Data acquisition system based on LVDS (Low Voltage Differential Signaling) controller

Abstract

The utility model discloses a controller data acquisition system based on LVDS (Low Voltage Differential Signaling), which comprises a controller, a data conversion unit and a data processing unit, the data conversion unit comprises a first conversion unit, an Ethernet cable, a second conversion unit and a third conversion unit, SPI (Serial Peripheral Interface) signals generated by the controller are converted into LVDS signals through the first conversion unit to be transmitted, and the LVDS signals are transmitted through the data processing unit. The LVDS signals are transmitted to the second conversion unit through the Ethernet cable, the second conversion unit converts the LVDS signals into SPI signals and then transmits the SPI signals to the third conversion unit, and the third conversion unit analyzes the SPI signals into data and transmits the data to the data processing unit for data processing. According to the utility model, the defects in the existing long-distance signal transmission based on the SPI protocol can be obviously improved, the SPI signal is converted into the LVDS signal for transmission, the differential signal characteristic of the LVDS is utilized, the external electromagnetic interference is effectively inhibited, the anti-noise capability is stronger, the time sequence error is reduced, and the precision of the whole data acquisition system is improved.

Description

Technical Field

[0001] This utility model relates to the field of data transmission technology, and in particular to a data acquisition system based on an LVDS (Low-Voltage Differential Signaling) controller. Background Technology

[0002] In automotive electronic products, various types of signal data often serve as information references for product design, testing, verification, correction, and validation. Currently, the widely used signal transmission method is based on the SPI (Serial Peripheral Interface) protocol. To transmit controller data to a computer for acquisition and analysis, this method typically transmits signals directly to the computer via the controller's clock and data cabling. While the SPI protocol provides stable transmission performance in short-distance and low-noise environments, over long distances, as the cabling length increases, asynchrony between the clock and data signals may occur, leading to errors during data parsing and data loss. Furthermore, excessively long cabling is susceptible to external electromagnetic interference during transmission, causing data distortion and rendering the data unusable. Therefore, existing long-distance signal transmission technologies based on the SPI protocol struggle to meet the requirements for data integrity and interference resistance under complex operating conditions. Utility Model Content

[0003] The purpose of this invention is to solve the problem that current technologies cannot stably acquire, transmit, and receive signals over long distances and under multiple operating conditions. This invention provides a data acquisition system based on an LVDS controller, which can make long-distance signal data more complete, make high and low temperature signal transmission more stable, reduce signal disturbances, and reduce the risk of data errors.

[0004] To address the aforementioned technical problems, this utility model discloses an LVDS-based controller data acquisition system, comprising a controller, a data conversion unit, and a data processing unit. The data conversion unit includes a first conversion unit, an Ethernet cable, a second conversion unit, and a third conversion unit. The SPI signal generated by the controller is converted into an LVDS signal by the first conversion unit for transmission. The LVDS signal is transmitted to the second conversion unit via the Ethernet cable. The second conversion unit converts the LVDS signal back into an SPI signal and transmits it to the third conversion unit. The third conversion unit parses the SPI signal into data and transmits it to the data processing unit for data processing.

[0005] The above technical solution can significantly improve the shortcomings of existing long-distance signal transmission based on the SPI protocol. By converting the SPI signal into an LVDS signal for transmission, the differential signal characteristics of LVDS can be utilized to effectively suppress external electromagnetic interference and have strong anti-noise capabilities. At the same time, since the differential signal switching depends on the intersection of the two signal lines, the sensitivity to timing drift is reduced, and timing errors caused by interference such as temperature changes are avoided, thereby improving the accuracy of the entire data acquisition system.

[0006] Optionally, the first conversion unit includes:

[0007] An LVDS differential driver is used to convert SPI signals into LVDS signals and transmit them to an Ethernet cable;

[0008] A voltage conversion circuit is used to convert the voltage level of an external power supply to a voltage level suitable for an LVDS differential driver;

[0009] Protection circuitry is used to protect the voltage conversion circuitry and the LVDS differential driver.

[0010] Optionally, the voltage conversion circuit includes:

[0011] The power adapter module is used to receive external power and provide voltage to the protection circuit. The power adapter module includes a first filter capacitor, a first linear regulator and a second linear regulator. The first linear regulator is used to output a 5V voltage and the second linear regulator is used to output a 3.3V voltage.

[0012] A targeted power supply module is used to provide voltage to the LVDS differential driver. The targeted power supply module includes a second filter capacitor and a third linear regulator, which is used to output a 3.3V voltage.

[0013] Optionally, the protection circuit includes a first series resistor, an electrostatic discharge and surge protection device, a Schmitt trigger, and a digital isolator. The output of the electrostatic discharge and surge protection device is connected to the input of the Schmitt trigger. The SPI signal generated by the controller is transmitted to the Schmitt trigger through the first series resistor, and then the Schmitt trigger transmits the SPI signal to the digital isolator. After passing through the digital isolator, the signal is transmitted to the LVDS differential driver.

[0014] Optional, electrostatic discharge and surge protection devices include an array of low-capacitance transient voltage suppression diodes.

[0015] Optionally, the Ethernet cable is routed using an S / FTP shielded cable, which includes a double shield and is grounded using a shielded RJ45 connector. The shielded RJ45 connector is used to provide shielding for the Ethernet cable.

[0016] Optionally, the second conversion unit includes:

[0017] The LVDS receiver is used to receive LVDS signals transmitted via Ethernet cable and convert them into SPI signals. The output of the LVDS receiver is connected to the third conversion unit through a second series resistor.

[0018] A power management circuit, the output of which is connected to the input of the LVDS receiver, includes:

[0019] The fourth linear regulator is used to provide 3.3V to the LVDS receiver;

[0020] The filter circuit, including an inductor and a thermistor, is connected to the input of the fourth linear regulator.

[0021] An electrostatic discharge protection device is provided, with its input terminal connected to the output terminal of the fourth linear voltage regulator.

[0022] Optionally, the electrostatic discharge protection device includes an array of ultra-low capacitance transient voltage suppression diodes. Attached Figure Description

[0023] Figure 1 This diagram illustrates the overall structural principle of the LVDS controller-based data acquisition system in an embodiment of this utility model.

[0024] Figure 2 This diagram illustrates the structural principle of the first conversion unit in an embodiment of the present invention.

[0025] Figure 3 The diagram shows the structural principle of the second conversion unit in an embodiment of this utility model. Detailed Implementation

[0026] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. Although the description of this utility model will be presented in conjunction with preferred embodiments, this does not mean that the features of this utility model are limited to this embodiment. On the contrary, the purpose of describing the utility model in conjunction with the embodiments is to cover other options or modifications that may be derived based on the claims of this utility model. To provide a deep understanding of this utility model, many specific details will be included in the following description. This utility model may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of this utility model, some specific details will be omitted in the description. It should be noted that, without conflict, the embodiments and features in the embodiments of this utility model can be combined with each other.

[0027] It should be noted that in this specification, similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0028] The terms “first”, “second”, etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0029] In the description of this embodiment, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment based on the specific circumstances.

[0030] To make the objectives, technical solutions, and advantages of this utility model clearer, the embodiments of this utility model will be described in further detail below with reference to the accompanying drawings.

[0031] To address the challenge that the SPI protocol struggles to meet the requirements for data integrity and anti-interference performance in long-distance and multi-condition signal acquisition, transmission, and reception tasks, this utility model application discloses a data acquisition system based on an LVDS controller. LVDS, due to its inherent characteristics, possesses strong noise immunity, effectively suppressing electromagnetic interference and reducing timing errors. This results in more complete long-distance signal data, more stable high and low temperature signal transmission, reduced signal disturbances, and a decreased risk of data errors.

[0032] like Figure 1 As shown, the data acquisition system includes a controller, a data conversion unit, and a data processing unit. The data conversion unit includes a first conversion unit, an Ethernet cable, a second conversion unit, and a third conversion unit.

[0033] The controller generates SPI-based data signals, including clock, enable, and data signals. These signals are transmitted to the first conversion unit for data conversion via corresponding interfaces. In the first conversion unit, the SPI signal output by the controller is stabilized and converted into an LVDS signal, which is then transmitted to the Ethernet cable for data transmission. To enhance signal anti-interference capabilities, the Ethernet cable uses shielded twisted-pair cable and a shielded RJ45 connector, ensuring that the signal is not affected by external interference during long-distance transmission. The second conversion unit receives the LVDS signal transmitted via the Ethernet cable, restores the LVDS signal to an SPI signal, and transmits the SPI signal to the third conversion unit via an interface. The third conversion unit is responsible for parsing the SPI signal output by the second conversion unit into data and transmitting the converted data to the data processing unit for further processing.

[0034] The above technical solution can significantly improve the shortcomings of existing long-distance signal transmission based on the SPI protocol. By converting the SPI signal into an LVDS signal for transmission, the differential signal characteristics of LVDS can be utilized to effectively suppress external electromagnetic interference and have strong anti-noise capabilities. At the same time, since the switching change of the differential signal is located at the intersection of the two signals, unlike ordinary single-ended signals which rely on two threshold voltages, it is less affected by process and temperature, effectively reducing timing errors and facilitating effective signal transmission, thereby improving the accuracy of the entire data acquisition system.

[0035] The following, combined with Figure 2 The first conversion unit will be described in detail.

[0036] According to an embodiment of this application, the first conversion unit includes an LVDS differential driver, a voltage conversion circuit, and a protection circuit. The LVDS differential driver converts the SPI signal into an LVDS signal and transmits it via an Ethernet cable. The voltage conversion circuit converts the voltage and provides voltage to the protection circuit and the LVDS differential driver. The protection circuit is primarily responsible for protecting the voltage conversion circuit and the LVDS differential driver from electromagnetic interference and other potential destructive factors.

[0037] like Figure 2 As shown, the voltage conversion circuit includes a power adapter module and a targeted power supply module, and the protection circuit includes a first series resistor, an electrostatic discharge and surge protection device, a Schmitt trigger, and a digital isolator.

[0038] The power adapter module may include diodes, a first filter capacitor, a first linear regulator, and a second linear regulator (not shown in the figure). In this embodiment, all linear regulators can be the MCP1792T high-voltage, low-dropout linear regulator from Microchip Technology Corporation. Those skilled in the art will understand that the specific models described above are further detailed descriptions of this invention in conjunction with specific embodiments, and should not be construed as limiting the specific implementation of this invention to these models. Other models of the same device do not deviate from the spirit and scope of this invention. The first linear regulator reduces the 12V external input power supply to 5V, providing a fixed 5V operating voltage for the second linear regulator and the electrostatic surge protection device. The second linear regulator reduces the 5V input voltage to 3.3V, providing a fixed 3.3V operating voltage for the protection circuit. Simultaneously, the combination of diodes and capacitors in the power adapter module achieves transient protection of the power supply voltage, preventing damage to circuit components from instantaneous high voltage or voltage spikes. The targeted power supply module may include a second filter capacitor and a third linear regulator. The third linear regulator, in combination with a capacitor and an inductor, reduces the 12V voltage to 3.3V to provide a fixed 3.3V operating voltage for the LVDS differential driver.

[0039] After the SPI signal generated by the controller enters the first conversion unit through the interface, it first passes through the first series resistor to absorb interference pulses, and then is transmitted to the Schmitt trigger for buffering and shaping. In this embodiment, the Schmitt trigger uses the 74LV14 low-voltage logic chip from the 74LVxx series and operates at 3.3V. The 74LV14 is a hex inverting Schmitt trigger that can convert slow-edge analog signals into clear digital square wave signals, ensuring that the input SPI signal has clear waveform edges and good anti-interference performance. After passing through the Schmitt trigger, the SPI signal is transmitted to the digital isolator. In this embodiment, the digital isolator uses the ISO7730FQ from the ISO773x series of Texas Instruments and operates at 3.3V. This device has an isolation voltage of 5000VRMS, which can protect the entire circuit from high voltage and lightning strikes. At the same time, the ISO7730FQ also has excellent electromagnetic compatibility and is designed to provide enhanced insulation. In addition, to protect the first linear regulator of the 5V power supply device, an electrostatic discharge (ESD) and surge protection device needs to be connected in parallel with the first series resistor. This protection device may include a resistor and a diode array. In this embodiment, a low-capacitance transient voltage suppressor diode array SRV05-4 from ON Semiconductor and Sentex is used to ensure signal integrity during high-speed data communication, while providing strong overvoltage protection, which can quickly limit the voltage to a safe range in the event of overvoltage. Those skilled in the art will understand that the above specific models are a further detailed description of this utility model in conjunction with specific embodiments, and should not be construed as limiting the specific implementation of this utility model to only this model. Other models of the same device do not depart from the spirit and scope of this utility model.

[0040] The SPI signal is transmitted to the LVDS differential driver for conversion after passing through a digital isolator. In this embodiment, the SN65LVDS31M four-channel high-speed differential driver from Texas Instruments (TI) operates at 3.3V. This differential driver features high data transmission speed and low power consumption, converting the SPI input signal into an LVDS signal suitable for long-distance transmission. The LVDS signal is then output from the LVDS differential driver to an Ethernet cable for data transmission. Those skilled in the art will understand that the specific model described above is a further detailed description of this invention in conjunction with specific embodiments, and should not be construed as limiting the specific implementation of this invention to this model. Other models of devices do not depart from the spirit and scope of this invention.

[0041] The following, combined with Figure 3 The second conversion unit will be described in detail.

[0042] According to an embodiment of this application, the second conversion unit includes an LVDS receiver and a power management circuit. The LVDS receiver is used to receive LVDS signals transmitted via an Ethernet cable and convert them back to SPI signals. The power management circuit is used to convert voltage and provide voltage to the LVDS receiver.

[0043] like Figure 3 As shown, the power management circuit includes a fourth linear regulator, a filter circuit, and an electrostatic discharge protection device.

[0044] The filtering circuit includes an inductor and a thermistor. The inductor filters noise, ensures stable power supply, and prevents high-frequency noise and electromagnetic interference. The thermistor protects the circuit. The filtering circuit is connected to the input of the fourth linear regulator, which reduces the 5V input voltage to 3.3V to provide a fixed 3.3V operating voltage for the LVDS receiver. Simultaneously, to protect the 3.3V power supply device, the fourth linear regulator, an electrostatic discharge (ESD) protection device is required in parallel with the LVDS receiver. This protection device may include a diode array. In this embodiment, an ultra-low capacitance transient voltage suppression diode, ESD5304, is used to provide ESD protection. Those skilled in the art will understand that the above specific models are further detailed descriptions of this invention in conjunction with specific embodiments, and should not be construed as limiting the specific implementation of this invention to these models. Other models of devices do not deviate from the spirit and scope of this invention.

[0045] The LVDS signal from the first conversion unit is transmitted to the second conversion unit via an Ethernet cable, where it is received and converted by the LVDS receiver. In this embodiment, a four-channel high-speed differential receiver SN65LVDT348 from Texas Instruments is used, operating at 3.3V. This receiver has strong anti-interference capabilities and can convert the LVDS input signal into a data signal based on the SPI protocol, including clock, enable, and data signals, ensuring signal integrity after long-distance transmission. The SPI signal is output from the LVDS receiver and, after passing through a second series resistor to absorb interference pulses, is transmitted to the third conversion unit via an interface. Those skilled in the art will understand that the above specific models are a further detailed description of this invention in conjunction with specific embodiments, and should not be construed as limiting the specific implementation of this invention to these models; other models of devices do not depart from the spirit and scope of this invention.

[0046] Furthermore, the third conversion unit integrates the receiving and transmission functions of the analog-to-digital converter, and is responsible for parsing the SPI signal output by the second conversion unit into data and transmitting the converted data to the data processing unit for further processing.

[0047] This invention uses LVDS technology to convert SPI signals into LVDS signals and transmit data over an Ethernet cable, thus overcoming the shortcomings of SPI-based protocols in long-distance transmission. By utilizing the characteristics of LVDS differential signals, it effectively suppresses external electromagnetic interference, reduces timing errors, and improves the anti-interference capability and transmission accuracy of the data acquisition system.

[0048] Although the present invention has been illustrated and described with reference to certain preferred embodiments, those skilled in the art should understand that the above description is a further detailed explanation of the present invention in conjunction with specific embodiments, and should not be construed as limiting the specific implementation of the present invention to these descriptions. Those skilled in the art can make various changes in form and detail, including some simple deductions or substitutions, without departing from the spirit and scope of the present invention.

Claims

1. A controller data acquisition system based on LVDS, characterized in that, The system includes a controller, a data conversion unit, and a data processing unit. The data conversion unit includes a first conversion unit, an Ethernet cable, a second conversion unit, and a third conversion unit. The SPI signal generated by the controller is converted into an LVDS signal by the first conversion unit for transmission. The LVDS signal is transmitted to the second conversion unit via the Ethernet cable. The second conversion unit converts the LVDS signal back into the SPI signal and transmits it to the third conversion unit. The third conversion unit parses the SPI signal into data and transmits it to the data processing unit for data processing.

2. The data acquisition system as described in claim 1, characterized in that, The first conversion unit includes: An LVDS differential driver is used to convert the SPI signal into an LVDS signal and transmit it to the Ethernet cable; A voltage conversion circuit is used to convert the voltage level of an externally supplied power source into a voltage level suitable for the LVDS differential driver; A protection circuit is provided to protect the voltage conversion circuit and the LVDS differential driver.

3. The data acquisition system as described in claim 2, characterized in that, The voltage conversion circuit includes: A power adapter module is used to receive external power and provide voltage to the protection circuit. The power adapter module includes a first filter capacitor, a first linear regulator and a second linear regulator. The first linear regulator is used to output a 5V voltage and the second linear regulator is used to output a 3.3V voltage. A targeted power supply module is provided to supply voltage to the LVDS differential driver. The targeted power supply module includes a second filter capacitor and a third linear regulator, which is used to output a 3.3V voltage.

4. The data acquisition system as described in claim 2 or 3, characterized in that, The protection circuit includes a first series resistor, an electrostatic discharge (ESD) and surge protection device, a Schmitt trigger, and a digital isolator. The output terminal of the ESD and surge protection device is connected to the input terminal of the Schmitt trigger. The SPI signal generated by the controller is transmitted to the Schmitt trigger through the first series resistor, and then the Schmitt trigger transmits the SPI signal to the digital isolator. After passing through the digital isolator, the signal is transmitted to the LVDS differential driver.

5. The data acquisition system as described in claim 4, characterized in that, The electrostatic discharge and surge protection device includes a low-capacitance transient voltage suppression diode array.

6. The data acquisition system as described in claim 5, characterized in that, The Ethernet cable is routed using an S / FTP shielded cable, which includes a double shielding layer. The S / FTP shielded cable is grounded using a shielded RJ45 connector, which provides shielding for the Ethernet cable.

7. The data acquisition system as described in claim 6, characterized in that, The second conversion unit includes: An LVDS receiver is used to receive the LVDS signal transmitted through the Ethernet cable and convert it into the SPI signal. The output terminal of the LVDS receiver is connected to the third conversion unit through a second series resistor. A power management circuit, the output of which is connected to the input of the LVDS receiver, the power management circuit comprising: A fourth linear regulator is used to provide a 3.3V voltage to the LVDS receiver; A filtering circuit, including an inductor and a thermistor, is connected to the input of the fourth linear regulator. An electrostatic discharge protection device is provided, wherein the input terminal of the electrostatic discharge protection device is connected to the output terminal of the fourth linear regulator.

8. The data acquisition system as described in claim 7, characterized in that, The electrostatic discharge protection device includes an array of ultra-low capacitance transient voltage suppression diodes.

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