A communication circuit and motherboard testing device

Abstract

The application discloses a communication circuit and relates to the technical field of electrical appliances.The application comprises a communication interface, a preprocessing module, an analog-digital converter, an optoelectronic coupling module, a control module and a pull-up resistor.The communication interface is coupled with a test mainboard, and the preprocessing module is coupled with the communication interface to adjust input analog voltage.The analog-digital converter is coupled with the preprocessing module to perform analog-digital conversion on the voltage.The optoelectronic coupling module is coupled with the analog-digital converter.The control module is coupled with the optoelectronic coupling module to form optoelectronic separation between the analog-digital converter and the optoelectronic coupling module.The pull-up resistor is coupled between the output end of the control module and the output end of the optoelectronic coupling module, so that when the control module supplies power to the pull-up resistor, the output end of the optoelectronic coupling module outputs a digital signal that is proportional to the signal output by the analog-digital converter.Thus, the interference signals of the test mainboard and the control module can be optoelectronically isolated, and the influence of the interference signals on the test mainboard is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrical appliances, in particular to a communication circuit and a mainboard testing device. BACKGROUND

[0002] At present, various electrical appliances usually include a mainboard, and in the process of assembling the electrical appliances, a mainboard testing device is usually used to test the mainboard of the electrical appliances, which can load appropriate excitation and load to make the mainboard work in various states, and then obtain the parameters of the mainboard in various states to evaluate whether the output response of the mainboard meets the requirements.

[0003] However, when the mainboard testing device is connected with the mainboard, the communication in the mainboard testing device may have other interference signals affecting the operation of the mainboard, thereby reducing the testing accuracy of the mainboard. SUMMARY

[0004] In view of the above problems, the present application is proposed in order to provide a communication circuit and a mainboard testing device which can overcome the above problems or at least partially solve the above problems.

[0005] Based on the first aspect of the present application, the present application provides a communication circuit, which comprises:

[0006] a communication interface, which is used to be coupled with a test mainboard;

[0007] a preprocessing module, which is coupled with the communication interface to adjust an analog voltage output by the test mainboard;

[0008] an analog-to-digital converter, which is coupled with the preprocessing module to perform analog-to-digital conversion on the voltage output by the preprocessing module;

[0009] an optoelectronic coupling module, which is coupled with the analog-to-digital converter;

[0010] a control module, which is coupled with the optoelectronic coupling module to form an optoelectronic separation between the analog-to-digital converter and the optoelectronic coupling module, and to control the output of the digital signal of the analog-to-digital converter through the control module.

[0011] Optionally, the optoelectronic coupling module comprises a transmitter and a receiver, wherein the receiver is coupled with the control module, and the transmitter is coupled with the analog-to-digital converter.

[0012] Optionally, the circuit further comprises a first filtering module, which is coupled between the preprocessing module and the analog-to-digital converter to filter the voltage output by the preprocessing module.

[0013] Optionally, the first filter module comprises:

[0014] a bridge rectifier unit, which is coupled between the pre-processing module and an analog-to-digital converter;

[0015] an electrolytic capacitor, which is coupled between the bridge rectifier unit and the analog-to-digital converter.

[0016] Optionally, the bridge rectifier unit comprises:

[0017] a first diode;

[0018] a second diode, a positive electrode of which is coupled to a negative electrode of the first diode, and a coupling position of which is coupled to a positive output terminal of the pre-processing module;

[0019] a third diode, a negative electrode of which is coupled to a negative electrode of the second diode, and a coupling position of which is coupled to a positive input terminal of the analog-to-digital converter;

[0020] a fourth diode, a negative electrode of which is coupled to a positive electrode of the third diode, and a coupling position of which is coupled to a negative output terminal of the pre-processing module; wherein,

[0021] a positive electrode of the first diode is coupled to a positive electrode of the fourth diode, and a coupling position of which is coupled to a negative input terminal of the analog-to-digital converter, and the electrolytic capacitor is connected in parallel to an input terminal of the analog-to-digital converter, and a positive electrode of the electrolytic capacitor is coupled to a negative electrode of the third diode.

[0022] Optionally, the circuit further comprises an operational amplifier module, an input terminal of which is coupled to the pre-processing module, and an output terminal of which is coupled to the first filter module.

[0023] Optionally, the operational amplifier module comprises:

[0024] an operational amplifier, a positive phase input terminal of which is coupled to a positive output terminal of the pre-processing module, wherein an output terminal of the operational amplifier is coupled to the first filter module;

[0025] a first resistor, one end of which is coupled to a negative phase input terminal of the operational amplifier, and the other end of which is grounded;

[0026] a second resistor, which is coupled between the negative phase input terminal of the operational amplifier and the output terminal of the operational amplifier;

[0027] a third resistor, one end of which is coupled to the output terminal of the operational amplifier, and the other end of which is grounded.

[0028] Optionally, the pre-processing module comprises:

[0029] a second filtering unit coupled with the communication interface to filter the analog voltage output by the test mainboard;

[0030] a gain unit coupled with the second filtering unit to perform gain adjustment on the analog voltage output by the second filtering unit, wherein the gain unit is coupled with the analog-digital converter.

[0031] Optionally, the pre-processing module further comprises an overvoltage protection unit coupled between the gain unit and the analog-digital converter.

[0032] Optionally, the pre-processing module further comprises an overcurrent protection unit coupled between the gain unit and the analog-digital converter.

[0033] Optionally, the pre-processing module further comprises an electrostatic protection unit coupled between the gain unit and the analog-digital converter.

[0034] Optionally, the communication interface is one of a USB interface, an RS232 interface and an RS485 interface.

[0035] Based on the second aspect of the present application, the present application further provides a mainboard testing device, which comprises the communication circuit as described in any one of the above-mentioned aspects.

[0036] Compared with the prior art, the present application comprises a communication interface, a pre-processing module, an analog-digital converter, an optoelectronic coupling module, a control module and a pull-up resistor. The communication interface is used to couple with a test mainboard, the pre-processing module is coupled with the communication interface to adjust the analog voltage output by the test mainboard. The analog-digital converter is coupled with the pre-processing module to perform analog-digital conversion on the voltage output by the pre-processing module. The optoelectronic coupling module is coupled with the analog-digital converter. The control module is coupled with the optoelectronic coupling module to form optoelectronic separation between the analog-digital converter and the optoelectronic coupling module. The input end of the analog-digital converter is coupled with the output end of the optoelectronic coupling module, and the control module is coupled with the output end of the optoelectronic coupling module. The pull-up resistor is coupled between the control module and the output end of the optoelectronic coupling module, so that when the control module supplies power to the pull-up resistor, the output end of the optoelectronic coupling module outputs a digital signal proportional to the signal output by the analog-digital converter. In this way, the corresponding related interference signals of the test mainboard and the control module in the communication circuit can be optoelectronically isolated, the influence of the interference signals in the test site on the test of the test mainboard is reduced, and the test accuracy of the test mainboard is improved.

[0037] The above description is only a summary of the technical scheme of the present application. In order to make the technical means of the present application more clearly understood and implemented according to the content of the specification, and in order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the following specific embodiments of the present application are described. BRIEF DESCRIPTION OF DRAWINGS

[0038] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are intended to depict only preferred embodiments of the application, and therefore should not be considered to narrow the scope of the present application in any way. Instead, they are included to provide illustration of the preferred embodiments of the present application. Wherever possible, like reference numerals have been used throughout the drawings to refer to identical or similar parts that perform similar functions.

[0039] In the drawings:

[0040] Figure 1 is a structural schematic diagram of a communication circuit provided by an embodiment of the present application;

[0041] Figure 2 is a structural schematic diagram of another communication circuit provided by an embodiment of the present application;

[0042] Figure 3 is a structural schematic diagram of a first filtering module provided by an embodiment of the present application;

[0043] Figure 4 is a structural schematic diagram of an operational amplification module provided by an embodiment of the present application;

[0044] Figure 5 is a structural schematic diagram of a preprocessing module provided by an embodiment of the present application;

[0045] Figure 6 is a structural schematic diagram of another preprocessing module provided by an embodiment of the present application;

[0046] Figure 7 is a structural schematic diagram of a pre-control module provided by an embodiment of the present application;

[0047] Reference signs: 1, communication interface; 2, preprocessing module; 21, second filter unit; 22, gain unit; 23, overvoltage protection unit; 231, fourth resistor; 232, fifth resistor; 24, overcurrent protection unit; 25, electrostatic protection unit; 251, first capacitor; 252, electrostatic protection diode; 3, analog-to-digital converter; 4, optoelectronic coupling module; 41, transmitter; 42, receiver; 5, control module; 51, power supply unit; 52, transformer; 53, controller; 54, timer; 6, pull-up resistor; 7, first filter module; 71, first diode; 72, second diode; 73, third diode; 74, fourth diode; 75, electrolytic capacitor; 8, operational amplifier module; 81, operational amplifier; 82, first resistor; 83, second resistor; 84, third resistor. DETAILED DESCRIPTION

[0048] Exemplary embodiments of the present application will be described in detail with reference to the drawings. Although exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this application will be thorough and complete, and will fully convey the scope of the application to those skilled in the art.

[0049] The following inventive embodiments can be used to test various control mainboards of household appliances. For example, it can include, but is not limited to, the indoor unit mainboard of an air conditioner, the control mainboard of a juicer, the control mainboard of an electric rice cooker, and the control mainboard of an air fryer, etc., without being limited here.

[0050] Reference Figures 1-7 The inventive embodiments provide a communication circuit, which can include a communication interface 1, a preprocessing module 2, an analog-to-digital converter 3, an optoelectronic coupling module 4, a control module 5, and a pull-up resistor 6, wherein:

[0051] The communication interface 1 is used to be coupled with a test mainboard, the preprocessing module 2 is coupled with the communication interface 1 to adjust the analog voltage outputted by the test mainboard. The analog-digital converter 3 is coupled with the preprocessing module 2 to convert the voltage outputted by the preprocessing module 2 into digital signal. The photoelectric coupling module 4 is coupled with the analog-digital converter 3. The control module 5 is coupled with the photoelectric coupling module 4 to form photoelectric separation between the analog-digital converter 3 and the photoelectric coupling module 4, the input end of the analog-digital converter 3 is coupled with the photoelectric coupling module 4, and the output end of the control module 5 is coupled with the photoelectric coupling module 4. The pull-up resistor 6 is coupled between the control module 5 and the output end of the photoelectric coupling module 4, so that when the control module 5 supplies power to the pull-up resistor 6, the output end of the photoelectric coupling module 4 outputs a digital signal which is proportional to the signal outputted by the analog-digital converter 3.

[0052] In the embodiment of the present application, the preprocessing module 2 refers to the circuit module for adjusting the analog voltage value outputted by the test mainboard before the analog voltage value is converted into digital signal, which can include at least one adjusting unit for causing the change of the analog voltage value outputted by the test mainboard, such as voltage amplification and / or voltage filtering, etc. The analog-digital converter 3 refers to the circuit module for converting analog signal into digital signal, and the control unit can be understood as the circuit module for controlling the output of the digital signal of the analog-digital converter 3. After the analog voltage value is adjusted by the preprocessing module 2, the analog voltage value is converted into corresponding digital signal by the analog-digital converter 3, that is, the analog voltage value in corresponding state can be converted into high level or low level state.

[0053] The photoelectric coupling module 4 is arranged between the control module 5 and the analog-digital converter 3, that is, the input end of the analog-digital converter 3 is coupled with the photoelectric coupling module 4, and the output end of the control module 5 is coupled with the photoelectric coupling module 4. The pull-up resistor 6 is coupled between the control module 5 and the output end of the photoelectric coupling module 4, so that when the control module 5 supplies power to the pull-up resistor 6, the output end of the photoelectric coupling module 4 outputs a digital signal which is proportional to the signal outputted by the analog-digital converter 3.

[0054] Therefore, the corresponding interference signal of the control module 5 in the test mainboard and the communication circuit can be photoelectrically isolated. And the digital signal which is proportional to the analog voltage of the test mainboard can be outputted based on the analog-digital converter 3, so that the parameters and corresponding output responses of the test mainboard in various states can be determined according to the output digital signal. The test influence of the interference signal in the test site on the test mainboard is reduced, and the test accuracy of the test mainboard is improved.

[0055] In an alternative embodiment of the application, referring to Figure 1 and Figure 2 the optoelectronic coupling module 4 comprises a transmitter 41 and a receiver 42, wherein the receiver 42 is coupled to the control module 5 and the transmitter 41 is coupled to the analog-digital converter 3.

[0056] In the embodiment of the application, the transmitter 41 can be a light emitting diode, and the receiver 42 can also be referred to as a light receiver, which can be a photosensitive diode or a photosensitive triode, etc. The optoelectronic coupling module 4 assembles the transmitter 41 and the receiver 42 in the same sealed shell and isolates them from each other with a transparent insulator. Thus, the electrical signal output by the analog-digital converter 3 drives the transmitter 41 to emit light of a certain wavelength, and the receiver 42 receives the light emitted by the transmitter 41 and generates a corresponding photoelectric current. Therefore, in the case that the control module 5 supplies power to the pull-up resistor 6, the transmitter 41, the control module 5, and the pull-up resistor 6 form a power supply loop, and the analog voltage value input by the test mainboard can be detected by detecting the voltage value at the output end of the transmitter 41. Since the input end and the output end of the optoelectronic coupling module 4 are isolated from each other, the electrical signal transmission has the characteristics of unidirectionality, etc., thereby improving the test accuracy of the test mainboard.

[0057] In an alternative embodiment of the application, referring to Figure 2 the circuit further comprises a first filtering module 7 coupled between the pre-processing module 2 and the analog-digital converter 3 to filter the voltage output by the pre-processing module 2.

[0058] In the embodiment of the application, the first filtering module 7 refers to a filtering circuit which can be used to filter the voltage output by the pre-processing module 2. The first filtering module 7 can adopt a capacitor filtering module which can increase the smoothness of the analog voltage output by the pre-processing module 2, thereby reducing the fluctuation of the voltage value output by the pre-processing module 2.

[0059] In an embodiment, referring to Figure 3 the first filtering module 7 can comprise a bridge rectifier unit and an electrolytic capacitor, wherein the bridge rectifier unit is coupled between the pre-processing module and the analog-digital converter. The electrolytic capacitor is coupled between the bridge rectifier unit and the analog-digital converter. Correspondingly, the bridge rectifier unit can comprise a first diode 71, a second diode 72, a third diode 73, a fourth diode 74, and an electrolytic capacitor 75, wherein:

[0060] The negative electrode of the first diode 71 and the positive electrode of the second diode 72 are coupled, and the coupling position of the negative electrode of the first diode 71 and the positive electrode of the second diode 72 serves as the positive input end of the first filter module 7. The positive electrode of the first diode 71 and the positive electrode of the fourth diode 74 are coupled, and the coupling position of the positive electrode of the first diode 71 and the positive electrode of the fourth diode 74 serves as the negative input end of the first filter module 7. The negative electrode of the second diode 72 and the negative electrode of the third diode 73 are coupled, and the coupling position of the negative electrode of the second diode 72 and the negative electrode of the third diode 73 serves as the positive output end of the first filter module 7. The positive electrode of the third diode 73 and the negative electrode of the fourth diode 74 are coupled, and the coupling position of the positive electrode of the third diode 73 and the negative electrode of the fourth diode 74 serves as the negative output end of the first filter module 7. The electrolytic capacitor 75 is connected in parallel to the output end of the first filter module 7, and the anode of the electrolytic capacitor 75 is coupled to the negative electrode of the third diode 73.

[0061] The input end of the first filter module 7 is coupled to the output end of the preprocessing module 2, and the output end of the first filter module 7 is coupled to the analog-to-digital converter 3. After the filtering of the first filter module 7, the average voltage output is increased, and the pulsation is smaller, that is, the smoothness of the analog voltage value is improved.

[0062] In an optional embodiment of the application, the circuit can further include an operational amplifier module 8, the input end of the operational amplifier module 8 is coupled to the preprocessing module 2, and the output end of the operational amplifier module 8 is coupled to the first filter module 7.

[0063] In the embodiment of the application, the operational amplifier module 8 refers to a circuit module that amplifies the input voltage, which can amplify the voltage adjusted by the preprocessing module 2 by a certain multiple. Therefore, in the case that the voltage value output by the preprocessing module 2 is small, which increases the difficulty of processing for the subsequent circuit or cannot drive the subsequent circuit to work, the operational amplifier module 8 linearly amplifies the voltage output by the preprocessing module 2, thereby greatly increasing the voltage value input into the first filter module 7. Thus, the first filter module 7 can further process the circuit according to the linearly amplified voltage.

[0064] In an example, refer to Figure 4As shown, the operation amplification module 8 can include an operation amplifier 81, a first resistor 82, a second resistor 83 and a third resistor 84. Wherein, the positive phase input end of the operation amplifier 81 is coupled with the voltage output end of the preprocessing module 2, one end of the first resistor 82 is grounded, and the other end is coupled with the negative phase input end of the operation amplifier 81, one end of the third resistor 84 is grounded, and the other end is coupled with the output end of the operation amplifier 81, wherein the second resistor 83 is coupled between the negative phase input end of the operation amplifier 81 and the output end of the operation amplifier 81, and the output end of the operation amplifier 81 is coupled with the first filter module 7. Thus, the gain value of the operation amplifier 81 is the ratio of the resistance value of the second resistor 83 to the resistance value of the first resistor 82 plus 1.

[0065] In an alternative embodiment of the application, referring to Figure 6 As shown, the preprocessing module 2 can include a second filter unit 21 and a gain unit 22, wherein the second filter unit 21 is coupled with the communication interface 1 to filter the analog voltage output by the test mainboard. The gain unit 22 is coupled with the second filter unit 21 to adjust the gain of the analog voltage output by the second filter unit 21, wherein the gain unit 22 is coupled with the analog-to-digital converter 3.

[0066] In the embodiment of the application, the second filter unit 21 has the same function as the first filter module 7, and can also filter the analog voltage output by the test mainboard, wherein the circuit structure of the second filter unit 21 can also be the same as that of the first filter module 7. The circuit structure of the gain unit 22 can also be the same as that of the operation method module, so that the filtered analog voltage value can be amplified by the gain unit 22 after being filtered by the second filter unit 21. Thus, the analog voltage value input into the analog-to-digital converter 3 is adjusted to a suitable voltage interval. Wherein, the corresponding voltage gain value can be determined by the person skilled in the art according to the actual design requirements, which is not limited here.

[0067] In an alternative embodiment of the application, referring to Figure 5 As shown, the preprocessing module 2 can also include an overvoltage protection unit 23, which is coupled between the gain unit 22 and the analog-to-digital converter 3.

[0068] In the embodiment of the present application, the overvoltage protection unit 23 refers to a circuit module capable of overvoltage protection of the analog-to-digital converter 3, which can be a voltage dividing circuit, a power supply control circuit or the like, so that the analog voltage value output by the gain unit 22 can be reduced by a certain value and then used as the input analog voltage of the analog-to-digital converter 3, or the power supply control circuit or the like can cut off the coupling loop with the analog-to-digital converter 3 when the voltage is too large. Thus, the situation that the voltage input to the analog-to-digital converter 3 is overvoltage due to the fluctuation of the analog voltage value output by the gain unit 22 can be avoided.

[0069] In an example, referring to FIG. 2, Figure 6 As shown in FIG. 2, the overvoltage protection unit 23 can include a fourth resistor 231 and a fifth resistor 232, one end of the fourth resistor 231 is coupled to one end of the fifth resistor 232, and the coupling position of the fourth resistor 231 and the fifth resistor 232 is used as the positive output end of the overvoltage protection unit 23, the other end of the fifth resistor 232 is used as the negative output end of the overvoltage protection unit 23 and also as the negative input end of the overvoltage protection unit 23. The output end of the overvoltage protection unit 23 is coupled to the input end of the analog-to-digital converter 3, and the other end of the fourth resistor 231 is used as the positive input end of the overvoltage protection unit 23. The input end of the overvoltage protection unit 23 is coupled to the output end of the gain unit 22. Thus, the output voltage value of the overvoltage protection unit 23 is the resistance ratio value and the input voltage value of the overvoltage protection unit 23. The resistance ratio value is the ratio between the resistance value of the fifth resistor 232 and the cumulative sum of the resistance value of the fifth resistor 232 and the resistance value of the fourth resistor 231.

[0070] In an optional embodiment of the present application, the pre-processing module 2 can further include an overcurrent protection unit 24 coupled between the gain unit 22 and the analog-to-digital converter 3.

[0071] In the embodiment of the present application, the overcurrent protection unit 24 refers to a circuit module capable of overcurrent protection of the analog-to-digital converter 3, which can be a current dividing circuit or a fuse or the like. For example, the current value output by the gain unit 22 can be reduced by a certain value and then used as the input current of the analog-to-digital converter 3, or the fuse such as a fuse or the like can cut off the coupling loop with the analog-to-digital converter 3 when the current value output by the gain unit 22 is too large. Thus, the situation that the current input to the analog-to-digital converter 3 is overcurrent due to the fluctuation of the current value output by the gain unit 22 can be avoided.

[0072] In an example, when the overcurrent protection unit 24 is a fuse, the fuse can be coupled between the positive output end of the gain unit 22 and the positive input end of the analog-to-digital converter 3.

[0073] In an optional embodiment of the application, the pre-processing module 2 can further comprise an electro-static protection unit 25 coupled between the gain unit 22 and the analog-to-digital converter 3.

[0074] In an embodiment of the application, the electro-static protection unit 25 refers to a circuit module capable of providing electro-static protection for the analog-to-digital converter 3. For example, as shown in Figure 6 the electro-static protection unit 25 can comprise a first capacitor 251 and an electro-static protection diode 252, wherein one end of the first capacitor 251 and the negative pole of the electro-static protection diode 252 are respectively coupled to the positive input end of the analog-to-digital converter 3 and the positive output end of the gain unit 22. The other end of the first capacitor 251 and the positive pole of the electro-static protection diode 252 are respectively coupled to the negative input end of the analog-to-digital converter 3 and the negative output end of the gain unit 22. In other embodiments, the electro-static protection unit 25 can also be coupled between the over-current protection unit 24 and the analog-to-digital converter 3. Alternatively, the electro-static protection unit 25 can also be coupled between the over-voltage protection unit 23 and the analog-to-digital converter 3.

[0075] Therefore, the first capacitor 251 and the electro-static protection diode 252 form the electro-static protection unit 25 (Electro-Static discharge, ESD) for providing electro-static protection for the analog-to-digital converter 3.

[0076] In an optional embodiment of the application, the communication interface 1 is one of the following: a USB interface, an RS232 interface and an RS485 interface.

[0077] In an embodiment of the application, in order to improve the product applicability of the communication circuit or the mainboard testing device, the communication interface 1 is applicable to various testing mainboards corresponding to the communication interface 1, and the communication interface 1 can be a USB (Universal Serial Bus, Universal Serial Bus) interface. In some embodiments, the communication interface 1 can also be an RS232 (Recommended Standard 232, Recommended Standard 232) interface. In some embodiments, the communication interface can also be an RS485 (Recommended Standard 485, Recommended Standard 485) interface, etc.

[0078] In an optional embodiment of the application, referring to Figure 7As shown, the control module 5 can include a power supply unit 51, a transformer 52 coupled with the power supply unit 51, and a controller 53 coupled with the transformer 52, etc. The power supply unit 51 is configured to provide working power for the mainboard testing device, the transformer 52 is configured to step down or step up the voltage value output by the power supply unit 51, so that the voltage value output by the transformer 52 can be used for working of the controller 53. The controller 53 is coupled with the pull-up resistor 6, so as to control the current flowing into the pull-up resistor 6 by the controller 53. When the control module 5 supplies power to the pull-up resistor 6, the output end of the optoelectronic coupling module 4 outputs a digital signal proportional to the signal output by the analog-to-digital converter 3. The controller 53 can be a single-chip microcomputer or a processor, etc.

[0079] In some other embodiments, the control module 5 can further include a timer 54 coupled with the controller 53, configured to reset the control module 5 by the timer 54.

[0080] The embodiment of the application further provides a mainboard testing device, which can include the communication circuit according to any one of the above-mentioned embodiments.

[0081] In summary, the embodiment of the application discloses a communication circuit and a mainboard testing device. The communication circuit can include a communication interface 1, a preprocessing module 2, an analog-to-digital converter 3, an optoelectronic coupling module 4, a control module 5, and a pull-up resistor 6. The communication interface 1 is configured to be coupled with a test mainboard, the preprocessing module 2 is coupled with the communication interface 1, so as to adjust the analog voltage output by the test mainboard. The analog-to-digital converter 3 is coupled with the preprocessing module 2, so as to perform analog-to-digital conversion on the voltage output by the preprocessing module 2. The optoelectronic coupling module 4 is coupled with the analog-to-digital converter 3. The control module 5 is coupled with the optoelectronic coupling module 4, so as to form photoelectric separation between the analog-to-digital converter 3 and the optoelectronic coupling module 4. The input end of the analog-to-digital converter 3 is coupled with the optoelectronic coupling module 4, and the output end of the control module 5 is coupled with the optoelectronic coupling module 4. The pull-up resistor 6 is coupled between the control module 5 and the output end of the optoelectronic coupling module 4, so that when the control module 5 supplies power to the pull-up resistor 6, the output end of the optoelectronic coupling module 4 outputs a digital signal proportional to the signal output by the analog-to-digital converter 3. In this way, the corresponding interference signals of the test mainboard and the control module 5 in the communication circuit can be photoelectrically isolated, the influence of the interference signals in the test site on the test of the test mainboard is reduced, and the test accuracy of the test mainboard is improved.

[0082] Each of the embodiments described in this specification has at least one implementation in one or more systems and methods that include the features described herein. Each of the embodiments described in this specification can be used alone or in combination with one another.

[0083] Any combination of the described embodiments in this specification is considered to be within the scope of the application, to the extent that the individual features are not mutually inconsistent, as would be understood by one of ordinary skill in the art. Embodiments of the application are intended to embrace all such alterations, modifications, and variations that fall within the scope of the application. Accordingly, the application includes both combinations and sub-combinations of the embodiments described herein.

[0084] In this specification, numerous specific details are set forth to provide a thorough understanding of various embodiments of the application. However, it will be understood by those skilled in the art that the embodiments of the application can be practiced without some or all of the specific details set forth herein. In some instances, well-known methods, structures and techniques have not been shown or described in detail in order to not obscure the understanding of this description.

[0085] Similarly, it is to be understood that the embodiments of the application can be used alone or in combination with one another.

[0086] Further, those skilled in the art will appreciate that the features described herein are capable of being combined with other features described herein without departing from the scope of the present application. For example, the disclosure of one embodiment does not preclude the disclosure of another embodiment having the same or similar features.

Claims

1. A communication circuit, characterized in that, The circuit includes: Communication interface (1), the communication interface (1) is used to be coupled to the test motherboard; A preprocessing module (2) is coupled to the communication interface (1) to adjust the analog voltage output by the test motherboard; Analog-to-digital converter (3), which is coupled to the preprocessing module (2) to convert the voltage output by the preprocessing module (2) into an analog-to-digital converter; An optocoupler module (4) is coupled to the analog-to-digital converter (3); A control module (5) is coupled to the optocoupler module (4) to form optocoupler separation between the analog-to-digital converter (3) and the optocoupler module (4), wherein the analog-to-digital converter (3) is coupled to the input terminal of the optocoupler module (4), and the control module (5) is coupled to the output terminal of the optocoupler module (4); Pull-up resistor (6) is coupled between the output terminal of the control module (5) and the optocoupler module (4) so ​​that when the control module (5) supplies power to the pull-up resistor (6), the output terminal of the optocoupler module (4) outputs a digital signal that is proportional to the signal output by the analog-to-digital converter (3); The preprocessing module (2) includes: a second filtering unit (21), which is coupled to the communication interface (1) to filter the analog voltage output by the test motherboard; and a gain unit (22), which is coupled to the second filtering unit (21) to adjust the gain of the analog voltage output by the second filtering unit (21), wherein the gain unit (22) is coupled to the analog-to-digital converter (3). The circuit also includes a first filtering module (7), which is coupled between the preprocessing module (2) and the analog-to-digital converter (3) to filter the voltage output by the preprocessing module (2).

2. The communication circuit according to claim 1, characterized in that, The optocoupler module (4) includes a transmitter (41) and a receiver (42), wherein the receiver (42) is coupled to the control module (5) and the transmitter (41) is coupled to the analog-to-digital converter (3).

3. The communication circuit according to claim 1, characterized in that, The first filtering module (7) includes: A bridge rectifier unit is coupled between the preprocessing module (2) and the analog-to-digital converter (3); An electrolytic capacitor (75) is coupled between the bridge rectifier unit and the analog-to-digital converter (3).

4. The communication circuit according to claim 3, characterized in that, The bridge rectifier unit includes: First diode (71); The second diode (72) has its positive terminal coupled to the negative terminal of the first diode (71), and the coupling point is coupled to the positive output terminal of the preprocessing module (2). The third diode (73) has its cathode coupled to the cathode of the second diode (72), and the coupling point is coupled to the positive input terminal of the analog-to-digital converter (3). The fourth diode (74) has its cathode coupled to the anode of the third diode (73), and the coupling point is coupled to the negative output terminal of the preprocessing module (2); wherein, The positive terminal of the first diode (71) is coupled to the positive terminal of the fourth diode (74), and the coupling point is coupled to the negative input terminal of the analog-to-digital converter (3). Furthermore, the electrolytic capacitor (75) is connected in parallel to the input terminal of the analog-to-digital converter (3), and the anode of the electrolytic capacitor (75) is coupled to the negative terminal of the third diode (73).

5. The communication circuit according to claim 1, characterized in that, The circuit also includes an operational amplifier module (8), the input of which is coupled to the preprocessing module (2), and the output of which is coupled to the first filtering module (7).

6. The communication circuit according to claim 5, characterized in that, The operational amplifier module (8) includes: Operational amplifier (81), the non-inverting input terminal of the operational amplifier (81) is coupled to the positive output terminal of the preprocessing module (2), wherein the output terminal of the operational amplifier (81) is coupled to the first filtering module (7); The first resistor (82) has one end coupled to the negative inverting input terminal of the operational amplifier (81) and the other end grounded. The second resistor (83) is coupled between the negative input terminal of the operational amplifier (81) and the output terminal of the operational amplifier (81); The third resistor (84) has one end coupled to the output terminal of the operational amplifier (81) and the other end grounded.

7. The communication circuit according to claim 1, characterized in that, The preprocessing module (2) further includes an overvoltage protection unit (23), which is coupled between the gain unit (22) and the analog-to-digital converter (3).

8. The communication circuit according to claim 1, characterized in that, The preprocessing module (2) further includes an overcurrent protection unit (24), which is coupled between the gain unit (22) and the analog-to-digital converter (3).

9. The communication circuit according to claim 1, characterized in that, The preprocessing module (2) further includes an electrostatic protection unit (25), which is coupled between the gain unit (22) and the analog-to-digital converter (3).

10. The communication circuit according to claim 1, characterized in that, The communication interface (1) is one of the following: USB interface, RS232 interface and RS485 interface.

11. A motherboard testing device, characterized in that, The device includes the communication circuit as described in any one of claims 1-10.

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