TW201901164A - Headphone impedance detection system - Google Patents

Abstract

This disclosure is related to a headphone impedance detection system. The headphone impedance detection system includes an analog audio witch controller, a headphone impedance detector, a MCU, a DAC unit, a right current/voltage converter (R), a left current/voltage converter (L) and a high fidelity headphone amplifier. The input of the high fidelity headphone amplifier is coupled to the right current/voltage converter (R) and the left current/voltage converter (L). The output of the high fidelity headphone amplifier is coupled to the analog audio switch controller so that the output of the high fidelity headphone amplifier can be transmitted to the headphone input terminal to transmit the high fidelity audio signals to the headphones. Further when the headphone impedance detector reads the impedance value of the headphones, the impedance value is transmitted to the MCU. The MCU controls the analog volume signals output from the DAC unit according to a DAC table, and then transmitted the analog volume signals to the right current/voltage converter (R) and the left current/voltage converter (L).

Description

 Headphone impedance detection system  

The invention discloses a smart earphone impedance detecting system, in particular to a headphone impedance detecting system for automatically detecting the impedance value of the earphone when the earphone is inserted into the earphone input terminal, and outputting the high-fax music.

Existing computer systems, especially in notebook-related devices, are not provided with the ability to automatically detect the impedance of the headphones. Generally speaking, under the design of the existing computer system, when it is required to be able to support both the 600 Ω and the general 32 Ω earphones, the amplified power value of the earphone is designed to be generally suitable for a 32 Ω earphone. In this case, the sound of a general 32 Ω headphone sounds just right, but when you want to push a 600 Ω headphone, the sound it plays will be too low. On the other hand, if the amplification power of the earphone is designed to be larger, it can be applied to a 600Ω earphone, and the sound of the 600Ω earphone is sounded moderately. However, when the 32Ω earphone is played, the amplification power is too large. And the sound is too loud, not only hurting the ear or even burning the headphones. Need to be improved.

The invention discloses a smart earphone impedance detecting system. The earphone impedance detecting system of the invention is arranged in a computer system, so that various computer systems can automatically detect the impedance of the earphone, and according to different impedances of the earphone To control the amplification power of the headphones. Regardless of the various forms of headphones that the user inserts into any impedance value, the computer system will output a sound that is acceptable for the human ear, and the volume that the human ear can comfortably listen to, so that the volume is too large or too small, and most importantly, it will not hurt. The ear will not burn the headphones, greatly improving the lack of existing technology.

The earphone impedance detecting system of the present invention comprises: a headphone input terminal; an analog audio switch controller coupled to the earphone input terminal; and an earphone impedance detector coupled to the analog audio switch controller a programmable control unit coupled to the headphone impedance detector; a digital analog control unit coupled to the programmable control unit; a right channel current to voltage converter coupled to the digital analog control unit a left channel current to voltage converter coupled to the digital analog control unit; and a high fax headphone amplifier coupled to the right channel current to voltage converter and the left channel current to voltage converter; And the output of the high-fashion headphone amplifier is coupled to the analog audio switch controller, so that the output of the high-fashion headphone amplifier can be transmitted to the earphone input terminal.

When the earphone input terminal is inserted into the earphone, the analog audio switch controller connects the earphone switch to the earphone impedance detector, and then the analog audio switch controller connects the earphone switch to the high-fashion headphone amplifier; wherein After the earphone impedance detector reads the impedance value of the earphone, transmitting the impedance value of the earphone to the programmable control unit, and the programmable control unit performs control of the digital analog control unit according to a digital analog conversion volume meter. The digits are converted to analog control.

Further, the digital analog control unit converts the digit conversion into analog control, that is, controls the digital analog control unit to different impedance values of the earphone, corresponding to different volume outputs, and the volume output passes the right The channel current to voltage converter and the left channel current to voltage converter can convert the current into a voltage and output it as an audio signal. After that, the audio signal is amplified by the high-frequency headphone amplifier, and the audio signal is transmitted to the earphone input terminal through the analog audio switch controller, and then transmitted to the earphone, so that the user can hear the high-acceptance suitable for the human ear and acceptable to the human body. music.

10‧‧‧ headphone input terminal

20‧‧‧ analog audio switch controller

21‧‧‧First right signal

22‧‧‧first left signal

23‧‧‧second right signal

24‧‧‧second left signal

25‧‧‧Switching elements

26‧‧‧Circuit components

27‧‧‧II

28‧‧‧Double switch

30‧‧‧Headphone Impedance Detector

40‧‧‧Programmable Control Unit

50‧‧‧Digital Analog Control Unit

51‧‧‧Digital Analog Control Unit Right Output Signal

51a‧‧‧ first end

51b‧‧‧ second end

52‧‧‧Digital analog control unit left output signal

52a‧‧‧a

52b‧‧‧bth

60‧‧‧Right channel current to voltage converter

61‧‧‧Right channel current to voltage converter output signal

62‧‧‧First amplifier

63‧‧‧Second amplifier

64‧‧‧First feedback impedance

65‧‧‧Second feedback impedance

70‧‧‧Left channel current to voltage converter

71‧‧‧Left channel current to voltage converter output signal

72‧‧‧3rd amplifier

73‧‧‧4th amplifier

74‧‧‧ Third feedback impedance

75‧‧‧ fourth feedback impedance

80‧‧‧High-Fax Headphone Amplifier

81‧‧‧High-Fax Headphone Amplifier Right Output Signal

82‧‧‧High-Fax Headphone Amplifier Left Output Signal

83‧‧‧First High Fax Amplifier

84‧‧‧Second high fax amplifier

90‧‧‧Audio decoder

VCC‧‧‧ power supply

VREF‧‧‧reference voltage

CON‧‧‧ switch control signal

R61‧‧‧First resistance

R62‧‧‧second resistance

R71‧‧‧ third resistor

R72‧‧‧ fourth resistor

C61‧‧‧first capacitor

C71‧‧‧second capacitor

R81~R84‧‧‧First to fourth feedback resistors

C81~C84‧‧‧first to fourth feedback capacitor

R85, R86‧‧‧ series resistor

1 is a schematic structural diagram of a circuit block according to an embodiment of the present invention; FIG. 2 is a schematic circuit diagram of an analog audio switch controller according to an embodiment of the present invention; and FIG. 3 is a circuit diagram of a right channel current-to-voltage converter according to an embodiment of the present invention; 4 is a circuit diagram of a left channel current to voltage converter according to an embodiment of the present invention; and FIG. 5 is a circuit diagram of a high fax headphone amplifier according to an embodiment of the present invention.

The exemplary embodiments are described more fully hereinafter with reference to the accompanying drawings However, the inventive concept may be embodied in many different forms and should not be construed as limited to the illustrative embodiments set forth herein. Rather, these exemplary embodiments are provided so that this invention will be in the In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity. Similar numbers always indicate similar components.

It should be understood that although the terms right (R), left (L), right signal, or left signal, etc., may be used herein to describe various elements and their corresponding signals or output signals, such elements are not limited by such terms. . These terms are used to clearly distinguish one element from another. Therefore, the right (R) component, the right signal or the right output signal discussed below may also be referred to as a left (L) component, a left signal or a left output signal, etc. without departing from the teachings of the inventive concept. The terms first, second, third or fourth, etc., as used herein, are used to clearly distinguish one element from another element, and are not intended to limit the order in which the character number is presented. Relationship, meaning between the first and the second, has no corresponding order relationship. Also, the term "and/or" may be used to include any of the associated listed items and all combinations of one or more. Furthermore, the plural terms may be used herein to describe a plurality of elements, but the plural elements are not limited to the implementation of techniques in which two, three or four and four or more elements are represented.

The invention relates to a smart earphone impedance detecting system. With the setting of the earphone impedance detecting system of the invention, various computer systems can automatically detect the impedance of the earphone, and control the amplification of the earphone according to different impedances of the earphone. power. Regardless of whether the user inserts a headphone with any impedance value, the computer system will output a sound suitable for the human ear, and the volume that the human ear can comfortably listen to, does not cause the volume to be too large or too small, and most importantly, does not hurt the ear or even Will burn the headphones.

As shown in FIG. 1 , the earphone impedance detecting system of the present invention includes a headphone input terminal 10, an analog audio switch controller 20, a headphone impedance detector 30, a programmable control unit 40, and a digital device. Analog control unit 50, a right channel current to voltage converter 60, a left channel current to voltage converter 70, a high fax headphone amplifier 80, and an audio decoder 90. The analog audio switch controller 20 is coupled to the earphone input terminal 10; the earphone impedance detector 30 is coupled to the analog audio switch controller 20; the programmable control unit 40 is coupled to the earphone impedance detector 30; The analogy control unit 50 is coupled to the programmable control unit 40; the right channel current to voltage converter 60 is coupled to the digital analog control unit 50; the left channel current to voltage converter 70 is coupled to the digital analog control unit 50; The high-facsimile headphone amplifier 80 is coupled to the right channel current to voltage converter 60 and the left channel current to voltage converter 70; and the output of the high-fax headphone amplifier 80 is coupled to the analog audio switch controller 20 to enable the high-facance headphone amplifier The output of 80 can be transmitted to the headphone input terminal 10. The audio decoder 90 is coupled to the digital analog control unit 50; the digital analog control unit 50 outputs a digital analog control unit right output signal 51 and a digital analog control unit left output signal 52.

When the user inserts the earphone into the earphone input terminal 10 by the coupling relationship of the circuit components, the analog audio switch controller 20 switches the earphone switch to the earphone impedance detector 30, and then the analog audio switch controller 20 The headphone switch is connected to the high-fax headphone amplifier 80. In addition, when the earphone impedance detector 30 reads the impedance value of the earphone and transmits the impedance value of the earphone to the programmable control unit 40, the programmable control unit 40 converts the volume meter according to a digital analogy (such as Table 1). The control for controlling the digital conversion of the digital analog control unit 50 to analogy is performed.

The above-mentioned digital analog control unit 50 digitally converts the analog to the analog control, which means that the digital analog control unit 50 controls the impedance values of the different headphones to detect different volume outputs. Thereafter, the volume output is passed through the right channel current to voltage converter 60 and the left channel current to voltage converter 70, and the current is converted into a voltage and output as an audio signal. Further, the audio signal is amplified by the high-facsimile headphone amplifier 80 to output a high-fax audio signal, and the high-fidelity audio signal is transmitted to the earphone via the analog audio switch controller 20 to make the earphone. Get high-fidelity music. And the sound effect decoder 90 is a music player that is used by a computer system (which can be used for different computer systems, such as a notebook computer, a desktop computer, a smart phone or a tablet computer). The music decodes the high-fidelity digital signal via the sound effect decoder 90 and transmits it to the digital analog control unit 50.

The description of the above technical contents will be further described in conjunction with the functions of the respective circuit block elements of FIG. First, when the user inserts the earphone through the earphone input terminal 10, the analog audio switch controller 20 switches the earphone to the earphone impedance detector 30, and the earphone impedance detector 30 performs two actions after reading the earphone impedance: Action 1: The impedance value of the earphone is transmitted to the programmable control unit 40, and the programmable control unit 40 further controls according to the comparison table of the headphone impedance and the digital analog conversion (DAC) volume in the volume analog meter (Table 1). The volume is converted to the volume output of the control unit 50; action 2: The analog audio switch controller 20 switches the headphones to the high-facance headphone amplifier 80. The computer system uses the music player to decode the high-fidelity music through the sound decoder 90 to decode the high-fidelity digital signal, and the high-fidelity digital signal is output to the left-channel analog analog small unit by the digital analog control unit 50, that is, the volume. The output is then converted to a voltage audio signal via the right channel current to voltage converter 60 and the left channel current to voltage converter 70, and the audio signal is amplified by the high fax headphone amplifier 80, and the audio signal is analogized. The switch controller 20 transmits to the earphone input terminal 10 and transmits it to the earphone, so that the user can hear high-fax music that is acceptable to the human ear and is immersive.

For the aforementioned digital analog conversion volume meter, as shown in the following list 1.

Table I:

In the invention, the earphone impedance detector 30 is used to read the impedance value of the earphone, and the impedance value of the earphone is transmitted to the programmable control unit 40. The programmable control unit 40 converts the headphone impedance and the digital analog conversion (DAC) according to Table 1. The corresponding comparison table of the volume output further controls the volume output of the digital to analog control unit 50. The invention is based on a 600 Ω earphone for maximum volume output, and the volume analog output of the digital analog conversion (DAC) is controlled to be -0 dB, indicating that the maximum output volume of the digital analog conversion (DAC) is not attenuated; however, when the headphone impedance value is higher Small, the greater the maximum volume output attenuation of the digital analog conversion (DAC), such as the earphones below 48Ω for the minimum volume output, the digital analog conversion (DAC) volume output control is -20dB, indicating digital analog conversion ( The maximum output volume of the DAC) is attenuated by -20dB, so it is necessary to amplify the volume output signal.

Another function of the present invention is high-fashion headphone sound output, which can listen to high sampling rate (Sample Rate: 192KHz) and high resolution (Resolution: 24bit) music format output through the earphone, and high resolution (Hi-Resolution) to the trend The ultimate performance of the original music reproduces the quality of the music, allowing the user to truly feel the presence of the original singer or performer in the live performance.

2 is a diagram illustrating in further detail the composition and mutual coupling of the internal circuit components of the analog audio switch controller 20. The analog audio switch controller 2 includes a double switch 28, a coil component 26, a diode 27 and a switching component 25. One end of the double-turn switch 28 (the left end shown in FIG. 2) is a first right signal 21 and a first left signal 22; and the other end of the double-turn switch 28 (the right side shown in FIG. 2) The end is coupled to the input of the headphone impedance detector 30. As shown in FIG. 2, a second right signal 23 and a second left signal 24 are coupled. The other end of the double-turn switch 28 is coupled to the output end of the high-fake headphone amplifier 80. As shown in FIG. 2, a high-fax headphone amplifier right output signal 81 and a high-facance headphone amplifier left output signal 82 are coupled. . The double-turn switch 28 is also provided with a control end as shown by the dashed end of the double-turn switch 28 in FIG. The coil element 26 is coupled to the control end of the double-turn switch 28. The cathode end of the diode 27 is coupled to a power source VCC, and the anode end of the diode 27 is coupled to the 汲 terminal of the switching element 25. The 汲 terminal of the switching element 25 is coupled to the coil element 26, the source terminal of the switching element 25 is grounded, and the gate terminal of the switching element 25 is coupled to a switching control signal CON. Thus, the analog audio switch controller 2 can perform switching connection of the earphone inserted by the user to the earphone impedance detector 30 and can be switched to be connected to the high-facance headphone amplifier 80.

In addition, in FIG. 1, an embodiment in which the earphone impedance detector 30 is used in an actual circuit is an impedance detector capable of using a voltage dividing circuit, with different and/or the same impedance values. The plurality of resistors are connected in series to form an impedance detector to detect the voltage value corresponding to the impedance of the earphone, and the impedance detection of the earphone impedance detector 30 is achieved.

FIG. 3 is a diagram showing the relationship between the composition and the mutual coupling of the internal circuit components of the right channel current to voltage converter 60 in further detail. The right channel current to voltage converter 60 includes a first amplifier 62 and a second amplifier 63. The inverting input end of the first amplifier 62 is coupled to a first end 51a of the right analog signal 51 of the digital analog control unit output by the digital analog control unit 50. A first feedback impedance 64 is coupled between the non-inverting input of the first amplifier 62 and the output. The first feedback impedance 64 can be connected in series with a resistor, and then connected in parallel with a resistor to complete the first feedback impedance 64 circuit, as shown in FIG.

In addition, the inverting input end of the second amplifier 63 is coupled to a second end 51b of the digital analog control unit right output signal 51 output by the digital analog control unit 50; the non-inverting input and output of the second amplifier A second feedback impedance 65 is connected between the two, and the second feedback impedance 65 circuit component has the same composition as the first feedback impedance 64. And, the first amplifier 62 is connected to the non-inverting input terminal of the second amplifier 63, and is connected to a reference voltage VREF. The reference voltage VREF is composed of a power supply VCC through a series connection voltage of a first resistor R61 and a second resistor R62. The second resistor R62 is connected in parallel with a first capacitor C61. The output of the first amplifier 62 and the second amplifier 63 is a right channel current to voltage converter output signal 61.

4 is a diagram illustrating in further detail the composition and mutual coupling of the internal circuit components of the left channel current to voltage converter 70. The left channel current to voltage converter 70 includes a third amplifier 72 and a fourth amplifier 73. The inverting input end of the third amplifier 72 is coupled to an a-th end 52a of the digital analog control unit left output signal 52 output by the digital analog control unit 50. A third feedback impedance 74 is coupled between the non-inverting input and the output of the third amplifier 72. The third feedback impedance 74 can be connected in series with a resistor, and then connected in parallel with a resistor to complete the third feedback impedance 74 circuit, as shown in FIG.

At the same time, the inverting input terminal of the fourth amplifier 73 is coupled to a b-th terminal 52b of the digital analog control unit left output signal 52 output by the digital analog control unit 50; the non-inverting input terminal and the output terminal of the fourth amplifier There is a fourth feedback impedance 75 connected between them, and the fourth feedback impedance 75 circuit component has the same composition as the third feedback impedance 74. On the other hand, the third amplifier 72 is connected to the non-inverting input terminal of the fourth amplifier 73, and is connected to a reference voltage VREF. The reference voltage VREF is composed of a power supply VCC through a series connection voltage of a third resistor R71 and a fourth resistor R72. The fourth resistor R72 is connected in parallel with a second capacitor C71. The output of the third amplifier 72 and the fourth amplifier 73 is a left channel current to voltage converter output signal 71.

As shown in FIG. 5, to further disclose an internal component circuit of the high-fc headset amplifier 80, the high-fax headphone amplifier 80 includes a first high-fax amplifier 83 and a second high-fax amplifier 84. A first feedback resistor R81 is coupled between the non-inverting input end and the output end of the first high-fax amplifier 83, and the other end of the first feedback resistor R81 is grounded, and the first feedback resistor R81 is A first feedback capacitor C81 is connected in parallel. A third feedback resistor R83 is coupled between the inverting input terminal and the output terminal of the first high-fax amplifier 83. The third feedback resistor R83 has a third feedback capacitor C83 connected in parallel.

A fourth feedback resistor R84 is coupled between the non-inverting input end and the output end of the second high-fax amplifier 84, and the other end of the fourth feedback resistor R84 is grounded, and the fourth feedback resistor R84 is connected in parallel with the first Four feedback capacitor C84. A second feedback resistor R82 is coupled between the inverting input terminal and the output terminal of the second high-fax amplifier 84. The second feedback resistor R82 is coupled with a second feedback capacitor C82.

In FIG. 5, the non-inverting input terminal and the inverting input terminal of the first high-fax amplifier 83 are individually coupled to the right-channel current-to-voltage converter output signal 61 output by the right channel current-to-voltage converter 60. The two output terminals of the right channel current to voltage converter output signal 61 are individually connected with a series resistor R85 as the amplification gain of the first high fax amplifier 83; and the non-inverting input of the second high fax amplifier 84 The left and right input terminals are respectively coupled to the left channel current to voltage converter output signal 71 output by the left channel current to voltage converter 70, and the two outputs of the left channel current to voltage converter output signal 71 are respectively output. The terminal is individually connected with a series resistor R86 as an amplification gain calculation of the second high-fax amplifier 84. The output of the first high-fax amplifier 83 is the high-output headphone amplifier right output signal 81, and the output of the second high-fax amplifier 84 is the high-fax headphone amplifier left output signal 82, that is, the output of the high-facsimile headphone amplifier 80. The left side of the high-fax headphone amplifier output signal 81 and the high-fed headphone amplifier left output signal 82. Thereby, the circuit composition of the high-facing headphone amplifier 80 is completed.

In summary, the present invention provides a headphone impedance detecting system that can be installed in various types of computer devices, such as a notebook computer, a desktop computer, a smart phone, or a tablet computer. With the setting of the earphone impedance detecting system of the present invention, various computer systems can automatically detect the impedance of the earphone, and control the amplification power of the earphone according to different impedances of the earphone. Regardless of whether the user inserts a headphone with any impedance value, the computer system will output a sound suitable for the human ear, and the volume that the human ear can comfortably listen to, does not cause the volume to be too large or too small, and most importantly, does not hurt the ear or even It will burn the headphones and effectively improve the lack of existing technology. It is obvious that the present invention has the requirements for patent application. However, the description of the present invention is merely illustrative of the preferred embodiments, and the scope of the present invention is not limited thereto, and any local variation, modification, or addition is not deviated from the scope of the present invention. in.

Claims (10)

 An earphone impedance detecting system includes: a headphone input terminal; an analog audio switch controller coupled to the earphone input terminal; a headphone impedance detector coupled to the analog audio switch controller; a control unit coupled to the headphone impedance detector; a digital analog control unit coupled to the programmable control unit; a right channel current to voltage converter coupled to the digital analog control unit; a current-to-voltage converter coupled to the digital analog control unit; and a high-facsimile headphone amplifier coupled to the right-channel current-to-voltage converter and the left-channel current-to-voltage converter; and the high-fax The output of the headphone amplifier is coupled to the analog audio switch controller, so that the output of the high-fashion headphone amplifier can be transmitted to the earphone input terminal; wherein, when the earphone input terminal is inserted into the earphone, the analog audio switch controller will The earphone switch is connected to the earphone impedance detector, and then the analog switch controller connects the earphone switch to the high-facance headphone amplifier; After the earphone impedance detector reads the impedance value of the earphone, the impedance value of the earphone is transmitted to the programmable control unit, and the programmable control unit performs control of the digital analog control according to a digital analog conversion volume meter. The unit's digit conversion is analogous to the control.    The earphone impedance detecting system according to Item 1, wherein the digital analog control unit converts the digits into analog control, and controls the digital analog control unit to correspond to different impedance values of the earphone, corresponding to Different volume outputs are output, and the volume output passes through the right channel current to voltage converter and the left channel current to voltage converter, and the current is converted into a voltage and output as an audio signal.    The earphone impedance detecting system of claim 2, wherein the audio signal is amplified by the high-fashion headphone amplifier to output a high-facsimile audio signal, and the high-fidelity audio signal is further transmitted through the analog audio signal. A switch controller is transmitted to the headset to enable the headset to obtain high-fidelity music.    The headphone impedance detecting system of claim 1, wherein the digital analog control unit is further coupled with an audio decoder capable of decoding the music to be played through the audio decoder to decode the high-fidelity digit. The signal is then transmitted to the digital analog control unit.    The earphone impedance detecting system of claim 1, 2, 3 or 4, wherein the analog audio switch controller comprises: a double switch, one end of the double switch is a first right signal and a first left signal; the other end of the double-turn switch includes an input end of the earphone impedance detector and an output end of the high-facance headphone amplifier; the double-turn switch is provided with a control end; a coil component, coupled Connected to the control end of the double-turn switch; a diode, the cathode end of the diode is coupled to a power supply; and a switching element, the first end of the switching element is coupled to the coil element and coupled to the second An anode terminal of the pole body, a source terminal of the switching element is grounded, and a gate terminal of the switching component is coupled to a switch control signal.    The earphone impedance detecting system of claim 1, 2, 3 or 4, wherein the earphone impedance detector is an impedance detector of a voltage dividing circuit.    The earphone impedance detecting system of claim 1, 2, 3 or 4, wherein the right channel current to voltage converter comprises: a first amplifier, an inverting input of the first amplifier a first end of the right output signal of the digital analog control unit outputted by the digital analog control unit; a first feedback impedance connected between the non-inverting input end and the output end of the first amplifier; a second amplifier, the inverting input end of the second amplifier is coupled to a second end of the right analog output signal of the digital analog control unit output by the digital analog control unit; the non-inverting input end of the second amplifier A second feedback impedance is coupled between the outputs; wherein the first amplifier is coupled to the non-inverting input of the second amplifier and is coupled to a reference voltage.    The earphone impedance detecting system of claim 1, 2, 3 or 4, wherein the left channel current to voltage converter comprises: a third amplifier, an inverting input of the third amplifier The first analog terminal is coupled to the first output of the left output signal of the digital analog control unit; the third analog feedback impedance is coupled between the non-inverting input terminal and the output terminal of the first amplifier; a fourth amplifier, the inverting input end of the fourth amplifier is coupled to a b-th end of the left analog signal of the digital analog control unit output by the digital analog control unit; the non-inverting input and output of the second amplifier A fourth feedback impedance is coupled between the terminals; wherein the third amplifier is coupled to the non-inverting input of the fourth amplifier and is coupled to a reference voltage.    The earphone impedance detecting system of claim 1, 2, 3 or 4, wherein the high-facsimile headphone amplifier comprises: a first high-fax amplifier, a non-inverting input of the first high-fax amplifier A first feedback resistor is coupled to the output end, and the other end of the first feedback resistor is grounded; a third feedback resistor is coupled between the inverting input end and the output end of the first high-fax amplifier And a second high-fax amplifier, a non-inverting input end and an output end of the second high-fax amplifier are coupled to a fourth feedback resistor, and the other end of the fourth feedback resistor is grounded; the second A second feedback resistor is coupled between the inverting input end and the output end of the high-fax amplifier; wherein the non-inverting input end and the inverting input end of the first high-fax amplifier are individually coupled to the right channel current a right channel current to voltage converter output signal outputted by the voltage converter, the right channel current to voltage converter output signal is individually connected with a series resistor; and the second high fax amplifier has a non-inverting input terminal Reverse input Left channel coupled to the current left channel current-to-voltage converter output signal-to-voltage converter output, left channel of the current-to-voltage converter output signal is connected to a respective series resistor.    The earphone impedance detecting system of claim 9, wherein the first feedback resistor of the first high-fax amplifier has a first feedback capacitor connected in parallel, and the third feedback resistor has a third feedback in parallel. The fourth feedback resistor of the second high-fax amplifier has a fourth feedback capacitor connected in parallel, and the second feedback resistor has a second feedback capacitor connected in parallel.