CN1728082A

CN1728082A - Method for raising versatility of earphone interface

Info

Publication number: CN1728082A
Application number: CN 200510028282
Authority: CN
Inventors: 邱亮
Original assignee: BEIHAO COMMUNICATION ELECTRONIC Co Ltd SHANGHAI
Current assignee: BEIHAO COMMUNICATION ELECTRONIC Co Ltd SHANGHAI
Priority date: 2005-07-29
Filing date: 2005-07-29
Publication date: 2006-02-01

Abstract

A method for raising generality of earphone interface includes carrying out identification for earphone type by device according to character that different pin definition on earphone with different electric characteristic can be found when earphone is plugged in device socket, selecting and switching over circuit from interface circuits for providing different interface circuit to different earphone by microprocessor in device according to identified result for supporting more types of earphones by device.

Description

A kind of method that improves versatility of earphone interface

[technical field]

The present invention relates to the earphone interface field, particularly a kind of method that improves versatility of earphone interface.

[background technology]

At present, earphone has become the requisite external equipments of most of portable product such as mobile phone, present most of mobile phone all adopts the method configuration of " steady and reliable " to earphone, be the supporting earphone that a kind of mobile phone of model must use the dedicated version of producer's appointment, earphone that can not compatible other models.Even cause the earphone that plurality of specifications might same producer also must be arranged like this, not only make compatible bad between its product, be unfavorable for the standardized administration produced and externally customize miscellaneous earphone, cannot say for sure to demonstrate,prove product quality and reduce cost of products.When requiring others to exchange with it as the people in some areas, must use local dialect, and can not use other language, this certainly will cause this interchange that significant limitation is arranged, and can not realize effectively linking up.

Simultaneously because the manufacturer of portable product is various, each producer has various product line again, like this for some users, if he has a plurality of mobile phones or other portable equipments, he probably will be furnished with several earphones simultaneously so, and he must know what the use equipment of each earphone is, so bring inconvenience to use.Secondly, the user of now a lot of portable type electronic products especially young man wishes that they have novel design by used product, can embody " personalization ", therefore they wish and can often change the collocation of used product, only can use earphone special to be difficult to satisfy them, will reduce the attractive force of product to a great extent like this for the user for the novelty of product and the demand of " personalization ".

If we study for the used earphone of portable type electronic product, we can find that the earphone of various products can not general reason have two: the kind that at first is earphone interface is different with structure, that is to say between the mechanical dimension of interface has difference, does not match on the mechanical property; Next is that the mechanical dimension of interface is identical, but the definition of the circuit of the pin of earphone interface circuit is different, and for example: 2 pin of certain earphone interface definition are microphone (MIC) input, and 2 pin of another one earphone are defined as voice output.For first kind of situation,, can not exchange mutually with an American of meeting English as a Chinese of meeting Chinese because the restriction of mechanical property is difficult to accomplish the general of earphone; For second kind of situation, on the identical basis of mechanism characteristics, during only owing to circuit design for the difference of pinout cause can not be shared situation under, for domestic consumer is to be difficult to understand, versatility to product also is very unfortunate, and the reason that can not exchange as two Chinese that all say Chinese only is to be the dialect in local separately because they say.

Therefore, need to propose a kind of method that more effectively improves versatility of earphone interface, solve

The deficiencies in the prior art.

[summary of the invention]

The technical problem to be solved in the present invention is to provide a kind of method that improves versatility of earphone interface, the type of select by increasing, commutation circuit being judged the insertion earphone, the circuit of earphone interface is selected to switch, reaching the purpose that interface circuit can compatible a plurality of earphones, thereby improve the versatility of earphone interface.

For solving the problems of the technologies described above, the present invention is achieved in that

A kind of method that improves versatility of earphone interface, insert the earphone jack of equipment when earphone after, cause the pin electrical specification difference of different earphones because the pinout of different earphones is different, according to this characteristics equipment the type of earphone is differentiated, according to differentiating the result, selection commutation circuit in the microprocessor control earphone interface circuit in the equipment provides the distinct interface circuit at different earphones, thereby makes equipment can support multiple earphone.

The invention has the advantages that: the versatility that can effectively increase the earphone interface circuit of portable type electronic product, help user flexibility when making things convenient for production and select used earphone, having solved in the past, product can only use a drawback that earphone special brought.

[description of drawings]

Fig. 1 is a system architecture diagram of the present invention.

Among the figure:

MCU is a microprocessor;

MIC is a microphone;

SPEAK is a sound channel.

Fig. 2 is an electrical block diagram of the present invention.

Among the figure:

J1 is the earphone socket in the interface circuit;

U1 is the two-way analog switch FSA2257 of fairchild company;

U2 is the comparer MAX9705 of MAXIM company;

R2 is a pull-up resistor;

R4, R5 are divider resistances;

C1, C2 are capacitances.

Fig. 3 is the synoptic diagram of the pin number definition of headset plug of the present invention.

Fig. 4 is the Headphone structure synoptic diagram of the first kind of the present invention.

Fig. 5 is the Headphone structure synoptic diagram of the present invention's second type.

[embodiment]

As shown in Figure 1, at the deficiencies in the prior art, the present invention propose a kind of by increase to select, commutation circuit makes the earphone interface can compatible multiple earphone with same mechanical structure, thereby increases the method and the specific implementation circuit thereof of versatility of earphone interface.

This example is that the stereophone of 4pole type is an example with interface plug common in the portable type electronic product, and this interface circuit has been realized the earphone of can compatible two kinds of pinouts different 4pole types.

As shown in Figure 2, J1 is the earphone socket in the interface circuit among Fig. 2, and U1 is the two-way analog switch FSA2257 of fairchild company, and this analog switch is realized the passage handoff functionality; U2 is the comparer MAX9705 of MAXIM company, and the circuit that U2 and pull-up resistor R2 and divider resistance R4, R5 form can realize whether earphone is inserted and the judgement of headset type; Capacitor C 1, C2 are the required capacitances of earphone left and right acoustic channels output sound signal.Power supply VCC is that the operating voltage of system is 3.0V, and power supply MIC_BIAS offers microphone in the earphone as the required bias voltage of its work by resistance R 1, is 3.0V.

Signal MIC_IN is the voice signal of the microphone input system speech processing circuit on the earphone; Signal SPEAK_L is the voice signal that the system voice treatment circuit outputs to the earphone L channel; Signal SPEAK_R is the voice signal that the system voice treatment circuit outputs to the earphone R channel; Signal HP_SELECT is a passage switch-over control signal of being exported to U1 by microprocessor; Signal HP_DETECT is that the earphone that is input to microprocessor inserts detection signal; Signal HP_TYPE is the headset type decision signal of the little processing of input; Signal HOOK_KEY is the telephone receiving button look-at-me of input microprocessor.

1～4 pin of socket J1 in the corresponding earphone interface circuit, the pin number definition of 4pole headset plug as shown in Figure 3.

In this example can compatible two types the 4pole formula earphone that uses shown in Fig. 4 (first kind) and Fig. 5 (second type).

Contrast the interface definition of the earphone of these two types for convenience, we represent the plug interface definition of the first kind and the second type earphone respectively with table 1.

Table 1: the plug interface definition of two types of earphones

	1	2	3	4
	1	2	3	4	Class1	Ground (GND)	Microphone (MIC)	R channel (SPK_R)	L channel (SPK/L)
Type 2	Ground (GND)	L channel (SPK/L)	R channel (SPK_R)	Microphone (MIC)	Class1	Ground (GND)	Microphone (MIC)	R channel (SPK_R)	L channel (SPK/L)

As can be seen from Table 1, all are grounding pin (they all are like this for most of 4pole type earphone) for these two kinds of earphone 1 pin, 3 pin all are R channel output simultaneously; Difference is that MIC input and L channel output are respectively 2,4 pin for Class1, is 4,2 opposite pin for 2 of types.

Referring to all views, introduce the whole workflow of the design's circuit compatibility first kind and two kinds of earphones of second type below:

When 1, not having earphone to insert

This moment, 3 pin owing to interface socket J1 linked to each other with 5 pin, 4 pin link to each other with 6 pin, and 5 pin of J1 are connected to high level by pull-up resistor R2, and little processing this moment is judged does not have earphone to insert, the operating bias voltage MIC_BIAS of MIC is not provided, and the control system speech processing circuit is not worked simultaneously.

Microprocessor is with the passage switch-over control signal HP_SELECT output high level of U1, and promptly 2 pin of J1 are connected to the L channel output of speech processing circuit, and 4 pin are connected to the MIC input.

2, when inserting the earphone of Class1

Because after inserting earphone, 3 pin of J1 and 5 pin separate, 4 pin and 6 pin are separately.Be the R channel output SPEAKER of earphone at this moment between 3 pin of J1 and 1 pin, the typical resistance of earphone SPEAKER is 32 ohm, earphone inserts big resistance pull-up resistor (the tens K ohm) dividing potential drop that detects pin on this resistance and the microprocessor, make 3 pin of J1 become low level, there is earphone to insert thereby microprocessor is judged, the operating bias voltage MIC_BIAS of the MIC of earphone is provided this moment.

Be the L channel output SPEAKER of earphone simultaneously between 4 pin of J1 and 1 pin, therefore 4 pin and the resistance between 1 pin of J1 are 32 ohm, the 3V voltage of this resistance and 1 couple of MIC_BIAS of resistance R carries out dividing potential drop, therefore this moment J1 4 pin (being positive input-the 3 pin of U2) on voltage

VIN＝MIC_BIAS/(R1+RSPEAK)*RSPEAK＝3/(2.2K+32)*32＝0.04V

Wherein RSPEAK is exactly the typical resistance of the SPEAKER of earphone, 32 ohm.

Because VCC is through the dividing potential drop of R4 and R5, the voltage of anti-phase input-the 4th pin of comparer U2

VREF＝VCC/(R4+R5)*R5＝3/(250K+50K)*50K＝0.5V

Therefore the pin 1 of comparer U2 is output as low level, and microprocessor judges that according to this low level the earphone that inserts is the earphone of Class1.Therefore microprocessor is with the passage switch-over control signal HP_SELECT output low level of U1, and 2 pin that the control analog switch switches to J1 are the MIC input, and 4 pin are L channel SPEAKER output.

3, when inserting the earphone of type 2

This moment as insert Class1 the time, 3 pin of J1 become low level, have earphone to insert thereby microprocessor is judged, and MIC_BIAS is provided voltage.

This moment J1 4 pin and 1 pin between be MIC because the typical resistance of MIC is about 1.2K, the 3V voltage of this resistance and 1 couple of MIC_BIAS of resistance R carries out dividing potential drop, so the voltage on 4 pin (being 3 pin of U2) of J1 is at this moment

VIN＝MIC_BIAS/(R1+RMIC)*RMIC＝3/(2.2K+1.2K)*1.2K＝1.05V

Wherein RMIC is exactly the typical resistance of the MIC of earphone, 1.2K ohm.

Still for 0.5V, so the pin 1 of comparer U2 is output as high level by the voltage VREF of top 4 pin that calculate U2 this moment, and microprocessor judges that according to this high level the earphone that inserts is the earphone of type 2.Therefore microprocessor is with the passage switch-over control signal HP_SELECT output high level of U1, and 2 pin that the control analog switch switches to J1 are L channel SPEAKER output, and 4 pin are the MIC input.

Therefore, the present invention has realized the interface circuit of the earphone of can compatible two kinds of pinouts different 4pole types.The earphone insertion of being adopted in this example and the circuit design of type judging module and channel switching module all are general application modes, in actual use, can select other circuit form to satisfy specific requirement.Simultaneously according to the earphone in the concrete practical application, be used as other pins that input that earphone inserts and type is judged semaphore and passage switch may come from earphone socket.

The present invention only is the difference of its pinout according to the difference of the earphone with same mechanical structure, by judge inserting the type of earphone, the circuit of earphone interface is selected to switch, to reach the purpose that interface circuit can compatible a plurality of earphones.Adopt this way can effectively increase the versatility of the earphone interface circuit of portable type electronic product, help user flexibility when making things convenient for production and select used earphone, having solved in the past, product can only use a drawback that earphone special brought.

Being preferred embodiment of the present invention only in sum, is not to be used for limiting practical range of the present invention.Be that all equivalences of doing according to the content of the present patent application claim change and modification, all should be technology category of the present invention.

Claims

1, a kind of method that improves versatility of earphone interface, it is characterized in that: insert the earphone jack of equipment when earphone after, cause the pin electrical specification difference of different earphones because the pinout of different earphones is different, according to this characteristics equipment the type of earphone is differentiated, according to differentiating the result, selection commutation circuit in the microprocessor control earphone interface circuit in the equipment provides the distinct interface circuit at different earphones, thereby makes equipment can support multiple earphone.

2, the method for raising versatility of earphone interface according to claim 1 is characterized in that: described earphone pin electrical specification be not both that resistance value according to the sound channel of earphone and microphone is different to be distinguished.

3, the method for raising versatility of earphone interface according to claim 2 is characterized in that: not being both of described headset type realized by voltage comparator according to the electrical specification difference on the pin.

4, according to the method for any described raising versatility of earphone interface of claim 1 to 3, it is characterized in that: described selection commutation circuit realizes providing the distinct interface circuit at different earphones by analog switch.