00 1 3/ (1 1+1 3 ), R1 is the first resistance, and R3 is the third Resistance
当没有设备插入电子设备耳机插座时, 电子设备耳机插座的第二引脚 和第五引脚相接触, 控制模块的第一控制端为低电平; When no device is inserted into the earphone socket of the electronic device, the second pin and the fifth pin of the earphone socket of the electronic device are in contact, and the first control end of the control module is at a low level;
当有设备插入电子设备耳机插座时, 电子设备耳机插座的第二引脚和 第五引脚分离, 控制模块的第一控制端为高电平。 When a device is inserted into the earphone socket of the electronic device, the second pin and the fifth pin of the earphone socket of the electronic device are separated, and the first control end of the control module is at a high level.
进一步的, 当控制模块通过设备插入检测模块测得第一控制端口为高
电平时, 开启驻极体麦克偏置电压, 输入到耳机类型识别模块。 Further, when the control module detects that the first control port is high through the device insertion detection module At the level, the electret microphone bias voltage is turned on and input to the earphone type recognition module.
进一步的, 所述控制模块釆用高通公司的 QSC6155芯片, 所述电流检 测电路釆用高通公司的 PM8028 芯片, 或者, 所述控制模块和所述电流检 测电路釆用一块高通公司的 QSC6055芯片; Further, the control module uses Qualcomm's QSC6155 chip, the current detecting circuit uses Qualcomm's PM8028 chip, or the control module and the current detecting circuit use a Qualcomm QSC6055 chip;
所述选择开关模块为一可控双刀双掷开关。 The selector switch module is a controllable double pole double throw switch.
釆用上述技术方案, 本发明至少具有下列优点: With the above technical solution, the present invention has at least the following advantages:
本发明所述耳机接口自适应电路, 安装在一个支持 4脚耳机插座的电 子设备中, 控制模块通过耳机类型识别模块检测到的麦克偏置电流区分插 入的是 OMTP标准 4脚耳机、 北美常用标准 4脚耳机还是 3脚立体声耳机 或 3脚音频线, 控制模块通过控制选择开关模块可以使电子设备耳机插座 与麦克接口和地信号的连接关系互换, 这样可以使所述耳机接口自适应电 路能根据插入的 OMTP接口耳机或者北美常用接口耳机进行切换, 同时支 持这两种耳机。 将本发明所述电路应用于手机等电子设备中, 能够使手机 等设备的耳机接口自动识别耳机类型, 并根据识别的耳机类型自动调整接 口电路和音频通道来适应所插入的耳机类设备。 附图说明 The earphone interface adaptive circuit of the invention is installed in an electronic device supporting a 4-pin headphone socket, and the control module detects the microphone bias current detected by the earphone type identification module to be inserted into the OMTP standard 4-pin earphone, and the commonly used standard in North America. The 4-pin earphone is also a 3-pin stereo earphone or a 3-pin audio cable. The control module can exchange the connection relationship between the electronic device earphone socket and the microphone interface and the ground signal by controlling the selection switch module, so that the earphone interface adaptive circuit can be Switch between the inserted OMTP interface headset or the North American common interface headset, and support both headsets. The circuit of the present invention is applied to an electronic device such as a mobile phone, so that the earphone interface of the device such as a mobile phone can automatically recognize the earphone type, and automatically adjust the interface circuit and the audio channel according to the recognized earphone type to adapt to the inserted earphone type device. DRAWINGS
图 1 为 3脚 3.5mm耳机连接器和 4脚 3.5mm耳机连接器结构的对比示 意图; Figure 1 shows a comparison of the structure of a 3-pin 3.5mm headphone connector and a 4-pin 3.5mm headphone connector;
图 2 为 3脚立体声耳机电路图; Figure 2 is a circuit diagram of a 3-pin stereo headset;
图 3 为 OMTP引脚定义 4脚立体声耳机电路图; Figure 3 shows the OMTP pin definition 4-pin stereo headphone circuit diagram;
图 4 为北美常用引脚定义 4脚立体声耳机电路图; Figure 4 shows the four-pin stereo headphone circuit diagram for common pin definitions in North America;
图 5 为驻极体麦克内部电路图; Figure 5 is an internal circuit diagram of the electret microphone;
图 6 为双公头立体声音频线结构示意图; Figure 6 is a schematic diagram of the structure of a dual male stereo audio line;
图 7 为本发明第一实施例所述耳机接口自适应电路示意图; 7 is a schematic diagram of an adaptive circuit of a headphone interface according to a first embodiment of the present invention;
图 8 ( a )、 ( b )分别为本发明设备插入检测模块在设备拔出和插入耳机
插座两种情况的等效电路图; Figure 8 (a), (b) respectively, the device insertion detection module of the present invention is unplugged and inserted into the device The equivalent circuit diagram of the two cases of the socket;
图 9 ( a )、 ( b )分别为本发明三脚耳机类设备识别模块在 3脚音频线和 3脚耳机插入耳机插座时的等效电路图; 9( a ) and ( b ) are respectively equivalent circuit diagrams of the three-legged earphone type device identification module when the 3-pin audio cable and the 3-pin earphone are inserted into the earphone socket;
图 10 为本发明第二实施例所述耳机接口自适应电路示意图; FIG. 10 is a schematic diagram of an adaptive circuit of a headphone interface according to a second embodiment of the present invention; FIG.
图 11 为本发明第三实施例所述耳机接口自适应电路示意图; 11 is a schematic diagram of an adaptive circuit of a headphone interface according to a third embodiment of the present invention;
图 12 为本发明第四实施例所述耳机接口自适应电路示意图。 具体实施方式 下结合附图及较佳实施例, 对本发明进行详细说明如后。 FIG. 12 is a schematic diagram of an adaptive circuit of a headphone interface according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments.
首先介绍一下本发明解决技术问题的思路, 将本发明所述耳机接口自 适应电路安装在一个支持 4脚耳机插座的耳机或类似电子设备中, 先用设 备插入检测模块通过机械检测的方式来检测是否有设备插入。 如果检测到 有设备插入, 则打开电子设备中的驻极体麦克偏置电压并检测麦克偏置电 流, 麦克正向偏置、 麦克反向偏置和麦克对地短路这三种情况下, 麦克偏 置电流是不一样的,通过麦克偏置电流可以区分插入的是 OMTP接口耳机、 北美常用接口耳机还是 3脚立体声耳机或 3脚音频线。 又引入一可控双刀 双掷开关, 可以控制电子设备耳机插座与电子设备的麦克接口和地信号的 连接方式进行互换, 这样可以使所述耳机接口自适应电路能根据插入的 OMTP接口耳机或者北美常用接口耳机进行切换, 同时支持这两种耳机。 Firstly, the invention solves the technical problem. The earphone interface adaptive circuit of the present invention is installed in a headphone or similar electronic device supporting a 4-pin earphone socket, and is first detected by means of mechanical detection by using a device insertion detecting module. Is there a device plugged in? If a device insertion is detected, the electret microphone bias voltage in the electronic device is turned on and the microphone bias current is detected, and the microphone is forward biased, the microphone reverse biased, and the microphone is shorted to the ground. The bias current is different. The microphone bias current can be used to distinguish whether the OMTP interface earphone, the North American common interface earphone or the 3-pin stereo earphone or the 3-pin audio cable. A controllable double-pole double-throw switch is further introduced, which can control the connection between the earphone socket of the electronic device and the microphone interface and the ground signal of the electronic device, so that the earphone interface adaptive circuit can be based on the inserted OMTP interface earphone. Or switch between the commonly used interface headphones in North America, and support both types of headphones.
由于 3脚耳机或 3脚音频线插入后, 相当于将电子设备上的麦克接口 和地短路, 所以无法通过麦克偏置电流来区分。 因为 3脚耳机和 3脚音频 线的差别是 3脚耳机左右声道因为有喇叭的关系, 对地的阻抗一般为 32欧 姆。 而 3脚音频线左右声道的对地阻抗, 在 3脚音频线另一头没有接到汽 车音响或音频功放之类设备时是无穷大的, 即使 3脚音频线另一头已经接 到汽车音响或音频功放之类设备时, 由于这些设备输入端有隔直电容的关
系, 其直流阻抗也是无穷大。 所以又设计一个三脚耳机类设备识别模块来 判断左声道或右声道对地电阻的大小来判断插入的设备是 3脚耳机还是 3 脚音频线。 Since the 3-pin earphone or the 3-pin audio cable is inserted, it is equivalent to short-circuiting the microphone interface and the ground on the electronic device, so it cannot be distinguished by the microphone bias current. Because the difference between the 3-pin earphone and the 3-pin audio cable is that the left-right channel of the 3-pin earphone has a relationship with the ground, and the impedance to the ground is generally 32 ohms. The impedance of the left and right channels of the 3-pin audio cable is infinite when the other end of the 3-pin audio cable is not connected to a car audio or audio amplifier, even if the other end of the 3-pin audio cable has been connected to the car audio or audio. For devices such as amplifiers, because of the blocking capacitance of the input terminals of these devices The DC impedance is also infinite. Therefore, a three-legged headphone device identification module is designed to determine the magnitude of the left or right channel ground resistance to determine whether the inserted device is a 3-pin earphone or a 3-pin audio cable.
本说明书介绍的方法基于应用于手机的 3.5mm耳机类设备, 但并不限 于手机和 3.5mm耳机。 The method described in this manual is based on a 3.5mm headphone device for mobile phones, but is not limited to mobile phones and 3.5mm headphones.
本发明第一实施例, 图 7是本实施例中的耳机接口自适应电路图, 该 耳机接口自适应电路包括: 设备插入检测模块、 控制模块, 耳机类型识别 模块、 选择开关模块和三脚耳机类设备识别模块, 控制模块即手机或类似 电子设备的主控制器, 可以釆用高通公司的 QSC6155芯片。 A first embodiment of the present invention, FIG. 7 is an adaptive circuit diagram of a headphone interface in the embodiment, the headphone interface adaptive circuit includes: a device insertion detection module, a control module, a headphone type identification module, a selection switch module, and a three-leg headphone device. The identification module, the main controller of the mobile phone or similar electronic device, can use Qualcomm's QSC6155 chip.
耳机插座 J1为常见的 4脚耳机插座,耳机插座 J1内部除了和插头对应 的第一引脚 1〜第四引脚 4引脚外还有第五引脚 5和第六引脚 6, 通常耳机 插座 J1的第一引脚 1通过第一隔直电容 C1连接到主控制器上的左声道接 口, 耳机插座 J1的第二引脚 2通过第二隔直电容 C2连接到主控制器上的 右声道接口。 The headphone jack J1 is a common 4-pin headphone jack. The headphone jack J1 has a fifth pin 5 and a sixth pin 6 in addition to the first pin 1 to the fourth pin 4 pin corresponding to the plug, usually the earphone The first pin 1 of the socket J1 is connected to the left channel interface on the main controller through the first DC blocking capacitor C1, and the second pin 2 of the headphone socket J1 is connected to the main controller through the second DC blocking capacitor C2. Right channel interface.
当 4脚耳机插头从耳机插座 J1拔出的时候, 第一引脚 1和第六引脚 6 内部是接触的, 第二引脚 2和第五引脚 5也是接触的; 当 4脚耳机插头插 入耳机插座 J1后, 第一引脚 1和第六引脚 6内部是分离的, 第二引脚 2和 第五引脚 5也是分离的。 When the 4-pin headphone plug is unplugged from the headphone jack J1, the first pin 1 and the sixth pin 6 are in contact internally, and the second pin 2 and the fifth pin 5 are also in contact; when the 4-pin headphone plug is After the headphone jack J1 is inserted, the first pin 1 and the sixth pin 6 are internally separated, and the second pin 5 and the fifth pin 5 are also separated.
设备插入检测模块配合耳机插座 J1即可实现耳机插拔检测功能, 设备 插入检测模块包括第一电阻 R1和第三电阻 R3 ,第三电阻 R3远小于第一电 阻 R1 , 工作电压 VDD通过第一电阻 R1连接到耳机插座 J1的第六引脚 6, 耳机插座 J1的第一引脚 1通过第三电阻 R3接地, 控制模块的第一控制端 H DET1与耳机插座 J1的第六引脚 6相连。 The device insertion detection module cooperates with the earphone socket J1 to implement the headphone plug detection function. The device insertion detection module includes a first resistor R1 and a third resistor R3. The third resistor R3 is much smaller than the first resistor R1, and the working voltage VDD passes through the first resistor. R1 is connected to the sixth pin 6 of the headphone jack J1, the first pin 1 of the headphone jack J1 is grounded through the third resistor R3, and the first control end H DET1 of the control module is connected to the sixth pin 6 of the headphone jack J1.
当没有任何设备插入时, 第一引脚 1和第六引脚 6内部接触, 又因为 第三电阻 R3远小于第一电阻 R1 , 所以控制模块的第一控制端 H DET1是
低电平, 等效电路如图 8 ( a ) 所示。 当有设备插入后, 第一引脚 1和第六 引脚 6内部分离, 所以控制模块的第一控制端 H— DET1是高电平, 等效电 路如图 8 ( b )所示。 手机或类似电子设备的主控制器通过识别第一控制端 H DET1 的电平高低即可判断是否有设备插入。 当主控制器通过设备插入 检测模块测得第一控制端口 H— DET1 为高电平时, 开启麦克偏置电压 Mic— bias电源, 输入到耳机类型识别模块。 When no device is inserted, the first pin 1 and the sixth pin 6 are internally contacted, and since the third resistor R3 is much smaller than the first resistor R1, the first control terminal H DET1 of the control module is Low level, the equivalent circuit is shown in Figure 8 (a). When a device is inserted, the first pin 1 and the sixth pin 6 are internally separated, so the first control terminal H_DET1 of the control module is at a high level, and the equivalent circuit is as shown in FIG. 8(b). The main controller of the mobile phone or similar electronic device can determine whether a device is inserted by identifying the level of the first control terminal H DET1. When the main controller detects that the first control port H_DET1 is high through the device insertion detection module, the microphone bias voltage Mic-bias power is turned on and input to the earphone type identification module.
图 7和图 8中第一电阻 R1和第三电阻 R3的取值标准主要可以考虑两 点: The values of the first resistor R1 and the third resistor R3 in Figures 7 and 8 can mainly consider two points:
1 )第一电阻 R1和第三电阻 R3都比较大一些, 一般为 10K欧姆以上, 这样电路工作电流会较小一些; 1) The first resistor R1 and the third resistor R3 are both larger, generally 10K ohms or more, so that the circuit operating current will be smaller;
2 )保证主控制器第一控制端 H— DET1 的输入为低电平的最高电压是 raz)x_^_,即主控制器第一控制端 H DET1能将 rai)x~^_识别为低电 RI + R3 - RI + R3 2) Ensure that the highest voltage of the input of the first control terminal H_DET1 of the main controller is raz)x _^_, that is, the first control terminal H DET1 of the main controller can recognize rai)x~^_ as Low battery RI + R3 - RI + R3
平。 这是一种利用在耳机插入和拔出两种情况下, 插座簧片的位置不同来 实现插拔检测的电路。 level. This is a circuit that realizes plug-and-pull detection by using different positions of the socket reeds in both the case of inserting and unplugging the earphone.
耳机类型识别模块包括图 7中串联的电流检测电路 D2和偏置电阻 R5。 电流检测电路 D2釆用高通公司的 PM8028芯片, 偏置电阻 R5用于给驻极 体麦克内的场效应管漏极提供合适的电压。 Mic— bias 是手机等类似电子设 备提供给驻极体麦克的偏置电压, 第三隔直电容 C3 是主控制器麦克端口 The earphone type identification module includes a current detecting circuit D2 and a biasing resistor R5 connected in series in FIG. The current detection circuit D2 uses Qualcomm's PM8028 chip, and the bias resistor R5 is used to supply the appropriate voltage to the FET drain in the electret microphone. Mic-bias is the bias voltage provided by the mobile device and other similar electronic devices to the electret microphone. The third DC blocking capacitor C3 is the main controller microphone port.
Mic的隔直电容。 偏置电阻 R5的取值一般和驻极体麦克的输出阻抗接近, 耳机常用的麦克输出阻抗为 2.2K欧姆,所以图中偏置电阻 R5也设置为 2.2K 欧姆。 麦克偏置电压 Mic— bias的取值和麦克的特性也有关, 耳机常用的麦 克偏置电压 Mic— bias为 2V。 Mic's DC blocking capacitor. The value of the bias resistor R5 is generally close to the output impedance of the electret microphone. The commonly used microphone output impedance of the earphone is 2.2K ohms, so the bias resistor R5 is also set to 2.2K ohms. The value of the microphone bias voltage Mic-bias is also related to the characteristics of the microphone. The commonly used microphone bias voltage Mic-bias is 2V.
OMTP标准 3.5mm 4脚耳机和北美常用标准 3.5mm 4脚耳机在引脚 定义上, 其麦克和地正好相反, 而对于 3.5mm 3脚立体声耳机, 没有麦克 引脚, 其地引脚正好覆盖 4脚耳机的麦克和地两个引脚。 这里引入一个可
控双刀双掷开关芯片 D 1和电流检测电路 D2来实现耳机类型的检测 , 电流 检测电路在很多手机的模拟基带部分已经集成, 一般不需要额外设计, 如 在高通公司的 QSC6055平台和 QSC6155+PM8028平台都集成有电流检测 电路, 用于检测麦克偏置电流。 The OMTP standard 3.5mm 4-pin headphones and the commonly used standard 3.5mm 4-pin headphones in North America are on the pin definition. The microphone and the ground are exactly the opposite. For the 3.5mm 3-pin stereo headphones, there is no microphone pin, and the ground pin just covers 4 The mic and ground pins of the footphone. Introduce a here Control double-pole double-throw switch chip D 1 and current detection circuit D2 to realize the detection of earphone type. The current detection circuit has been integrated in the analog baseband part of many mobile phones, generally no additional design is required, such as Qualcomm's QSC6055 platform and QSC6155+. The PM8028 platform integrates a current-sense circuit to detect the mic bias current.
在图 7中, 双刀双掷开关默认状态是耳机插座 J1的第四引脚 4接地, 第三引脚 3脚接麦克接口 Mic , 相当于默认是 OMTP标准耳机定义。 当前 面的耳机插拔检测电路检测到有设备插入后 ,电流检测电路 D2检测麦克偏 置电源的电流。 如果插入的是 OMTP标准 4脚耳机, 此时麦克是正向偏置 的, 麦克正向偏置电流和麦克风内部的专用场效应管的特性有关, 场效应 管栅极电压确定的情况下, 场效应管呈恒流源, 基本与外部偏置电压 Mic— bias和偏置电阻 R5无关,一般为 100~350微安,最大不超过 500微安, 将电流检测电路 D2检测到的偏置电流记为 Imic, 如果检测到 100微安 Imic 500微安, 可以判断为插入的是 OMTP标准 4脚耳机, 主控制器按 照 OMTP标准为插入的耳机类设备配置音频通道, 通话时, 发送方向走耳 机上的麦克, 接收方向走耳机上的喇叭。 设置完后, 手机或者类似电子设 备可以做其他处理。 In Figure 7, the default state of the double-pole double-throw switch is the fourth pin 4 of the headphone jack J1, and the third pin is connected to the microphone interface Mic. The default is the OMTP standard headphone definition. When the current headphone plug detecting circuit detects that a device is inserted, the current detecting circuit D2 detects the current of the microphone biasing the power source. If the OMTP standard 4-pin earphone is inserted, the microphone is forward-biased, and the forward bias current of the microphone is related to the characteristics of the dedicated FET inside the microphone. The field effect transistor gate voltage is determined in the case of field effect. The tube is a constant current source, basically independent of the external bias voltage Mic-bias and bias resistor R5, generally 100~350 microamperes, the maximum does not exceed 500 microamperes, and the bias current detected by the current detecting circuit D2 is recorded as Imic, if 100 microamps of Imic 500 microamps are detected, it can be judged that the OMTP standard 4-pin earphone is inserted. The main controller configures the audio channel for the inserted earphone-type device according to the OMTP standard. When calling, the sending direction is on the earphone. Mike, the receiver is in the direction of the speaker on the headset. After the setup, the phone or similar electronic device can do other processing.
如果插入的是北美常用标准 4脚耳机, 相当于耳机麦克是反向偏置的, 那么此时的麦克偏置电流为因为稳压二级管 (图 3、 图 4的 D1 , 常选型号 为 1N4737等) 的缘故, 所以麦克偏置电流 Imic « ( Mic— bias-Vf ) /R5 , 其 中 Vf是稳压二极管的正向导通电压,常温下正向导通电流 If约为 1mA时, 为 0.7V左右。 考虑偏置电压 Mic— bias、 二极管的导通电压 Vf和偏置电阻 R5都有一定的误差, 这里麦克反向偏置电流的范围放宽 ± 10%, 即当电流 电测电路检测到 0.9 ( Mic_bias-0.7 ) /R5 < Imic < 1.1 ( Mic_bias-0.7 ) /R5 时, 说明此时耳机麦克是反向偏置的, 主控制器需要通过第三控制端 Ctrl 控制双刀双掷开关 D1进行切换, 将两个开关切换到另一边, 即将耳机插座
Jl的第四引脚 4接麦克接口 Mic, 第三引脚 3脚接地, 使麦克处于正向偏 置, 然后按照北美常用标准为插入的耳机类设备配置音频通道。 If you insert a commonly used standard 4-pin earphone in North America, which is equivalent to the reverse bias of the earphone microphone, then the microphone bias current is due to the Zener diode (Figure 3, Figure 4, D1, the frequently selected model is 1N4737, etc., so the microphone bias current Imic « ( Mic - bias-Vf ) / R5 , where Vf is the forward voltage of the Zener diode, and the normal conduction current If at room temperature is about 1mA, 0.7V about. Considering the bias voltage Mic-bias, the diode's turn-on voltage Vf, and the bias resistor R5, there is a certain error, where the range of the mic reverse bias current is relaxed by ± 10%, that is, when the current electrical circuit detects 0.9 (Mic_bias -0.7 ) /R5 < Imic < 1.1 ( Mic_bias-0.7 ) /R5, indicating that the headset microphone is reverse biased at this time, the main controller needs to control the double-pole double-throw switch D1 to switch through the third control terminal Ctrl. Switch the two switches to the other side, that is, the headphone jack The fourth pin 4 of Jl is connected to the microphone interface Mic, the third pin 3 is grounded, the microphone is forward biased, and then the audio channel is configured for the inserted earphone type device according to the commonly used standard in North America.
优选的, 偏置电阻 R5=2.2K 欧姆, 偏置电压 Mic— bias=2V, 则 (0.9 Mic_bias-0.7 ) /R5=0.9 ( 2.0-0.7 ) /2.2k=532微安, 这个值比麦克正向偏置电 压的最大值 500微安要大。 Preferably, the bias resistor R5=2.2K ohm, the bias voltage Mic−bias=2V, then (0.9 Mic_bias-0.7) /R5=0.9 (2.0-0.7) /2.2k=532 microamperes, this value is better than the microphone The maximum value of the bias voltage is 500 μA.
如果插入的是 3脚耳机或者 3脚音频线, 则耳机插座 J1的第三引脚 3 和第四引脚 4短路, 麦克偏置电流 Imic=Mic— bias/R5 , 因为 Mic— bias要求 在 2V左右, 一般选 1.8~2.2V, Vf- 0.7V, 所以能保证 1.1 ( Mic_bias-0.7 ) /R5 < Mic_bias/R5 , 电流范围可以适当放宽, 即当电流检测电路 D2检测到 Imic > 1.1 ( Mic_bias-0.7 ) /R5 , 就可以认为插入的是 3脚耳机或者 3脚音频 线。 但是此时还是无法区别插入的到底是 3脚耳机还是 3脚音频线。 由于 此时通常 Imic大于 750微安, 处于短路电流范围内, 会影响待机时间, 所 以最好将 Mic— bias电源关闭。 If a 3-pin earphone or a 3-pin audio cable is inserted, the third pin 3 and the fourth pin 4 of the headphone jack J1 are short-circuited, and the microphone bias current Imic=Mic_bias/R5 is because the Mic-bias is required at 2V. Left and right, generally choose 1.8~2.2V, Vf-0.7V, so it can guarantee 1.1 (Mic_bias-0.7) /R5 < Mic_bias/R5 , the current range can be relaxed appropriately, that is, when the current detection circuit D2 detects Imic > 1.1 ( Mic_bias- 0.7 ) /R5 , you can think of a 3-pin or 3-pin audio cable. However, it is still impossible to distinguish whether the 3-pin or 3-pin audio cable is inserted. Since the Imic is usually greater than 750 μA at this time and is in the short-circuit current range, it will affect the standby time, so it is better to turn off the Mic-bias power supply.
如果 Imic不在上面的几个范围内,那么插入的是一种无法识别的设备。 在手机上弹出窗口提示用户无法识别插入的设备。 接下去手机可以做其他 处理。 If Imic is not in the above range, then an unrecognized device is inserted. A pop-up window on the phone prompts the user not to recognize the inserted device. Next, the phone can do other processing.
图 7中, 由第二电阻 R2和第四电阻 R4构成的三脚耳机类设备识别模 块可以用于区分是 3脚耳机还是 3脚音频线,第二电阻 R2远小于第四电阻 R4。 In Fig. 7, the three-pin earphone type device recognition module composed of the second resistor R2 and the fourth resistor R4 can be used to distinguish whether it is a 3-pin earphone or a 3-pin audio cable, and the second resistor R2 is much smaller than the fourth resistor R4.
如果插入的是 3脚耳机或者 3脚音频线, 即图 2或图 6中 3脚耳机或 者 3脚音频线插头的第三引脚 3和图 7中耳机插座 J1的第三引脚 3和第四 引脚 4同时接触,3脚耳机或者 3脚音频线插头的第二引脚 2和耳机插座 J1 的第二引脚 2接触, 3脚耳机或者 3脚音频线插头的第一引脚 1和耳机插座 J1的第一引脚 1接触。 If a 3-pin earphone or a 3-pin audio cable is inserted, that is, the third pin 3 of the 3-pin earphone or the 3-pin audio cable plug of FIG. 2 or FIG. 6 and the third pin 3 and the third pin of the headphone jack J1 of FIG. Four-pin 4 simultaneous contact, the second pin 2 of the 3-pin audio or 3-pin audio cable plug and the second pin 2 of the headphone jack J1, the first pin 1 of the 3-pin audio or 3-pin audio cable plug The first pin 1 of the headphone jack J1 is in contact.
工作电压 VDD依次通过第二电阻 R2和第四电阻 R4接地, 耳机插座
Jl的第二引脚 2以及主控制器的第二控制端 H— DET2均连接到第二电阻 R2 和第四电阻 R4之间。 The working voltage VDD is grounded through the second resistor R2 and the fourth resistor R4 in sequence, the earphone socket The second pin 2 of J1 and the second control terminal H_DET2 of the main controller are both connected between the second resistor R2 and the fourth resistor R4.
当插入的为 3脚音频线时, 其右声道对地电阻都为无穷大, 这种情况 下, 主控制器第二控制端 H—DET2部分等效电路为图 9 ( a )所示, 由于第 二电阻 R2远小于第四电阻 R4, 所以主控制器第二控制端 H— DET2是高电 平。 When the 3-pin audio cable is inserted, the right channel-to-ground resistance is infinite. In this case, the equivalent circuit of the second control terminal H-DET2 of the main controller is as shown in Fig. 9(a), because The second resistor R2 is much smaller than the fourth resistor R4, so the second control terminal H_DET2 of the main controller is at a high level.
当插入的为 3脚耳机时, 相当于耳机插座 J1的第二引脚 2和地之间又 接了一个阻值为 32欧姆的电阻, 即 3脚耳机扬声器阻抗 Re,此时三脚耳机 类设备识别模块与第二控制端 H— DET2连接的部分等效电路如图 9 ( b )所 示, 3脚耳机扬声器阻抗 Re和第四电阻 R4并联电阻值远小于第二电阻 R2 , 此时第二控制端 H— DET2为低电平。 When the 3-pin earphone is inserted, a resistor equivalent to 32 ohms is connected between the second pin 2 of the headphone jack J1 and the ground, that is, the 3-pin headphone speaker impedance Re, and the three-leg headphone type device at this time The partial equivalent circuit of the identification module connected to the second control terminal H_DET2 is as shown in FIG. 9(b), and the parallel resistance of the 3-pin earphone speaker impedance Re and the fourth resistor R4 is much smaller than the second resistance R2, and the second Control terminal H - DET2 is low.
所以, 可以根据第二控制端 H— DET2的高低电平来区分是 3脚耳机还 是 3脚音频线插入。 对于第二电阻 R2和第四电阻 R4的取值, 只要保证主 控制器的第二控制端 H— DET2输入为低电平的最高电压是 VDD ( R4//Re ) / ( R2+ R4//Re ), 凡高于这个数值的都输入高电平, 包括未插入任何设备时 以及插入 3脚音频线时,第二控制端输入电平均介于 VDD ( R4//Re )/( R2+ R4//Re )和 VDD x ( R4 ) / ( R2+ R4 )之间, R4//Re为第四电阻和 3脚耳 机扬声器阻抗 Re的并联阻值。 优选的, 第二电阻 R2=47K欧姆, 第四电阻 R4= 180K欧姆即可满足要求。 Therefore, according to the high and low levels of the second control terminal H_DET2, it can be distinguished whether the 3-pin earphone or the 3-pin audio cable is inserted. For the values of the second resistor R2 and the fourth resistor R4, the highest voltage that ensures that the second control terminal H_DET2 of the main controller is low is VDD ( R4//Re ) / ( R2+ R4//Re ), where all values above this value are input high, including when no device is plugged in and when the 3-pin audio line is plugged in, the second control input is averaged between VDD ( R4//Re )/( R2+ R4// Between Re) and VDD x ( R4 ) / ( R2+ R4 ), R4//Re is the parallel resistance of the fourth resistor and the 3-pin headphone speaker impedance Re. Preferably, the second resistor R2 = 47K ohms, and the fourth resistor R4 = 180K ohms can meet the requirements.
当控制模块的第二控制端 H— DET2输入为低电平时, 插入电子设备耳 机插座的为 3脚耳机, 控制模块为插入的 3脚耳机配置音频通道, 使手机 等类似电子设备在通话过程中发送时用手机上的麦克, 接收时用耳机接口。 接下去可以做手机的其他处理。 When the second control terminal H_DET2 of the control module is input low, the 3-pin earphone is inserted into the earphone socket of the electronic device, and the control module configures an audio channel for the inserted 3-pin earphone, so that the mobile phone and the like are in the process of talking. Use the microphone on the phone when sending, and use the headphone jack when receiving. Next, you can do other processing of the phone.
当控制模块的第二控制端 H— DET2输入为高电平时, 插入电子设备耳 机插座的为 3脚音频线, 控制模块需要为插入的 3脚音频线配置音频通道,
使手机等类似电子设备在通话过程中发送时用手机上的麦克, 接收时用耳 机接口, 同时设置音频参数为免提模式, 声音通过音频线接到其他大音量 设备后, 通话时出现嘯叫自激。 接下去做手机的其他处理。 When the second control terminal H_DET2 of the control module is input to a high level, the 3-pin audio cable is inserted into the earphone socket of the electronic device, and the control module needs to configure an audio channel for the inserted 3-pin audio cable. Make the mobile phone and other similar electronic devices use the microphone on the mobile phone during the call, use the earphone interface when receiving, and set the audio parameters to the hands-free mode. After the sound is connected to other large volume devices through the audio cable, the whistle occurs during the call. Self-excited. Then do other processing of the phone.
图 7中, 左声道耳机输出接口 H— L和右声道耳机输出接口 H— R, 以及 和麦克接口 Mic—起, 接到耳机类电子设备主控制器的音频接口中。 In Fig. 7, the left channel headphone output interface H-L and the right channel headphone output interface H-R, and the microphone interface Mic are connected to the audio interface of the headphone type electronic device main controller.
本发明第二实施例, 本实施例与第一实施例大致相同, 区别在于: The second embodiment of the present invention is substantially the same as the first embodiment, and the difference is:
1 )控制模块与电流检测电路所釆用的芯片; 1) a chip used by the control module and the current detecting circuit;
2 殳备插入检测模块以及三脚耳机类设备识别模块与耳机插座 J1中各 引脚的连接方式; 2 The connection detection module and the three-pin headphone type device identification module are connected with the pins of the headphone socket J1;
3 )双刀双掷开关 D1的初始默认状态。 3) Double-pole double-throw switch The initial default state of D1.
图 10是本实施例中的耳机接口自适应电路图, 该耳机接口自适应电路 包括: 设备插入检测模块、 控制模块, 耳机类型识别模块、 选择开关模块 和三脚耳机类设备识别模块, 控制模块即手机或类似电子设备的主控制器, 可以釆用高通公司的 QSC6055芯片。 10 is an adaptive circuit diagram of the earphone interface in the embodiment, the earphone interface adaptive circuit includes: a device insertion detection module, a control module, a headphone type identification module, a selection switch module, and a three-leg headphone device identification module, and the control module is a mobile phone. Or the main controller of similar electronic equipment, you can use Qualcomm's QSC6055 chip.
设备插入检测模块配合耳机插座 J1即可实现耳机插拔检测功能, 设备 插入检测模块包括第一电阻 R1和第三电阻 R3 ,第三电阻 R3远小于第一电 阻 R1 , 工作电压 VDD通过第一电阻 R1连接到耳机插座 J1的第五引脚 5 , 耳机插座 J1的第二引脚 2通过第三电阻 R3接地, 控制模块的第一控制端 H DET1与耳机插座 J1的第五引脚 5相连。 The device insertion detection module cooperates with the earphone socket J1 to implement the headphone plug detection function. The device insertion detection module includes a first resistor R1 and a third resistor R3. The third resistor R3 is much smaller than the first resistor R1, and the working voltage VDD passes through the first resistor. R1 is connected to the fifth pin 5 of the headphone jack J1, the second pin 2 of the headphone jack J1 is grounded through the third resistor R3, and the first control end H DET1 of the control module is connected to the fifth pin 5 of the headphone jack J1.
当没有任何设备插入时, 第二引脚 2和第五引脚 5 内部接触, 又因为 第三电阻 R3远小于第一电阻 R1 , 所以控制模块的第一控制端 H— DET1是 低电平, 等效电路如图 8 ) 所示。 当有设备插入后, 第二引脚 2和第五 引脚 5内部分离, 所以控制模块的第一控制端 H— DET1是高电平, 等效电 路如图 8 ( b )所示。 手机或类似电子设备的主控制器通过识别第一控制端 H DET1 的电平高低即可判断是否有设备插入。 当主控制器通过设备插入
检测模块测得第一控制端口 H— DET1 为高电平时, 开启麦克偏置电压 Mic— bias , 输入到耳机类型识别模块。 When no device is inserted, the second pin 2 and the fifth pin 5 are internally contacted, and since the third resistor R3 is much smaller than the first resistor R1, the first control terminal H_DET1 of the control module is low. The equivalent circuit is shown in Figure 8). When a device is inserted, the second pin 2 and the fifth pin 5 are internally separated, so the first control terminal H_DET1 of the control module is at a high level, and the equivalent circuit is as shown in FIG. 8(b). The main controller of the mobile phone or similar electronic device can determine whether a device is inserted by identifying the level of the first control terminal H DET1. When the main controller is plugged in through the device When the detection module detects that the first control port H_DET1 is at a high level, the microphone bias voltage Mic_bias is turned on and input to the earphone type identification module.
图 10和图 8中第一电阻 R1和第三电阻 R3的取值标准主要可以考虑两 点: The values of the first resistor R1 and the third resistor R3 in Fig. 10 and Fig. 8 can mainly consider two points:
1 )第一电阻 R1和第三电阻 R3都比较大一些, 一般为 10K欧姆以上, 这样电路工作电流会较小一些; 1) The first resistor R1 and the third resistor R3 are both larger, generally 10K ohms or more, so that the circuit operating current will be smaller;
2 )保证主控制器第一控制端 H— DET1 的输入为低电平的最高电压是 raz)x_^_,即主控制器第一控制端 H DET1能将 rai)x~^_识别为低电 RI + R3 - RI + R3 2) Ensure that the highest voltage of the input of the first control terminal H_DET1 of the main controller is raz)x _^_, that is, the first control terminal H DET1 of the main controller can recognize rai)x~^_ as Low battery RI + R3 - RI + R3
平。 这是一种利用在耳机插入和拔出两种情况下, 插座簧片的位置不同来 实现插拔检测的电路。 level. This is a circuit that realizes plug-and-pull detection by using different positions of the socket reeds in both the case of inserting and unplugging the earphone.
耳机类型识别模块包括图 10 中串联的电流检测电路 D2 和偏置电阻 The earphone type identification module includes the current detecting circuit D2 and the bias resistor connected in series in FIG.
R5。本实施例中, 电流检测电路 D2的功能也由作为主控制器的高通公司的R5. In this embodiment, the function of the current detecting circuit D2 is also performed by Qualcomm as the main controller.
QSC6055芯片来完成,偏置电阻 R5用于给驻极体麦克内的场效应管漏极提 供合适的电压。 Mic— bias 是手机等类似电子设备提供给驻极体麦克的偏置 电压, 第三隔直电容 C3是主控制器麦克端口 Mic的隔直电容。 偏置电阻The QSC6055 chip is used to complete the bias resistor R5 to provide the appropriate voltage to the FET drain in the electret microphone. Mic-bias is the bias voltage provided by the mobile device and other similar electronic devices to the electret microphone. The third DC blocking capacitor C3 is the DC blocking capacitor of the main controller microphone port Mic. Bias resistor
R5的取值一般和驻极体麦克的输出阻抗接近, 耳机常用的麦克输出阻抗为The value of R5 is generally close to the output impedance of the electret microphone. The commonly used microphone output impedance of the earphone is
2.2K 欧姆, 所以图中偏置电阻 R5 也设置为 2.2K 欧姆。 麦克偏置电压2.2K ohms, so the bias resistor R5 is also set to 2.2K ohms. Mike bias voltage
Mic— bias 的取值和麦克的特性也有关, 耳机常用的麦克偏置电压 Mic— bias 为 2V。 The value of Mic-bias is also related to the characteristics of the microphone. The commonly used microphone bias voltage Mic-bias is 2V.
OMTP标准 3.5mm 4脚耳机和北美常用标准 3.5mm 4脚耳机在引脚 定义上, 其麦克和地正好相反, 而对于 3.5mm 3脚立体声耳机, 没有麦克 引脚, 其地引脚正好覆盖 4脚耳机的麦克和地两个引脚。 这里引入一个可 控双刀双掷开关芯片 D 1和电流检测电路 D2来实现耳机类型的检测 , 电流 检测电路在很多手机的模拟基带部分已经集成, 一般不需要额外设计, 如 在高通公司的 QSC6055平台和 QSC6155+PM8028平台都集成有电流检测
电路, 用于检测麦克偏置电流。 The OMTP standard 3.5mm 4-pin headphones and the commonly used standard 3.5mm 4-pin headphones in North America are on the pin definition. The microphone and the ground are exactly the opposite. For the 3.5mm 3-pin stereo headphones, there is no microphone pin, and the ground pin just covers 4 The mic and ground pins of the footphone. Here, a controllable double-pole double-throw switch chip D 1 and a current detecting circuit D2 are introduced to realize the detection of the earphone type. The current detecting circuit is integrated in the analog baseband portion of many mobile phones, and generally does not require an additional design, such as QSC6055 in Qualcomm. Both the platform and the QSC6155+PM8028 platform integrate current sensing A circuit that detects the mic bias current.
在图 10中,双刀双掷开关默认状态是耳机插座 J1的第四引脚 4接麦克 接口 Mic, 第三引脚 3脚接地, 相当于默认是北美常用标准耳机定义。 当前 面的耳机插拔检测电路检测到有设备插入后 ,电流检测电路 D2检测麦克偏 置电源的电流。 如果插入的是北美常用标准 4脚耳机, 此时麦克是正向偏 置的, 麦克正向偏置电流和麦克风内部的专用场效应管的特性有关, 场效 应管栅极电压确定的情况下, 场效应管呈恒流源, 基本和外部偏置电压 Mic— bias和偏置电阻 R5无关,一般为 100~350微安,最大不超过 500微安, 将电流检测电路 D2检测到的偏置电流记为 Imic, 如果检测到 100微安 Imic 500微安, 可以判断为插入的是北美常用标准 4脚耳机, 主控制器按 照北美常用标准为插入的耳机类设备配置音频通道, 通话时, 发送方向走 耳机上的麦克, 接收方向走耳机上的喇叭。 设置完后, 手机或者类似电子 设备可以做其他处理。 In Figure 10, the default state of the double-pole double-throw switch is the fourth pin of the headphone jack J1. 4 is connected to the microphone interface Mic, and the third pin is grounded to the ground. The default is the standard definition of the standard headphones in North America. When the current headphone plug detecting circuit detects that a device is inserted, the current detecting circuit D2 detects the current of the microphone biasing the power source. If you insert a commonly used standard 4-pin earphone in North America, the microphone is forward-biased. The forward bias current of the microphone is related to the characteristics of the dedicated FET inside the microphone. When the FET gate voltage is determined, the field The effect tube is a constant current source, and the basic and external bias voltages Mic-bias and bias resistor R5 are independent, generally 100~350 microamperes, and the maximum is less than 500 microamperes, and the bias current detected by the current detecting circuit D2 is recorded. For Imic, if 100 microamps of Imic 500 microamps are detected, it can be judged that it is a commonly used standard 4-pin earphone in North America. The main controller configures an audio channel for the inserted earphone-type device according to the commonly used standards in North America. The microphone on the earphone receives the direction of the speaker on the earphone. After the setup, the phone or similar electronic device can do other processing.
如果插入的是 OMTP标准 4脚耳机, 相当于耳机麦克是反向偏置的, 那么此时的麦克偏置电流为因为有场效应管栅极和源极之间二级管的缘 故, 所以麦克偏置电流 Imic - ( Mic— bias-Vf ) /R5 , 其中 Vf是二极管的导 通电压, 为 0.7V左右。 考虑偏置电压 Mic— bias、 二极管的导通电压 Vf和 偏置电阻 R5都有一定的误差, 这里麦克反向偏置电流的范围放宽 ± 10%, 即当 电流电测电路检测到 0.9 ( Mic_bias-0.7 ) /R5 < Imic < 1.1 ( Mic_bias-0.7 ) /R5 时, 说明此时耳机麦克是反向偏置的, 主控制器需要 通过第三控制端 Ctrl控制双刀双掷开关 D1进行切换,将两个开关切换到另 一边, 即将耳机插座 J1的第四引脚 4接地, 第三引脚 3脚接麦克接口 Mic, 使麦克处于正向偏置, 然后按照 OMTP标准为插入的耳机类设备配置音频 通道。 If the OMTP standard 4-pin earphone is inserted, which is equivalent to the reverse bias of the earphone microphone, then the microphone bias current is due to the diode between the gate and the source of the FET, so the microphone The bias current Imic - ( Mic - bias - Vf ) / R5 , where Vf is the turn-on voltage of the diode and is about 0.7V. Considering the bias voltage Mic-bias, the diode's turn-on voltage Vf, and the bias resistor R5, there is a certain error, where the range of the mic reverse bias current is relaxed by ± 10%, that is, when the current electrical circuit detects 0.9 (Mic_bias -0.7 ) /R5 < Imic < 1.1 ( Mic_bias-0.7 ) /R5, indicating that the headset microphone is reverse biased at this time, the main controller needs to control the double-pole double-throw switch D1 to switch through the third control terminal Ctrl. Switch the two switches to the other side, that is, the fourth pin 4 of the headphone jack J1 is grounded, the third pin 3 is connected to the microphone interface Mic, the microphone is forward biased, and then the earphone type device is inserted according to the OMTP standard. Configure the audio channel.
优选的, 偏置电阻 R5=2.2K 欧姆, 偏置电压 Mic bias=2V , 则 0.9
( Mic_bias-0.7 ) /R5=0.9 ( 2.0-0.7 ) /2.2k=532微安, 这个值比麦克正向偏置 电压的最大值 500微安要大。 Preferably, the bias resistor R5=2.2K ohms, the bias voltage Mic bias=2V, then 0.9 (Mic_bias-0.7) /R5=0.9 ( 2.0-0.7 ) /2.2k=532 μA, which is larger than the maximum value of 500 μA of the forward bias voltage of the microphone.
如果插入的是 3脚耳机或者 3脚音频线, 则耳机插座 J1的第三引脚 3 和第四引脚 4短路, 麦克偏置电流 Imic=Mic— bias/R5 , 因为 Mic— bias要求 在 2V左右, 一般选 1.8~2.2V, Vf- 0.7V, 所以能保证 1.1 ( Mic— bias-0.7 ) /R5 ) < Mic_bias/R5 , 电流范围可以适当放宽, 即当电流检测电路 D2检测 到 Imic > 1.1 ( Mic— bias-0.7 ) /R5 , 就可以认为插入的是 3脚耳机或者 3脚 音频线。 但是此时还是无法区别插入的到底是 3脚耳机还是 3脚音频线。 由于此时通常 Imic大于 750微安,处于短路电流范围内,会影响待机时间, 所以最好将 Mic— bias电源关闭。 If a 3-pin earphone or a 3-pin audio cable is inserted, the third pin 3 and the fourth pin 4 of the headphone jack J1 are short-circuited, and the microphone bias current Imic=Mic_bias/R5 is because the Mic-bias is required at 2V. Left and right, generally choose 1.8~2.2V, Vf-0.7V, so it can guarantee 1.1 (Mic-bias-0.7) /R5) < Mic_bias/R5 , the current range can be relaxed appropriately, that is, when the current detection circuit D2 detects Imic > 1.1 (Mic-bias-0.7) /R5, you can think of the insertion of a 3-pin earphone or a 3-pin audio cable. However, it is still impossible to distinguish whether the 3-pin or 3-pin audio cable is inserted. Since Imic is usually greater than 750 μA at this time and is in the short-circuit current range, it will affect the standby time, so it is best to turn off the Mic-bias power supply.
如果 Imic不在上面的几个范围内,那么插入的是一种无法识别的设备。 在手机上弹出窗口提示用户无法识别插入的设备。 接下去手机可以做其他 处理。 If Imic is not in the above range, then an unrecognized device is inserted. A pop-up window on the phone prompts the user not to recognize the inserted device. Next, the phone can do other processing.
图 10中,由第二电阻 R2和第四电阻 R4构成的三脚耳机类设备识别模 块可以用于区分是 3脚耳机还是 3脚音频线,第二电阻 R2远小于第四电阻 R4。 In Fig. 10, the three-leg headphone type device recognition module composed of the second resistor R2 and the fourth resistor R4 can be used to distinguish whether it is a 3-pin earphone or a 3-pin audio cable, and the second resistor R2 is much smaller than the fourth resistor R4.
工作电压 VDD依次通过第二电阻 R2和第四电阻 R4接地, 耳机插座 J1的第一引脚 1以及主控制器的第二控制端 H— DET2均连接到第二电阻 R2 和第四电阻 R4之间。 The working voltage VDD is grounded through the second resistor R2 and the fourth resistor R4 in turn, and the first pin 1 of the headphone jack J1 and the second control end H_DET2 of the main controller are connected to the second resistor R2 and the fourth resistor R4. between.
当插入的为 3脚音频线时, 其右声道对地电阻都为无穷大, 这种情况 下, 主控制器第二控制端 H—DET2部分等效电路为图 9 ( a )所示, 由于第 二电阻 R2远小于第四电阻 R4 , 所以主控制器第二控制端 H— DET2是高电 平。 When the 3-pin audio cable is inserted, the right channel-to-ground resistance is infinite. In this case, the equivalent circuit of the second control terminal H-DET2 of the main controller is as shown in Fig. 9(a), because The second resistor R2 is much smaller than the fourth resistor R4, so the second control terminal H_DET2 of the main controller is at a high level.
当插入的为 3脚耳机时, 相当于耳机插座 J1的第二引脚 2和地之间又 接了一个阻值为 32欧姆的电阻, 即 3脚耳机扬声器阻抗 Re,此时三脚耳机
类设备识别模块与第二控制端 H— DET2连接的部分等效电路如图 9 ( b )所 示, 3脚耳机扬声器阻抗 Re和第四电阻 R4并联电阻值远小于第二电阻 R2 , 此时第二控制端 H— DET2为低电平。 When the 3-pin earphone is inserted, a resistor equivalent to 32 ohms is connected between the second pin 2 of the headphone jack J1 and the ground, that is, the 3-pin earphone speaker impedance Re, at this time, the three-legged earphone The partial equivalent circuit of the class device identification module and the second control terminal H-DET2 is as shown in FIG. 9(b), and the parallel resistance value of the 3-pin earphone speaker impedance Re and the fourth resistor R4 is much smaller than the second resistance R2. The second control terminal H_DET2 is at a low level.
所以, 可以根据第二控制端 H— DET2的高低电平来区分是 3脚耳机还 是 3脚音频线插入。 对于第二电阻 R2和第四电阻 R4的取值, 只要保证主 控制器的第二控制端 H— DET2输入为低电平的最高电压是 VDD ( R4//Re ) / ( R2+ R4//Re ), 凡高于这个数值的都输入高电平, 包括未插入任何设备时 以及插入 3脚音频线时,第二控制端输入电平均介于 VDD ( R4//Re )/( R2+ R4//Re )和 VDD ( R4 ) / ( R2+ R4 )之间。 优选的 , 第二电阻 R2=47K欧 姆, 第四电阻 R4=180K欧姆即可满足要求。 Therefore, according to the high and low levels of the second control terminal H_DET2, it can be distinguished whether the 3-pin earphone or the 3-pin audio cable is inserted. For the values of the second resistor R2 and the fourth resistor R4, the highest voltage that ensures that the second control terminal H_DET2 of the main controller is low is VDD ( R4//Re ) / ( R2+ R4//Re ), where all values above this value are input high, including when no device is plugged in and when the 3-pin audio line is plugged in, the second control input is averaged between VDD ( R4//Re )/( R2+ R4// Re ) and VDD ( R4 ) / ( R2+ R4 ). Preferably, the second resistor R2 = 47K ohms, and the fourth resistor R4 = 180K ohms can meet the requirements.
当控制模块的第二控制端 H— DET2输入为低电平时, 插入电子设备耳 机插座的为 3脚耳机, 控制模块为插入的 3脚耳机配置音频通道, 使手机 等类似电子设备在通话过程中发送时用手机上的麦克, 接收时用耳机接口。 接下去可以做手机的其他处理。 When the second control terminal H_DET2 of the control module is input low, the 3-pin earphone is inserted into the earphone socket of the electronic device, and the control module configures an audio channel for the inserted 3-pin earphone, so that the mobile phone and the like are in the process of talking. Use the microphone on the phone when sending, and use the headphone jack when receiving. Next, you can do other processing of the phone.
当控制模块的第二控制端 H— DET2输入为高电平时, 插入电子设备耳 机插座的为 3脚音频线, 控制模块需要为插入的 3脚音频线配置音频通道, 使手机等类似电子设备在通话过程中发送时用手机上的麦克, 接收时用耳 机接口, 同时设置音频参数为免提模式, 声音通过音频线接到其他大音量 设备后, 通话时出现嘯叫自激。 接下去做手机的其他处理。 When the second control terminal H_DET2 of the control module is input to a high level, the 3-pin audio cable is inserted into the earphone socket of the electronic device, and the control module needs to configure an audio channel for the inserted 3-pin audio cable, so that the mobile phone and the like are in the electronic device. During the call, the microphone on the mobile phone is used for sending, and the earphone interface is used for receiving. At the same time, the audio parameter is set to the hands-free mode. After the sound is connected to other large volume devices through the audio cable, the whistling self-excitation occurs during the call. Then do other processing of the phone.
本发明第三实施例, 本实施例与第一实施例大致相同, 区别在于: 本 实施例的耳机接口自适应电路不包括设备插入检测模块, 如图 11所示, 该 耳机接口自适应电路仅包括: 控制模块、 耳机类型识别模块、 选择开关模 块和三脚耳机类设备识别模块。 本实施例需要长时间开启麦克偏置电压 Mic bias, 一旦有设备插入耳机插座 J1 , 就能开始检测麦克偏置电流, 缺点 是比较耗电, 会导致手机的待机时间缩短。
本发明第四实施例, 本实施例与第一实施例大致相同, 区别在于: 本 实施例的耳机接口自适应电路不包括三脚耳机类设备识别模块, 如图 12所 示, 该耳机接口自适应电路仅包括: 设备插入检测模块、 控制模块、 耳机 类型识别模块和选择开关模块。 本实施例在通过耳机类型识别模块识别出 OMTP 标准的耳机、 北美常用标准的耳机以及三脚耳机类设备后, 无法进 一步区分出三脚耳机类设备是 3脚耳机还是 3脚音频线, 因此, 本实施例 所述耳机接口自适应电路只适用于仅需区分 4脚的 OMTP标准的耳机和北 美常用标准的耳机的情况。 The third embodiment of the present invention is substantially the same as the first embodiment. The difference is that the earphone interface adaptive circuit of the embodiment does not include the device insertion detecting module. As shown in FIG. 11, the earphone interface adaptive circuit only Including: control module, earphone type identification module, selection switch module and three-leg headphone type device identification module. In this embodiment, the microphone bias voltage Mic bias needs to be turned on for a long time. Once a device is inserted into the earphone socket J1, the microphone bias current can be detected. The disadvantage is that the power consumption is relatively high, which may cause the standby time of the mobile phone to be shortened. The fourth embodiment of the present invention is substantially the same as the first embodiment. The difference is that the headset interface adaptive circuit of the embodiment does not include a three-legged headset device identification module. As shown in FIG. 12, the headset interface is adaptive. The circuit only includes: a device insertion detection module, a control module, a headphone type identification module, and a selection switch module. In this embodiment, after the earphone type identification module recognizes the OMTP standard earphone, the North American common standard earphone, and the three-leg earphone type device, it is impossible to further distinguish whether the three-legged earphone type device is a 3-pin earphone or a 3-pin audio cable. Therefore, the present implementation The headphone interface adaptive circuit described in the example is only applicable to the case of only the 4-pin OMTP standard earphone and the North American standard standard earphone.
本发明所述耳机接口自适应电路, 安装在一个支持 4脚耳机插座的电 子设备中, 控制模块通过电流检测电路检测到的麦克偏置电流区分插入的 是 OMTP标准 4脚耳机、 北美常用标准 4脚耳机还是 3脚立体声耳机或 3 脚音频线, 控制模块通过控制选择开关模块可以使电子设备耳机插座与麦 克接口和地信号的连接关系互换, 这样可以使所述耳机接口自适应电路能 根据插入的 OMTP接口耳机或者北美常用接口耳机进行切换, 同时支持这 两种耳机。 将本发明所述电路应用于手机等电子设备中, 能够使手机等设 备的耳机接口可以自动识别耳机类型, 并根据识别的耳机类型自动调整接 口电路和音频通道来适应所插入的耳机类设备。 The earphone interface adaptive circuit of the invention is installed in an electronic device supporting a 4-pin headphone jack, and the control module detects the microphone bias current detected by the current detecting circuit to be inserted into the OMTP standard 4-pin earphone, and the North American common standard 4 The footphone is also a 3-pin stereo earphone or a 3-pin audio cable. The control module can exchange the connection relationship between the electronic device earphone socket and the microphone interface and the ground signal by controlling the selection switch module, so that the earphone interface adaptive circuit can be The inserted OMTP interface headset or the North American common interface headset is switched, and both headsets are supported. The circuit of the present invention is applied to an electronic device such as a mobile phone, so that the earphone interface of the device such as a mobile phone can automatically recognize the type of the earphone, and automatically adjust the interface circuit and the audio channel according to the recognized type of the earphone to adapt to the inserted earphone type device.
通过具体实施方式的说明, 应当可对本发明为达成预定目的所釆取的 技术手段及功效得以更加深入且具体的了解, 然而所附图示仅是提供参考 与说明之用, 并非用来对本发明加以限制。
The technical means and functions of the present invention for achieving the intended purpose can be more deeply and specifically understood by the description of the specific embodiments. However, the accompanying drawings are only for the purpose of reference and description, and are not intended to be Limit it.
Claims
1、 一种耳机接口自适应电路, 其特征在于, 安装在一个支持四脚耳机 插座的电子设备中, 该电路包括: 控制模块, 耳机类型识别模块和选择开 关模块, 其中, A headphone interface adaptive circuit, which is characterized in that, in an electronic device supporting a four-pin earphone socket, the circuit comprises: a control module, a headphone type identification module and a selection switch module, wherein
耳机类型识别模块与电子设备的麦克接口相连, 用于检测插入电子设 备耳机插座的耳机类设备的麦克偏置电流, 并发送给控制模块; The earphone type identification module is connected to the microphone interface of the electronic device, and is configured to detect a microphone bias current of the earphone device inserted into the earphone socket of the electronic device, and send the signal to the control module;
控制模块根据麦克偏置电流对插入电子设备耳机插座的耳机类设备进 行识别, 并控制选择开关模块将电子设备耳机插座的第三引脚和第四引脚 分别连接到电子设备的麦克接口和地、 或者分别连接到电子设备的地和麦 克接口, 为所述耳机类设备配置相应音频通道。 The control module identifies the earphone type device inserted into the earphone socket of the electronic device according to the microphone bias current, and controls the selection switch module to connect the third pin and the fourth pin of the earphone socket of the electronic device to the microphone interface and the ground of the electronic device respectively Or respectively connected to the ground and the microphone interface of the electronic device, and configure corresponding audio channels for the earphone type device.
2、 根据权利要求 1所述耳机接口自适应电路, 其特征在于, 所述耳机 类型识别模块包括串联的电流检测电路和偏置电阻, 设检测的麦克偏置电 流为 Imic, 驻极体麦克偏置电压为 Mic— bias, 驻极体麦克中二极管的导通 电压为 Vf; 2. The headphone interface adaptive circuit according to claim 1, wherein the earphone type identification module comprises a series current detecting circuit and a bias resistor, and the detected microphone bias current is Imic, the electret microphone bias The set voltage is Mic-bias, and the turn-on voltage of the diode in the electret microphone is Vf;
假设初始选择开关模块将耳机插座的第三引脚和第四引脚分别连接到 麦克接口和地时, 默认与 OMTP标准四脚耳机适配, 所述控制模块根据麦 克偏置电流对插入电子设备耳机插座的耳机类设备进行识别, 为: Assuming that the initial selection switch module connects the third pin and the fourth pin of the earphone socket to the microphone interface and the ground respectively, the default is matched with the OMTP standard four-legged earphone, and the control module inserts the electronic device according to the microphone bias current pair. The earphone-type device of the headphone jack is identified as:
当电流检测电路检测到 100微安 Imic < 500微安时 ,识别出插入的是 OMTP标准四脚耳机插头; When the current detection circuit detects 100 microamps Imic < 500 microamps, it is recognized that the OMTP standard four-pin earphone plug is inserted;
当电流检测电路检测到 0.9( Mic— bias-Vf )/R5 < Imic < l.K Mic— bias-Vf ) /R5时, 识别出插入的是北美常用标准四脚耳机插头, R5为偏置电阻; 当电流检测电路检测到 Imic > 1.1 ( Mic— bias-Vf) /R5时, 识别出插入 的是三脚耳机类设备。 When the current detecting circuit detects 0.9 ( Mic - bias - Vf ) / R5 < Imic < lK Mic - bias - Vf ) / R5 , it recognizes that the plug is a commonly used standard four-pin headphone plug in North America, and R5 is a bias resistor; When the current detection circuit detects Imic > 1.1 (Mic-bias-Vf) / R5, it recognizes that the three-legged headphone device is inserted.
3、 根据权利要求 2所述耳机接口自适应电路, 其特征在于, 所述控制 模块根据麦克偏置电流控制选择开关模块将电子设备耳机插座的第三引脚 和第四引脚分别连接到电子设备的麦克接口和地或者分别连接到电子设备 的地和麦克, 并为所述耳机类设备配置相应音频通道, 具体包括: The earphone interface adaptive circuit according to claim 2, wherein the control module controls the switch module to select the third pin of the earphone socket of the electronic device according to the microphone bias current And the fourth pin is respectively connected to the mic interface and the ground of the electronic device or the ground and the mic respectively connected to the electronic device, and the corresponding audio channel is configured for the earphone type device, specifically comprising:
当 100微安 Imic < 500微安时,控制模块按照 OMTP标准为插入的所 述耳机类设备配置音频通道; When 100 microamps Imic < 500 microamps, the control module configures an audio channel for the inserted headset device in accordance with the OMTP standard;
当 0.9 ( Mic— bias-Vf ) /R5 < Imic < 1.1 ( Mic— bias-Vf ) /R5 时, 控制模 块控制选择开关模块将电子设备耳机插座的第三引脚和第四引脚分别连接 到电子设备的地和麦克接口, 再按照北美常用标准为插入的所述耳机类设 备配置音频通道; When 0.9 ( Mic−bias-Vf ) /R5 < Imic < 1.1 ( Mic− bias-Vf ) /R5, the control module controls the selection switch module to connect the third pin and the fourth pin of the earphone socket of the electronic device respectively The ground and the mic interface of the electronic device, and then the audio channel is configured for the inserted earphone device according to the commonly used standard in North America;
当电流检测电路检测到 Imic > 1.1 ( Mic— bias-Vf) /R5时, 控制模块为 插入的三脚耳机类设备配置音频通道。 When the current detection circuit detects Imic > 1.1 (Mic-bias-Vf) /R5, the control module configures an audio channel for the inserted three-pin headphones type device.
4、 根据权利要求 1所述耳机接口自适应电路, 其特征在于, 所述耳机 类型识别模块包括串联的电流检测电路和偏置电阻, 设检测的麦克偏置电 流为 Imic, 驻极体麦克偏置电压为 Mic— bias, 驻极体麦克中二极管的导通 电压为 Vf; The earphone interface adaptive circuit according to claim 1, wherein the earphone type identification module comprises a series current detecting circuit and a bias resistor, and the detected microphone bias current is Imic, the electret microphone bias The set voltage is Mic-bias, and the turn-on voltage of the diode in the electret microphone is Vf;
假设初始选择开关模块将耳机插座的第三引脚和第四引脚分别连接到 地和麦克接口, 默认与北美常用标准四脚耳机适配, 所述控制模块根据麦 克偏置电流对插入电子设备耳机插座的耳机类设备进行识别, 为: It is assumed that the initial selection switch module connects the third pin and the fourth pin of the earphone socket to the ground and the microphone interface respectively, and is matched with the commonly used standard four-leg headphones of North America by default, and the control module inserts the electronic device according to the microphone bias current pair. The earphone-type device of the headphone jack is identified as:
当电流检测电路检测到 100微安 Imic < 500微安时 ,识别出插入的是 北美常用标准四脚耳机插头; When the current detection circuit detects 100 microamps Imic < 500 microamps, it recognizes that the plug-in is a standard four-pin headphone plug commonly used in North America;
当电流检测电路检测到 0·9( Mic— bias-Vf )/R5 < Imic < l.K Mic— bias-Vf ) When the current detection circuit detects 0·9 ( Mic — bias – Vf ) / R5 < Imic < l. K Mic — bias-Vf )
/R5时, 识别出插入的是 OMTP标准四脚耳机插头, R5为偏置电阻; /R5, it is recognized that the OMTP standard four-pin headphone plug is inserted, and R5 is a bias resistor;
当电流检测电路检测到 Imic > 1.1 ( Mic— bias-Vf) /R5时, 识别出插入 的是三脚耳机类设备。 When the current detection circuit detects Imic > 1.1 (Mic-bias-Vf) /R5, it recognizes that the three-legged headphone device is inserted.
5、 根据权利要求 4所述耳机接口自适应电路, 其特征在于, 所述控制 模块根据麦克偏置电流控制选择开关模块将电子设备耳机插座的第三引脚 和第四引脚分别连接到电子设备的麦克接口和地或者分别连接到电子设备 的地和麦克, 并为所述耳机类设备配置相应音频通道, 具体包括: The earphone interface adaptive circuit according to claim 4, wherein the control module controls the third module of the electronic device earphone socket according to the microphone bias current control selection switch module And the fourth pin is respectively connected to the mic interface and the ground of the electronic device or the ground and the mic respectively connected to the electronic device, and the corresponding audio channel is configured for the earphone type device, specifically comprising:
当 100微安 Imic 500微安时,控制模块按照北美常用标准为插入的 所述耳机类设备配置音频通道; When the 100 microamp Imic is 500 microamps, the control module configures an audio channel for the inserted headset device according to the commonly used standards in North America;
当 0.9 ( Mic— bias-Vf ) /R5 < Imic < 1.1 ( Mic— bias-Vf ) /R5 时, 控制模 块控制选择开关模块将电子设备耳机插座的第三引脚和第四引脚分别连接 到电子设备的麦克接口和地, 再按照 OMTP标准为插入的所述耳机类设备 配置音频通道; When 0.9 ( Mic−bias-Vf ) /R5 < Imic < 1.1 ( Mic− bias-Vf ) /R5, the control module controls the selection switch module to connect the third pin and the fourth pin of the earphone socket of the electronic device respectively a microphone interface and a ground of the electronic device, and then configuring an audio channel for the inserted earphone device according to the OMTP standard;
当电流检测电路检测到 Imic > l. l ( Mic— bias-Vf) /R5时, 控制模块为 插入的三脚耳机类设备配置音频通道。 When the current detection circuit detects Imic > l. l ( Mic - bias - Vf) / R5, the control module configures an audio channel for the inserted three-legged headphone device.
6、 根据权利要求 3或 5所述耳机接口自适应电路, 其特征在于, 该电 路进一步包括三脚耳机类设备识别模块; The headphone interface adaptive circuit according to claim 3 or 5, wherein the circuit further comprises a three-leg headphone type device identification module;
三脚耳机类设备识别模块包括串联的第二电阻和第四电阻, 工作电压 VDD依次通过第二电阻和第四电阻接地, 电子设备耳机插座的第一引脚或 者第二引脚, 以及控制模块的第二控制端均连接到第二电阻和第四电阻之 间, 控制模块的第二控制端输入为低电平的最高电压是 VDD x ( R4//Re ) / ( R2+ R4//Re ), R2为第二电阻, R4为第四电阻, Re为 3脚耳机扬声器阻 抗, R4//Re为第四电阻和 3脚耳机扬声器阻抗 Re的并联阻值; The three-leg headphone type device identification module includes a second resistor and a fourth resistor connected in series, and the working voltage VDD is grounded through the second resistor and the fourth resistor in sequence, the first pin or the second pin of the earphone socket of the electronic device, and the control module The second control terminal is connected between the second resistor and the fourth resistor, and the highest voltage input to the second control terminal of the control module is VDD x ( R4//Re ) / ( R2+ R4//Re ), R2 is the second resistor, R4 is the fourth resistor, Re is the 3-pin headphone speaker impedance, R4//Re is the parallel resistance of the fourth resistor and the 3-pin headphone speaker impedance Re;
所述当电流检测电路检测到 Imic > l. l ( Mic— bias-Vf ) /R5时, 控制模 块为插入的三脚耳机类设备配置音频通道, 具体包括: When the current detecting circuit detects Imic > l. l ( Mic - bias - Vf ) / R5, the control module configures an audio channel for the inserted three-legged earphone device, which specifically includes:
当控制模块的第二控制端输入为低电平时, 插入电子设备耳机插座的 为 3脚耳机, 控制模块为插入的 3脚耳机配置音频通道; When the second control terminal of the control module is input low, the 3-pin earphone plugged into the earphone socket of the electronic device, and the control module configures an audio channel for the inserted 3-pin earphone;
当控制模块的第二控制端输入为高电平时, 插入电子设备耳机插座的 为 3脚音频线, 控制模块为插入的 3脚音频线配置音频通道。 When the second control terminal of the control module is input high, the 3-pin audio cable is inserted into the earphone socket of the electronic device, and the control module configures the audio channel for the inserted 3-pin audio cable.
7、 根据权利要求 1所述耳机接口自适应电路, 其特征在于, 该电路进 一步包括设备插入检测模块; 7. The headphone interface adaptive circuit according to claim 1, wherein the circuit is advanced One step includes a device insertion detection module;
设备插入检测模块包括第一电阻和第三电阻,工作电压 VDD通过第一 电阻连接到电子设备耳机插座的第六引脚, 电子设备耳机插座的第一引脚 通过第三电阻接地, 控制模块的第一控制端与耳机插座的第六引脚相连, 第一控制端输入为低电平的最高电压是¥00 1 3/ ( 1 1+1 3 ), R1为第一电 阻, R3为第三电阻; The device insertion detecting module includes a first resistor and a third resistor, and the working voltage VDD is connected to the sixth pin of the earphone socket of the electronic device through the first resistor, and the first pin of the earphone socket of the electronic device is grounded through the third resistor, and the control module is The first control end is connected to the sixth pin of the earphone socket, and the highest voltage input to the first control terminal is low level is ¥00 1 3/ (1 1+1 3 ), R1 is the first resistance, and R3 is the third Resistance
当没有设备插入电子设备耳机插座时, 电子设备耳机插座的第一引脚 和第六引脚相接触, 控制模块的第一控制端为低电平; When no device is inserted into the earphone socket of the electronic device, the first pin and the sixth pin of the earphone socket of the electronic device are in contact, and the first control end of the control module is at a low level;
当有设备插入电子设备耳机插座时, 电子设备耳机插座的第一引脚和 第六引脚分离, 控制模块的第一控制端为高电平。 When a device is inserted into the earphone socket of the electronic device, the first pin and the sixth pin of the earphone socket of the electronic device are separated, and the first control end of the control module is at a high level.
8、 根据权利要求 1所述耳机接口自适应电路, 其特征在于, 该电路进 一步包括设备插入检测模块; 8. The headphone interface adaptive circuit according to claim 1, wherein the circuit further comprises a device insertion detecting module;
设备插入检测模块包括第一电阻和第三电阻,工作电压 VDD通过第一 电阻连接到电子设备耳机插座的第五引脚, 电子设备耳机插座的第二引脚 通过第三电阻接地, 控制模块的第一控制端与耳机插座的第五引脚相连, 第一控制端输入为低电平的最高电压是¥00 1 3/ ( 1 1+1 3 ), R1为第一电 阻, R3为第三电阻; The device insertion detecting module includes a first resistor and a third resistor, the working voltage VDD is connected to the fifth pin of the earphone socket of the electronic device through the first resistor, and the second pin of the earphone socket of the electronic device is grounded through the third resistor, and the control module is The first control terminal is connected to the fifth pin of the earphone socket, and the highest voltage input to the first control terminal is low level is ¥00 1 3/ (1 1+1 3 ), R1 is the first resistance, and R3 is the third Resistance
当没有设备插入电子设备耳机插座时, 电子设备耳机插座的第二引脚 和第五引脚相接触, 控制模块的第一控制端为低电平; When no device is inserted into the earphone socket of the electronic device, the second pin and the fifth pin of the earphone socket of the electronic device are in contact, and the first control end of the control module is at a low level;
当有设备插入电子设备耳机插座时, 电子设备耳机插座的第二引脚和 第五引脚分离, 控制模块的第一控制端为高电平。 When a device is inserted into the earphone socket of the electronic device, the second pin and the fifth pin of the earphone socket of the electronic device are separated, and the first control end of the control module is at a high level.
9、 根据权利要求 7或 8所述耳机接口自适应电路, 其特征在于, 当控 制模块通过设备插入检测模块测得第一控制端口为高电平时, 开启驻极体 麦克偏置电压, 输入到耳机类型识别模块。 The earphone interface adaptive circuit according to claim 7 or 8, wherein when the control module detects that the first control port is at a high level by the device insertion detecting module, the electret microphone bias voltage is turned on, and the input is Headphone type identification module.
10、 据权利要求 2或 4所述耳机接口自适应电路, 其特征在于, 所述 控制模块釆用高通公司的 QSC6155芯片, 所述电流检测电路釆用高通公司 的 PM8028 芯片, 或者, 所述控制模块和所述电流检测电路釆用一块高通 公司的 QSC6055芯片; 10. The headphone interface adaptive circuit according to claim 2 or 4, wherein The control module uses Qualcomm's QSC6155 chip, the current detecting circuit uses Qualcomm's PM8028 chip, or the control module and the current detecting circuit use a Qualcomm QSC6055 chip;
所述选择开关模块为可控双刀双掷开关。 The selection switch module is a controllable double-pole double-throw switch.
Applications Claiming Priority (2)
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CN201010274094.3A CN102404665B (en) | 2010-09-07 | 2010-09-07 | A kind of earphone interface adaptive circuit |
CN201010274094.3 | 2010-09-07 |
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PCT/CN2011/073199 WO2012031481A1 (en) | 2010-09-07 | 2011-04-22 | Adaptive circuit of earphone interface |
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CN106714030A (en) * | 2015-07-23 | 2017-05-24 | 杭州纳雄科技有限公司 | Earphone circuit |
CN106714030B (en) * | 2015-07-23 | 2022-03-08 | 杭州纳雄科技有限公司 | Earphone circuit |
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