Interface circuit and electronic device

Abstract

The application provides an interface circuit and an electronic device. The interface circuit comprises a comparison module configured to output a first switching signal when a common-mode voltage of a differential input signal is less than a preset voltage, and output a second switching signal when the common-mode voltage of the differential input signal is not less than the preset voltage. A negative voltage generation module is configured to output a negative voltage according to the first switching signal, and output a ground voltage according to the second switching signal. An amplification module is configured to amplify the differential input signal according to the negative voltage or the ground voltage. A conversion module is configured to convert the differential input signal into a digital signal as an output of the interface circuit. When the common-mode voltage of the differential input signal is less than the preset voltage, the negative voltage generation module outputs the negative voltage as a reference potential end of the amplification module, thereby improving the common-mode equivalent voltage value of the differential input signal at the input end of the amplification module, so that the differential input signal is stable in gain and low in power consumption during high-speed transmission, and can accurately transmit data.

Description

Technical Field

[0001] This application belongs to the field of interface technology, and in particular relates to an interface circuit and electronic device. Background Technology

[0002] With the continuous development of technology, the data transmission rate between different electronic devices or equipment is getting faster and faster. In order to accurately transmit high-speed signals between different electronic devices or equipment, high-speed interface circuits are generally required at the ports of the electronic devices or equipment.

[0003] Traditional high-speed interface circuits typically amplify and transmit differential input signals directly. However, when the common-mode voltage of the differential input signal is low, gain attenuation can easily occur during transmission, leading to problems such as inaccurate data transmission. Utility Model Content

[0004] The purpose of this application is to provide an interface circuit and electronic device that aims to solve the problem that traditional high-speed interface circuits cannot accurately transmit data when the common-mode voltage of differential input signals is low.

[0005] To achieve the above objectives, in a first aspect, embodiments of this application provide an interface circuit, including a comparison module, a negative voltage generation module, an amplification module, and a conversion module. The comparison module is used to output a first switching signal when the common-mode voltage of the differential input signal is less than a preset voltage, and to output a second switching signal when the common-mode voltage of the differential input signal is not less than the preset voltage. The negative voltage generation module is connected to the comparison module and is used to output a negative voltage according to the first switching signal, and also to output a ground voltage according to the second switching signal. The input terminal of the amplification module serves as the input terminal of the interface circuit to receive the differential input signal. The reference potential terminal of the amplification module is connected to the negative voltage generation module, and the amplification module is used to amplify the differential input signal according to the negative voltage or the ground voltage. The conversion module is connected to the output terminal of the amplification module and is used to convert the differential input signal into a digital signal for use as the output of the interface circuit.

[0006] In another possible implementation of the first aspect, the comparison module is further configured to output a first switching signal when the common-mode voltage of the differential input signal is less than a first preset voltage; and output a second switching signal when the common-mode voltage of the differential input signal is greater than a second preset voltage; wherein the second preset voltage is greater than the first preset voltage.

[0007] In another possible implementation of the first aspect, the comparison module includes multiple comparison units and a reference voltage generation unit. The multiple comparison units include various comparison voltages, arranged sequentially by magnitude. When the common-mode voltage of the differential input signal is less than one of the comparison voltages, the multiple comparison units output a corresponding comparison result signal; when the common-mode voltage of the differential input signal is not less than any of the comparison voltages, they output a second switching signal. The reference voltage generation unit is connected to both the multiple comparison units and the negative voltage generation module. The reference voltage generation unit outputs a corresponding reference voltage based on the comparison result signal to adjust the negative voltage of the negative voltage generation module.

[0008] In another possible implementation of the first aspect, the negative pressure generating module includes a switching unit, a negative pressure pump unit, and a grounding unit. The switching unit is connected to the comparison module, the negative pressure pump unit, and the grounding unit respectively. The switching unit is used to connect the path between the comparison module and the negative pressure pump unit according to a first switching signal, and also to connect the path between the comparison module and the grounding unit according to a second switching signal.

[0009] In another possible implementation of the first aspect, the amplification module includes multiple amplification units. These multiple amplification units are connected in series and are all connected to the negative voltage generation module. The multiple amplification units are used to amplify the differential input signal in multiple stages.

[0010] In another possible implementation of the first aspect, the interface circuit further includes a first resistor and a second resistor. The first terminal of the first resistor and the first terminal of the second resistor are both connected to the comparator module. The second terminal of the first resistor and the first input terminal of the first-stage amplification unit in the plurality of amplification units are both connected to the first terminal of the differential input signal. The second terminal of the second resistor and the second input terminal of the first-stage amplification unit in the plurality of amplification units are both connected to the second terminal of the differential input signal.

[0011] In another possible implementation of the first aspect, the amplification unit includes a current source, a first MOSFET, a second MOSFET, a third resistor, and a fourth resistor. The input terminal of the current source is connected to a power supply, and the output terminal of the current source is connected to the source of the first MOSFET and the source of the second MOSFET, respectively. The drain of the first MOSFET is grounded through the third resistor, and the gate of the first MOSFET is connected to the first terminal of the differential input signal. The drain of the second MOSFET is grounded through the fourth resistor, and the gate of the second MOSFET is connected to the second terminal of the differential input signal.

[0012] In another possible implementation of the first aspect, the amplification unit further includes an impedance matching component, which is connected to the gate of the first MOS transistor and the gate of the second MOS transistor, respectively.

[0013] In another possible implementation of the first aspect, the conversion module includes a third MOSFET, a fourth MOSFET, a fifth MOSFET, a sixth MOSFET, a seventh MOSFET, an eighth MOSFET, a ninth MOSFET, and a tenth MOSFET. The gate of the third MOSFET is connected to the second terminal of the differential input signal and grounded through the fourth MOSFET; the gate of the fifth MOSFET is connected to the first terminal of the differential input signal and grounded through the sixth MOSFET, and the gates of the fourth and sixth MOSFETs are connected. The drain of the fifth MOSFET is connected to the gates of the seventh and eighth MOSFETs respectively, the drain of the seventh MOSFET is grounded through the eighth MOSFET and connected to the gates of the ninth and tenth MOSFETs respectively, and the drain of the ninth MOSFET is grounded through the tenth MOSFET and outputs a digital signal.

[0014] Secondly, embodiments of this application provide an electronic device including the interface circuit described in any of the above claims.

[0015] In this embodiment, a comparison module is used to determine the magnitude of the common-mode voltage of the differential input signal. When the common-mode voltage of the differential input signal is less than the preset voltage, a negative voltage is output by the negative voltage generation module and used as the reference potential terminal of the amplification module. This increases the common-mode equivalent voltage value of the differential input signal at the input terminal of the amplification module, thereby ensuring stable gain, low power consumption, and accurate data transmission during high-speed transmission of the differential input signal. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of an interface circuit provided in an embodiment of this application;

[0018] Figure 2 A circuit diagram of an interface circuit provided in an embodiment of this application;

[0019] Figure 3 A circuit diagram of an interface circuit provided in another embodiment of this application;

[0020] Figure 4 A circuit diagram of an amplification unit of an interface circuit provided in an embodiment of this application;

[0021] Figure 5 A circuit diagram of an amplification unit for an interface circuit provided in another embodiment of this application;

[0022] Figure 6 This is a circuit diagram of a conversion module for an interface circuit provided in an embodiment of this application. Detailed Implementation

[0023] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0025] Currently, traditional high-speed interface circuits typically amplify and transmit differential input signals directly. However, the transmission of differential input signals presents challenges such as high speed, small differential signal size, and a large common-mode signal variation range. Particularly when the common-mode voltage of the differential input signal is low, gain attenuation can easily occur during transmission, leading to inaccurate data transmission. While adding an additional amplifier can address the low common-mode voltage issue, high-speed interface circuits generally have high current requirements and high power consumption. Furthermore, adding an amplifier is equivalent to increasing the overall gain, which may result in differences in data transmission for different differential input signal common-mode voltages, leading to inferior signal quantization performance compared to signals with stable gain.

[0026] To address this, this application provides an interface circuit that, when the common-mode voltage of the differential input signal is less than a preset voltage, outputs a negative voltage through a negative voltage generation module and uses it as a reference potential terminal of the amplification module. This increases the common-mode equivalent voltage value of the differential input signal at the input terminal of the amplification module, thereby ensuring stable gain, low power consumption, and accurate data transmission of the differential input signal during high-speed transmission.

[0027] The interface circuit provided in this application will be described in illustrative terms below with reference to the accompanying drawings.

[0028] Figure 1 This is a schematic diagram of the structure of an interface circuit provided in an embodiment of this application. Figure 1As shown, by way of example, this application provides an interface circuit 10. The interface circuit 10 includes a comparison module 101, a negative voltage generation module 102, an amplification module 103, and a conversion module 104. The comparison module 101 is used to output a first switching signal when the common-mode voltage of the differential input signal is less than a preset voltage; and to output a second switching signal when the common-mode voltage of the differential input signal is not less than the preset voltage. The negative voltage generation module 102 is connected to the comparison module 101, and is used to output a negative voltage according to the first switching signal, and also to output a ground voltage according to the second switching signal. The input terminal of the amplification module 103 serves as the input terminal of the interface circuit 10 to receive the differential input signal. The reference potential terminal of the amplification module 103 is connected to the negative voltage generation module 102, and the amplification module 103 is used to amplify the differential input signal according to the negative voltage or the ground voltage. The conversion module 104 is connected to the output terminal of the amplification module 103, and the conversion module 104 is used to convert the differential input signal into a digital signal as the output of the interface circuit 10.

[0029] In this embodiment, when a differential input signal needs to be transmitted, the common-mode voltage of the differential input signal is first compared with a preset voltage by the comparison module 101. When the common-mode voltage of the differential input signal is less than the preset voltage, a first switching signal is output; when the common-mode voltage of the differential input signal is not less than the preset voltage, a second switching signal is output and sent to the negative voltage generation module 102. Then, the negative voltage generation module 102 outputs a negative voltage according to the first switching signal, or outputs a ground voltage according to the second switching signal, as a ground potential reference voltage for the amplification module 103. Then, the amplification module 103 obtains a differential output signal that meets the requirements of high-speed transmission based on the negative voltage or the ground voltage, and amplifies the differential input signal. Finally, the conversion module 104 converts the differential input signal into a digital signal for subsequent processing. This ensures that the differential input signal has stable gain, low power consumption, and accurate data transmission during high-speed transmission.

[0030] Figure 2 This is a circuit diagram of an interface circuit provided in an embodiment of this application. Figure 2 As shown, exemplarily, in one embodiment provided in this application, the comparison module 101 may include two preset voltages, namely a first preset voltage Vref_l and a second preset voltage Vref_h. The voltage value of the second preset voltage Vref_h is greater than the voltage value of the first preset voltage Vref_l.

[0031] The comparison module 101 is used to output a first switching signal to control the negative voltage generation module 102 to generate a negative voltage (e.g., -0.2V) when the common-mode voltage of the differential input signal is less than the first preset voltage Vref_l, indicating that the common-mode voltage of the differential input signal is too small and cannot accurately transmit data. This ensures that the common-mode equivalent voltage of the differential input signal of the amplification module 103 is large enough, and the source-drain voltage Vds of the input pair transistors of the amplifier in the amplification module 103 is large enough to operate in the saturation region, maintain the total gain unchanged, and thus enable accurate data transmission.

[0032] The comparison module 101 is also used to determine if the common-mode voltage of the differential input signal is greater than the second preset voltage Vref_h. This indicates that the common-mode voltage of the differential input signal is sufficiently large to meet the normal operation requirements of the amplifier module 103 and can accurately transmit data. Therefore, it outputs a second switching signal to control the negative voltage generation module 102 to output a ground voltage (e.g., 0V), enabling the common-mode equivalent voltage value of the differential input signal of the amplifier module 103 to accurately transmit data. For example, the second switching signal is the opposite of the first switching signal.

[0033] It should be understood that since the negative voltage is generated by the negative voltage generation module 102, its voltage stability is generally lower than that of the ground power supply. Therefore, when the common-mode voltage of the differential input signal is greater than the second preset voltage Vref_h, the comparison module 101 switches the ground power supply to analog ground (AGND), which can ensure the stability of the ground potential and reduce the introduction of noise.

[0034] It should be noted that the comparison module 101 is also used to maintain the original switching signal when the common-mode voltage of the differential input signal is greater than the first preset voltage Vref_l and less than the second preset voltage Vref_h, thereby adding a hysteresis function to the comparison module 101 and preventing frequent switching of the negative voltage of the interface circuit.

[0035] like Figure 2 As shown, exemplarily, in another embodiment provided in this application, the negative pressure generating module 102 may include a switching unit 1021, a negative pressure pump unit 1022, and a grounding unit 1023. The switching unit 1021 is connected to the comparison module 101, the negative pressure pump unit 1022, and the grounding unit 1023, respectively. The switching unit 1021 is used to connect the path between the comparison module 101 and the negative pressure pump unit 1022 according to a first switching signal, and is also used to connect the path between the comparison module 101 and the grounding unit 1023 according to a second switching signal.

[0036] For example, the switching unit 1021 can be a switching MOSFET.

[0037] In this embodiment, when the switching unit 1021 receives the first switching signal, it opens the path between the comparison module 101 and the negative pressure pump unit 1022 so that the negative voltage of the negative pressure pump unit 1022 is used as the reference voltage of the amplification module 103, thereby increasing the common-mode equivalent voltage value at the input terminal of the amplification module 103 and ensuring that the amplification module 301 can accurately amplify and transmit data.

[0038] When the switching unit 1021 receives the second switching signal, it opens the path between the comparison module 101 and the grounding unit 1023 so that the grounding power supply 1023 can provide grounding voltage to the amplification module 103, thereby enabling the amplification module 103 to amplify and transmit data according to the original common-mode equivalent voltage value of the differential input signal.

[0039] like Figure 2 As shown, exemplarily, in another embodiment provided in this application, the amplification module 103 includes a plurality of amplification units 1031. The plurality of amplification units 1031 are connected in series and are all connected to the negative pressure generation module 102. The plurality of amplification units 1031 are used to amplify the differential input signal in multiple stages.

[0040] In this embodiment, the amplification module 103 may include one or more amplification units 1031 to amplify the differential input signal in one or more stages. It should be noted that the amplification module 103 is equipped with multiple amplification units 1031 to meet the requirements of high-speed signal transmission. Since the amplifier circuit has a large bandwidth but relatively small gain, two or more stages of amplifiers can be connected in series to ensure that the overall gain of the entire link meets the requirements.

[0041] like Figure 2 As shown, exemplarily, in another embodiment provided in this application, the interface circuit 10 further includes a first resistor R1 and a second resistor R2. The first end of the first resistor R1 and the first end of the second resistor R2 are both connected to the comparison module 101. The second end of the first resistor R1 and the first input end of the first stage amplification unit in the plurality of amplification units 1031 are all connected to the first end of the differential input signal. The second end of the second resistor R2 and the second input end of the first stage amplification unit in the plurality of amplification units 1031 are all connected to the second end of the differential input signal.

[0042] In this embodiment, the first resistor R1 and the second resistor R2 form a voltage divider resistor to divide the voltage value of the differential input signal, thereby obtaining the common-mode voltage Vcm of the differential input signal, and sending it to the input terminal of the comparison module 101.

[0043] It should be noted that the resistance value of the first resistor R1 is equal to the resistance value of the second resistor R2.

[0044] Figure 3This is a circuit diagram of another interface circuit provided in this application. For example... Figure 3 As shown, exemplarily, the comparison module 101 may include multiple comparison units 1011 and a reference voltage generation unit 1012. The multiple comparison units 1011 include various comparison voltages, arranged sequentially in order of magnitude. When the common-mode voltage of the differential input signal is less than one of the multiple comparison voltages, the multiple comparison units output a corresponding comparison result signal; when the common-mode voltage of the differential input signal is not less than any of the multiple comparison voltages, they output a second switching signal. The reference voltage generation unit 1012 is connected to both the multiple comparison units 1011 and the negative voltage generation module 102. The reference voltage generation unit 1012 is used to output a corresponding reference voltage based on the comparison result signal to adjust the negative voltage of the negative voltage generation module 102.

[0045] In this embodiment, the comparison module 101 may include multiple comparison units 1011, each comparison unit 1011 having a comparison voltage, and the comparison units 1011 corresponding to the multiple comparison voltages are arranged sequentially according to the voltage magnitude. When the comparison module 101 receives the common-mode voltage of the differential input signal, it compares the common-mode voltage of the differential input signal with the comparison voltages of the multiple comparison units 1011 sequentially. When the common-mode voltage of the differential input signal is less than one of the multiple comparison voltages, the corresponding comparison result signal is output. For example, the comparison result signal can be a binary signal 111000, where "1" indicates that the common-mode voltage of the differential input signal is less than the comparison voltage, and "0" indicates that the common-mode voltage of the differential input signal is greater than the comparison voltage.

[0046] Meanwhile, when the common-mode voltage of the differential input signal is not less than any of the various comparison voltages, it indicates that the common-mode voltage of the differential input signal is large and can accurately transmit data. In this case, the second switching signal is directly output, and the original positive and negative voltage difference of the differential input signal is used as the input voltage of the amplification module 103.

[0047] Then, the reference voltage generation unit 1012 outputs a corresponding reference voltage based on the comparison result signals of multiple comparison units 1011. For example, the reference voltage can be -0.1V, -0.2V, -0.3V, etc., so that the negative voltage generation module 102 outputs a corresponding negative voltage based on the reference voltage, which serves as the reference voltage for the amplification module 103, thereby increasing the common-mode equivalent voltage value of the differential input signal of the amplification module 103.

[0048] For example, the comparison unit 1011 can be a comparator, and multiple comparison units 1011 can form a comparator array. This allows the comparator array to select a suitable ground potential reference value for the current common-mode voltage based on the level of the common-mode voltage of different differential input signals, ensuring that the equivalent ground potential is the same under different common-mode voltages.

[0049] Figure 4 This is a circuit diagram of an amplification unit of an interface circuit provided in an embodiment of this application. Figure 4 As shown, exemplarily, the amplification unit 1031 includes a current source A1, a first MOSFET M1, a second MOSFET M2, a third resistor R3, and a fourth resistor R4. The input terminal of the current source A1 is connected to a power supply, and the output terminal of the current source A1 is connected to the source of the first MOSFET M1 and the source of the second MOSFET M2, respectively. The drain of the first MOSFET M1 is grounded through the third resistor R3, and the gate of the first MOSFET M1 is connected to the first terminal vinn of the differential input signal. The drain of the second MOSFET M2 is grounded through the fourth resistor R4, and the gate of the second MOSFET M2 is connected to the second terminal vinn of the differential input signal.

[0050] In this embodiment, the amplification unit 1031 acts as a differential amplifier, with the third resistor R3 and the fourth resistor R4 serving as loads. When the common-mode voltage of the differential input signal is low (e.g., 70mV), the input gate voltage of the amplification unit 1031 or the first-stage amplifier is low, while the current source A1 remains constant. Its drain-source voltage Vds is determined by the amplifier's static bias, making it difficult to ensure the input transistors operate in the saturation region. This ultimately leads to a gain attenuation in the amplification unit 1031 or the first-stage amplifier, or even a gain less than 1, making it difficult to maintain sufficient total gain and causing signal transmission errors. Therefore, the negative voltage generation module 102 is needed to generate a negative voltage as a reference voltage for the amplification unit 1031 or the first-stage amplifier to increase the common-mode equivalent voltage value of the differential input voltage of the amplification unit 1031 or the first-stage amplifier, ensuring sufficient total gain and thus accurately transmitting the data signal.

[0051] Figure 5 This is a circuit diagram of an amplification unit for an interface circuit provided in another embodiment of this application. (See diagram below.) Figure 5 As shown, by way of example, the input terminal of the first-stage amplification unit 1031 among the plurality of amplification units 1031 is also electrically connected to an impedance matching component, which is connected to the gate of the first MOS transistor M1 and the gate of the second MOS transistor M2, respectively.

[0052] In this embodiment, the impedance matching component may include two impedance matching resistors Z. ID / 2, Two MOSFETs and one capacitor C CM An impedance matching resistor Z is connected in series at the first input terminal of the differential amplifier. ID / 2, a MOSFET and a capacitor C CM After grounding, another impedance matching resistor Z is connected in series at the second input terminal of the differential amplifier. ID / 2, another MOSFET and the aforementioned capacitor C CM Then grounded. This is achieved through two impedance matching resistors Z.ID / 2, Two MOSFETs and one capacitor C CM As the matching impedance of the amplification unit 1031, it ensures that the input signal can be effectively transmitted to the internal circuit of the amplifier, and will not cause reflection or signal attenuation due to impedance mismatch.

[0053] It should be noted that, in order to address the issue of low common-mode voltage in differential input signals, a PMOS transistor can be used as the input transistor in the amplifier.

[0054] Figure 6 This is a circuit diagram of a conversion module for an interface circuit provided in an embodiment of this application. Figure 6 As shown, exemplarily, in one embodiment provided in this application, the conversion module 104 includes a third MOSFET M3, a fourth MOSFET M4, a fifth MOSFET M5, a sixth MOSFET M6, a seventh MOSFET M7, an eighth MOSFET M8, a ninth MOSFET M9, and a tenth MOSFET M10. The gate of the third MOSFET M3 is connected to the second terminal of the differential input signal and grounded through the fourth MOSFET M4. The gate of the fifth MOSFET M5 is connected to the first terminal of the differential input signal (e.g., outn2) and grounded through the sixth MOSFET M6. The gate of the fourth MOSFET M4 is connected to the gate of the sixth MOSFET M6. The drain of the fifth MOSFET M5 is connected to the gates of the seventh MOSFET M7 and the eighth MOSFET M8, respectively. The drain of the seventh MOSFET M7 is grounded through the eighth MOSFET M8 and connected to the gates of the ninth MOSFET M9 and the tenth MOSFET M10, respectively. The drain of the ninth MOSFET M9 is grounded through the tenth MOSFET M10 and outputs a digital signal.

[0055] In this embodiment, the gate of the third MOSFET M3 can be connected to the second terminal (e.g., outp2) of the differential output signal of the last stage in the multi-stage amplification unit. The gate of the fifth MOSFET M5 can be connected to the first terminal (e.g., outn2) of the differential output signal of the last stage in the multi-stage amplification unit. Thus, the differential input signal is converted into a digital signal through the third to tenth MOSFETs and used as the output of the entire interface circuit (e.g., out). In other words, the conversion module 104 is used to convert the dual-ended differential output signal into a single-ended digital signal.

[0056] For example, an embodiment of this application provides an electronic device including an interface circuit 10.

[0057] In this embodiment, the interface circuit 10 is located inside the electronic device. A comparison module is used to determine the magnitude of the common-mode voltage of the differential input signal. When the common-mode voltage of the differential input signal is less than the preset voltage, a negative voltage is output by the negative voltage generation module and used as the reference potential terminal of the amplification module. This increases the common-mode equivalent voltage value of the differential input signal at the input terminal of the amplification module, thereby ensuring stable gain, low power consumption, and accurate data transmission during high-speed transmission of the differential input signal.

[0058] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0059] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above-described electronic device can be referred to the corresponding process in the foregoing embodiments, and will not be repeated here.

[0060] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0061] Those skilled in the art will recognize that the units of the various examples described in connection with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0062] In the embodiments provided in this application, it should be understood that the disclosed interface circuits can be implemented in other ways. For example, the interface circuit embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another electronic device, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some multi-interface electronic devices, apparatuses, or units, and may be electrical, mechanical, or other forms.

[0063] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0064] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0065] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. An interface circuit, characterized in that, It includes a comparison module, a negative pressure generation module, an amplification module, and a conversion module; The comparison module is configured to output a first switching signal when the common-mode voltage of the differential input signal is less than a preset voltage, and output a second switching signal when the common-mode voltage of the differential input signal is not less than the preset voltage. The negative voltage generating module is connected to the comparison module. The negative voltage generating module is used to output a negative voltage according to the first switching signal and also to output a ground voltage according to the second switching signal. The input terminal of the amplification module serves as the input terminal of the interface circuit to receive the differential input signal. The reference potential terminal of the amplification module is connected to the negative voltage generation module. The amplification module is used to amplify the differential input signal according to the negative voltage or the ground voltage. The conversion module is connected to the output terminal of the amplification module, and the conversion module is used to convert the differential input signal into a digital signal as the output of the interface circuit.

2. The interface circuit as described in claim 1, characterized in that, The comparison module is further configured to output the first switching signal when the common-mode voltage of the differential input signal is less than a first preset voltage; and to output the second switching signal when the common-mode voltage of the differential input signal is greater than a second preset voltage. The second preset voltage is greater than the first preset voltage.

3. The interface circuit as described in claim 1, characterized in that, The comparison module includes multiple comparison units and a reference voltage generation unit; The plurality of comparison units include a plurality of comparison voltages, which are arranged in order of magnitude; when the common-mode voltage of the differential input signal is less than one of the plurality of comparison voltages, the plurality of comparison units output a corresponding comparison result signal; when the common-mode voltage of the differential input signal is not less than any of the plurality of comparison voltages, the plurality of comparison units output a second switching signal. The reference voltage generating unit is connected to the plurality of comparison units and the negative voltage generating module respectively. The reference voltage generating unit is used to output a corresponding reference voltage according to the comparison result signal, so as to adjust the negative voltage of the negative voltage generating module.

4. The interface circuit as described in any one of claims 1 to 3, characterized in that, The negative pressure generating module includes a switching unit, a negative pressure pump unit, and a grounding unit; The switching unit is connected to the comparison module, the negative pressure pump unit and the grounding unit respectively. The switching unit is used to connect the path between the comparison module and the negative pressure pump unit according to the first switching signal, and is also used to connect the path between the comparison module and the grounding unit according to the second switching signal.

5. The interface circuit as described in any one of claims 1 to 3, characterized in that, The amplification module includes multiple amplification units; The plurality of amplification units are connected in series and are all connected to the negative pressure generating module. The plurality of amplification units are used to amplify the differential input signal in multiple stages.

6. The interface circuit as described in claim 5, characterized in that, The interface circuit also includes a first resistor and a second resistor. The first end of the first resistor and the first end of the second resistor are both connected to the comparison module. The second end of the first resistor and the first input end of the first stage amplification unit in the plurality of amplification units are both connected to the first end of the differential input signal. The second end of the second resistor and the second input end of the first stage amplification unit in the plurality of amplification units are both connected to the second end of the differential input signal.

7. The interface circuit as described in claim 5, characterized in that, The amplification unit includes a current source, a first MOS transistor, a second MOS transistor, a third resistor, and a fourth resistor; The input terminal of the current source is connected to a power supply, and the output terminal of the current source is connected to the source of the first MOS transistor and the source of the second MOS transistor respectively. The drain of the first MOS transistor is grounded through the third resistor, and the gate of the first MOS transistor is connected to the first terminal of the differential input signal. The drain of the second MOS transistor is grounded through the fourth resistor, and the gate of the second MOS transistor is connected to the second terminal of the differential input signal.

8. The interface circuit as described in claim 7, characterized in that, The amplification unit further includes an impedance matching component, which is connected to the gate of the first MOS transistor and the gate of the second MOS transistor, respectively.

9. The interface circuit as described in any one of claims 1 to 3, characterized in that, The conversion module includes a third MOSFET, a fourth MOSFET, a fifth MOSFET, a sixth MOSFET, a seventh MOSFET, an eighth MOSFET, a ninth MOSFET, and a tenth MOSFET; The gate of the third MOS transistor is connected to the second terminal of the differential input signal and grounded through the fourth MOS transistor; the gate of the fifth MOS transistor is connected to the first terminal of the differential input signal and grounded through the sixth MOS transistor; the gate of the fourth MOS transistor is connected to the gate of the sixth MOS transistor. The drain of the fifth MOS transistor is connected to the gate of the seventh MOS transistor and the gate of the eighth MOS transistor, respectively. The drain of the seventh MOS transistor is grounded through the eighth MOS transistor and connected to the gate of the ninth MOS transistor and the gate of the tenth MOS transistor, respectively. The drain of the ninth MOS transistor is grounded through the tenth MOS transistor and outputs the digital signal.

10. An electronic device, characterized in that, Includes the interface circuit as described in any one of claims 1-9.

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