CN201657320U

CN201657320U - Earphone plug-pull detecting circuit for mobile phone

Info

Publication number: CN201657320U
Application number: CN2010202273621U
Authority: CN
Inventors: 王富明; 罗恒; 石喜于
Original assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Current assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Priority date: 2010-06-12
Filing date: 2010-06-12
Publication date: 2010-11-24
Anticipated expiration: 2020-06-12

Abstract

The utility model discloses an earphone plug-pull detecting circuit for a mobile phone, comprising a Micro 5PIN interface connected on a mainboard of the mobile phone, wherein a four-pin series resistance of the Micro 5PIN I and a pull-up resistor R1 are connected with an inphase input terminal of a voltage comparator U1, an anti-phase input terminal of the voltage comparator U1 is connected between a pull-up resistor R4 and a pull-down resistor R5, an output terminal of the voltage comparator U1 is connected in series with a resistor R3 and then is connected to the input terminal of an interrupted signal detecting part to detect the plug-pull of an earphone, an earphone MIC is connected with the four-pin MIC signal input terminal of the Micro 5PIN. The earphone is detected by sensing the change of the level on the MIC network when the earphone is inserted or pulled out, thus the impact when the earphone is inserted or pulled out can be effectively eliminated, the function of the earphone MIC and the function of answering/hanging up the phone by the button on the earphone can not be influenced, the audio frequency effect of the mobile phone can be greatly improved.

Description

A kind of handset earphone plug testing circuit

Technical field

The utility model relates to a kind of testing circuit, particularly relates to a kind of detection of handset earphone that is used for for inserting or extract the status detection circuit.

Background technology:

When the Micro 5PIN multiplexing USB of existing mobile phone and earphone, the headset detection circuit is to realize by increase circuit on left and right sound channels, the shortcoming of this scheme is the coupling capacitance that must increase by two Da Rong values in circuit, and have greater impact sound when inserting earphone, bring certain negative effect can for user's audio frequency auditory effect.

The utility model content:

The purpose of this utility model is to overcome the deficiencies in the prior art, a kind of handset earphone plug testing circuit is provided, level when extracting by the insertion of perception earphone on the MIC circuit changes realizes headset detection, impulsive sound in the time of effectively solving the earphone plug, do not influence simultaneously the effect of microphone itself, and, can promote the audio experience effect of mobile phone products by a relatively large margin by earphone receiving, the function of hanging up the telephone.

In order to achieve the above object, the technical solution adopted in the utility model is: a kind of handset earphone plug testing circuit, comprise the Micro 5PIN interface that is connected on the cell phone mainboard, the 4 pin MIC pin series resistance R6 of Micro 5PIN are connected to the in-phase input end of voltage comparator U1, the in-phase input end of pull-up resistor R1 one termination voltage comparator U1, form the voltage signal acquisition circuit, another termination power of R1; The inverting input of voltage comparator U1 is connected between pull-up resistor R4 and the pull down resistor R5, another termination power of R4, and R5 other end ground connection, R4 and R5 dividing potential drop obtain reference voltage and are input to voltage comparator U1; The input that is connected to the interrupt signal test side behind the voltage comparator U1 output series resistance R3 detects earphone plug state; MIC bias supply forward series diode D1 and resistance R 2 are received the MIC circuit then, draw voltage to pour in down a chimney on preventing that R6 from introducing; Earphone is connected on the 4 pin MIC signal input parts of Micro 5PIN, when earphone inserts ear microphone over the ground equivalent resistance be Rmic.

If MIC is AVDD by the voltage of pull-up resistor R1, it is Vmic_bias that mobile phone baseband is given the bias voltage of MIC, the fashionable MIC voltage of the earless machine transplanting of rice is Vmic1, and MIC voltage was Vmic2 when earphone inserted, and the maximum of Vmic2 was Vmic2_max when earphone inserted and microphone is worked.MIC voltage is Vmic3 when earphone is in insertion state and talk key and is pinned.If voltage comparator U1 reference voltage is Vref.Circuit Vmic3＜Vmic2＜Vref＜the AVDD that satisfies condition; Vmic_bias＜AVDD.The MIC network is Vmic at the voltage of all states, and Vmic is one of them of Vmic1, Vmic2, Vmic3.

Vmic=Vmic1=AVDD＞Vref when not having earphone to insert, voltage comparator U1 exports high level, interrupts not responding; When earphone inserts and Vmic_bias when not opening, Vmic is AVDD through resistance R 1 and ear microphone equivalent resistance Rmic dividing potential drop over the ground, Vmic=Vmic2＜Vref, and voltage comparator U1 output low level, interrupt response detects earphone and inserts; When earphone insertion and Vmic_bias unlatching, Vmic is Vmic_bias through R2 and the ear microphone dividing potential drop of equivalent resistance Rmic over the ground, Vmic=Vmic2＜Vref, and voltage comparator U1 continues output low level, interrupt not responding, mobile phone thinks that earphone keeps the insertion state.When earphone keeps the insertion state, when pressing on the earphone receiving/hang-up key, earphone is equivalent resistance Rmic shorted to earth over the ground, Vmic=Vmic3＜Vref, function is answered and hung up to normal execution of mobile phone this moment, and voltage comparator U1 is failure to actuate, and continues output low level, interrupt not responding, mobile phone thinks that earphone is in the insertion state; When ear microphone is worked, obtain Vmic2_max according to earphone MIC gain and Vmic_bias, this moment Vmic2=Vmic2_max＜Vref, U1 continues to keep low level, interrupts not responding, mobile phone thinks that earphone is in the insertion state; When extracting earphone, earphone equivalent resistance Rmic over the ground disconnects from circuit, and MIC is drawn high by R1 by AVDD and is Vmic1, Vmic=Vmic1＞Vref, and voltage comparator U1 becomes high level from low level, and the mobile phone response is interrupted, and detects earphone and extracts.

Compared with prior art, the beneficial effects of the utility model are: the level of utilization voltage comparator U1 output changes the perception earphone and inserts when extracting the level of MIC network and change and realize headset detection, impulsive sound in the time of effectively solving the earphone plug, do not influence simultaneously the effect of MIC itself, and, can promote the audio experience effect of mobile phone products by a relatively large margin by earphone receiving, the function of hanging up the telephone.

Description of drawings:

Fig. 1 is circuit theory diagrams of the present utility model;

Fig. 2 is MIC signal interruption logical transition figure of the present utility model.

Embodiment:

Central idea of the present utility model is to overcome the deficiencies in the prior art, and a kind of handset earphone plug testing circuit is provided, and the impulsive sound in the time of effectively solving the earphone plug can promote the audio experience effect of mobile phone products by a relatively large margin.Be elaborated with reference to accompanying drawing below in conjunction with embodiment, so that technical characterictic of the present utility model and advantage are carried out more deep annotation.

Circuit theory diagrams of the present utility model as shown in Figure 1, a kind of handset earphone plug testing circuit comprises the Micro 5PIN interface that is connected on the cell phone mainboard, and Micro 5PIN is the female seat of multiplexing USB and mobile phone, its 4 pin connects the MIC signal and is input to mobile phone baseband, 5～9 pin ground connection.The 4 pin MIC pin series resistance R6 of Micro 5PIN are connected to the in-phase input end of voltage comparator U1, pull-up resistor R1 one termination AVDD, and the L other end is connected on the inverting input of voltage comparator U1; The inverting input of voltage comparator U1 is connected between pull-up resistor R4 and the pull down resistor R5, another termination of R4 AVDD, R5 other end ground connection; The input that is connected to the interrupt signal detection behind the voltage comparator U1 output series resistance R3 detects earphone plug state; MIC bias supply forward series diode D1 and resistance R 2 are received the MIC circuit then, draw voltage to pour in down a chimney on preventing that resistance R 6 from introducing; Earphone is connected on the 4 pin MIC signal input parts of Micro 5PIN, when earphone inserts over the ground equivalent resistance be Rmic.

It is 2.8V that AVDD is set, and Vmic_bias is that 2.2V. selects resistance R 1=100K, R2=2.5K, and R3=R6=1K, R4=24K, R5=51K, R7=10R, Rmic is about 2K.Can get Vref=1.9V according to circuit theory diagrams, ignore diode drop, Vmic1=2.2V then, Vmic2=0.98V, Vmic3=0V.Vmic2 crest voltage Vmic2_max=1.7V＜Vref during actual measurement MIC work.The Vref surplus rationally and satisfy the condition of Vmic3＜Vmic2＜Vref＜AVDD.

MIC signal interruption logical transition figure earphone plug, answers and hangs up and converse, during earphone MIC work such as recording, can exert an influence to the MIC network voltage as shown in Figure 2.Choose suitable reference voltage Vref, with the output state after MIC current state voltage Vmic and the reference voltage Vref comparison, judge whether current earphone is in insertion or extracts state through over-voltage comparator U1.

Vmic=2.8V＞Vref when not having earphone to insert, voltage comparator U1 exports high level, interrupts not responding; When earphone inserts and Vmic_bias when not opening, Vmic is AVDD through resistance R 1 and ear microphone equivalent resistance Rmic dividing potential drop over the ground, Vmic=Vmic2=0.05V＜Vref, and voltage comparator U1 output low level, interrupt response, mobile phone detects earphone and inserts; When earphone insertion and Vmic_bias unlatching, Vmic is Vmic_bias through R2 and the ear microphone dividing potential drop of equivalent resistance Rmic over the ground, Vmic=Vmic2=0.98V＜Vref, and voltage comparator U1 keeps low level, interrupt not responding, mobile phone thinks that earphone keeps the insertion state; When earphone keeps the insertion state, when pressing on the earphone receiving/hang-up key, earphone is equivalent resistance Rmic shorted to earth over the ground, Vmic=Vmic3=0V＜Vref, function is answered and hung up to normal execution of mobile phone this moment, and voltage comparator U1 is failure to actuate, and continues output low level, interrupt not responding, mobile phone thinks that earphone is in the insertion state; When earphone is in insertion state and earphone MIC work, Vmic2_max=1.7V＜Vref, voltage comparator U1 is failure to actuate, and continues output low level, interrupts not responding, and mobile phone thinks that earphone is in the insertion state; When extracting earphone, earphone equivalent resistance Rmic over the ground disconnects from circuit, and MIC is drawn high by R1 by AVDD and is Vmic1, Vmic=Vmic1=2.8V＞Vref, and voltage comparator U1 becomes high level from low level, and the mobile phone response is interrupted, and detects earphone and extracts.

In the above-described embodiments, the value of magnitude of voltage and resistance, inductance all is a preset value, unfixing, although the utility model has been made clear and complete description by specific embodiment to it, but the utility model is not limited only to described embodiment, and to one skilled in the art, all improvement and the selection made based on the utility model are contingent and all be included among the utility model.

Claims

1. a handset earphone plug testing circuit comprises the Micro 5PIN interface that is connected on the cell phone mainboard, it is characterized in that:

The 4 pin series resistance R6 of Micro 5PIN are connected to the in-phase input end of voltage comparator U1, and pull-up resistor R1 one terminates at the in-phase input end of voltage comparator U1, another termination power of R1;

The inverting input of voltage comparator U1 is connected between pull-up resistor R4 and the pull down resistor R5, another termination power of R4, R5 other end ground connection;

Diode D1 positive pole connects the MIC bias supply, negative pole connecting resistance R2, resistance R 2 another termination MIC circuits;

Be connected to interrupt signal behind the voltage comparator U1 output series resistance R3 and detect input.

2. handset earphone according to claim 1 plug testing circuit, it is characterized in that: ear microphone is connected on the 4 pin MIC signal input parts of Micro 5PIN, when earphone inserts MIC over the ground equivalent resistance be Rmic.