4g remote communication system for digital seismograph

Abstract

The utility model discloses a 4G remote communication system for digital seismograph, including power supply module and 4G module, power supply module is equipped with DC DC converter, DC DC converter converts external input voltage to be the working voltage of 4G module, a plurality of low ESR capacitors are provided between the input voltage end of 4G module and the ground in parallel, the utility model has the advantages of high stability and reliability, has the ability of offline self -recovery, strong anti -interference capability etc.

Description

Technical Field

[0001] This utility model relates to the field of 4G communication technology, specifically a 4G remote communication system for a digital seismograph. Background Technology

[0002] Existing digital seismographs primarily transmit data to host computers or data centers via serial ports or wired Ethernet. However, in scenarios such as field earthquake observation, unmanned mountain monitoring points, and geological disaster monitoring, wired networks are difficult to lay, have high maintenance costs, and poor real-time data performance, failing to meet the requirements for continuous, high-precision waveform data remote transmission. To achieve real-time data transmission from remote unmanned observation points, some systems currently use 4G wireless communication modules connected to a microcontroller system, but this presents the following problems: First, the peak current of the 4G module during transmission can reach 2A~3A; insufficient power supply filtering can cause system disconnection or reset. Second, network disconnection recovery is unstable, lacking hardware-level network monitoring and automatic restart mechanisms. Third, the communication circuit has weak anti-interference capabilities; the high-frequency ADC and 4G module share the same board wiring, making them susceptible to radio frequency interference, leading to data packet loss or serial port errors. Utility Model Content

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a 4G remote communication system for digital seismographs that is highly stable and reliable, has self-recovery capability after disconnection, and strong anti-interference capability.

[0004] The technical solution adopted by this utility model to solve its technical problem is: A 4G remote communication system for a digital seismograph, characterized in that: it includes a power supply module and a 4G module, the power supply module is equipped with a DC-DC converter, the DC-DC converter converts the external input voltage into the operating voltage of the 4G module, and a number of low ESR capacitors are connected in parallel between the input voltage terminal of the 4G module and ground. The external power supply is converted into the operating voltage of the 4G module by a DC-DC converter. The DC-DC converter and the low ESR capacitor work together to provide the 4G module with a power supply with fast transient response capability to cope with the instantaneous large current generated by the 4G module during transmission, and to prevent module communication drop or system reset problems caused by power supply voltage drop or excessive ripple.

[0005] The switching node of the DC-DC converter described in this utility model is connected to the input voltage terminal of the 4G module via inductor L3; the value of inductor L3 ranges from 0.1µH to 50µH; through the energy storage and freewheeling effect of the inductor, the ripple of the output current is smoothed, and at the same time, the inductor and the low ESR capacitor form a filter network to convert the pulse voltage of the switching node into a smooth DC voltage, thereby achieving stable power supply.

[0006] The low ESR capacitor of this invention includes capacitors C52, C53, and C57 connected in parallel; capacitor C52 has a capacitance of 10µF to 1mF, capacitor C53 has a capacitance of 0.5µF to 100µF, and capacitor C57 has a capacitance of 0.01µF to 1µF; by configuring multiple capacitance values, suppression of noise at different frequencies can be achieved. Capacitor C52 is used to suppress intermediate frequency ripple, capacitor C53 is used to suppress high frequency noise at the MHz level, and capacitor C57 is used to suppress radio frequency interference from tens of MHz to hundreds of MHz.

[0007] An electrolytic capacitor C50 is also provided between the input voltage terminal and ground of the 4G module of this invention. The electrolytic capacitor C50 is connected in parallel with a low ESR capacitor. The capacitance of the electrolytic capacitor C50 is 1µF~1mF. It is used to provide instantaneous large current when the 4G module is transmitting, to compensate for voltage drops, and to maintain the stability of the power supply voltage.

[0008] The present invention further includes a Zener diode D11 between the input voltage terminal of the 4G module and ground. The Zener diode D11 is connected in parallel with a low ESR capacitor. The Zener diode D11 is used to provide overvoltage clamping protection for the 4G module. When the input voltage exceeds its breakdown voltage, it limits the voltage across its terminals to a safe range.

[0009] The enable pin of the DC-DC converter described in this utility model is controlled by a transistor Q9. The base of the transistor Q9 is connected to the GPIO pin of the main control unit, the emitter is grounded, and the collector is connected to the enable pin. The main control unit outputs high and low level signals to control the power supply module to turn on and off.

[0010] The hardware reset pin of the 4G module described in this invention is controlled by a transistor Q7. The base of the transistor Q7 is connected to the GPIO pin of the main control unit, the emitter is grounded, and the collector is connected to the hardware reset pin. The main control unit outputs high and low level signals to trigger a hardware-level forced restart of the 4G module to restore network connectivity.

[0011] The network indicator pin of the 4G module described in this utility model is connected to the main control unit via transistor Q8. The base of transistor Q8 is connected to the network indicator pin, the emitter is grounded, the collector is connected to the status detection pin of the main control unit, and the collector is connected to the power supply through pull-up resistor R24. The input voltage terminal of the 4G module is connected to the network indicator pin of the 4G module via a series resistor R26 and a light-emitting diode LED1. The working status of the 4G module is displayed intuitively by LED indicator lights. At the same time, the 4G module provides status signals to the main control unit, enabling the main control unit to know the real-time status of the module and realize the dual functions of status indication and software monitoring.

[0012] The ground terminal of the low ESR capacitor described in this invention is connected in series with a ferrite bead to suppress radio frequency and high frequency noise.

[0013] The digital ground pin of the 4G module described in this invention is connected to the system ground plane on the circuit board using a single-point connection method. This is used to constrain the return path of the noise current generated by the 4G module, prevent it from polluting the entire system ground plane, and thus reduce the return current coupling of radio frequency and high frequency interference to other circuits.

[0014] The beneficial effects of this utility model are as follows: The external power supply is converted into the operating voltage of the 4G module via a DC-DC converter. The coordinated operation of the DC-DC converter and the low-ESR capacitor provides the 4G module with a power supply capable of fast transient response, thus coping with the instantaneous large current generated during transmission and preventing communication drop or system reset caused by power supply voltage drops or excessive ripple. The main control unit outputs high and low level signals to control the power supply module's on / off state. The main control unit also outputs high and low level signals to trigger a hardware-level forced restart of the 4G module to restore network connectivity. LED indicators visually display the 4G module's operating status, while the 4G module provides status signals to the main control unit, enabling the main control unit to know the module's real-time status and achieving dual functions of status indication and software monitoring. Attached Figure Description

[0015] Figure 1 This is a circuit diagram of the power supply module.

[0016] Figure 2 This is a schematic diagram of a 4G module circuit.

[0017] Figure 3 This is a schematic diagram of the level conversion circuit between the 4G module and the main control unit.

[0018] Figure 4 This is a schematic diagram of the main control unit circuit. Detailed Implementation

[0019] The present invention will now be described in conjunction with the accompanying drawings and embodiments.

[0020] As attached Figure 1 The diagram shows a power supply module circuit. The power supply module is equipped with a DC-DC converter, which converts the external input voltage into the operating voltage of the 4G module. Several low ESR capacitors are connected in parallel between the input voltage terminal of the 4G module and ground. The external power supply is converted into the operating voltage of the 4G module by a DC-DC converter. The DC-DC converter and the low ESR capacitor work together to provide the 4G module with a power supply with fast transient response capability to cope with the instantaneous large current generated by the 4G module during transmission, and to prevent module communication drop or system reset problems caused by power supply voltage drop or excessive ripple.

[0021] In this embodiment, the DC-DC converter used is a synchronous step-down DC-DC converter of model SCT2430STER, which is used to convert the external power supply (7.4V lithium battery or 12V DC power) into the working voltage (3.8V) of the 4G module. The model of the DC-DC converter and the external power supply and the working voltage of the 4G module are not limited to those in this embodiment and can be set according to actual usage needs.

[0022] The switching node (SW pin) of the DC-DC converter is connected to the input voltage terminal of the 4G module via inductor L3; the value of inductor L3 ranges from 0.1µH to 50µH; through the energy storage and freewheeling effect of the inductor, the ripple of the output current is smoothed, and at the same time, the inductor and the low ESR capacitor form a filter network to convert the pulse voltage of the switching node into a smooth DC voltage, thereby achieving stable power supply.

[0023] In this embodiment, the inductance value of inductor L3 is 10μH.

[0024] The low ESR capacitors include capacitors C52, C53, and C57 connected in parallel; capacitor C52 has a capacitance of 10µF to 1mF, capacitor C53 has a capacitance of 0.5µF to 100µF, and capacitor C57 has a capacitance of 0.01µF to 1µF; by configuring multiple capacitance values, suppression of noise at different frequencies can be achieved. Capacitor C52 is used to suppress intermediate frequency ripple, capacitor C53 is used to suppress high frequency noise at the MHz level, and capacitor C57 is used to suppress radio frequency interference from tens of MHz to hundreds of MHz.

[0025] In this embodiment, capacitor C52 is a solid-state capacitor. The positive terminal of C52 is connected to the input voltage terminal of the 4G module, and the negative terminal is connected to digital ground (DGND). The capacitance is 100µF. A ceramic capacitor can also be used as needed. Capacitor C53 is a ceramic capacitor with a capacitance of 4.7µF, and capacitor C57 is a ceramic capacitor with a capacitance of 0.1µF.

[0026] In this embodiment, capacitors C53 and C57 are made of X5R or X7R material.

[0027] An electrolytic capacitor C50 and a Zener diode D11 are also provided between the input voltage terminal of the 4G module and the digital ground (DGND). Electrolytic capacitors C50, C52, C53, C57, and Zener diode D11 are connected in parallel. The electrolytic capacitor C50 has a capacitance of 1µF to 1mF and is used to provide a large instantaneous current when the 4G module transmits, to compensate for voltage drops, and to maintain the stability of the power supply voltage. Zener diode D11 is used to provide overvoltage clamping protection for the 4G module. When the input voltage exceeds its breakdown voltage, it limits the voltage across its terminals to a safe range.

[0028] In this embodiment, the electrolytic capacitor C50 has a capacitance of 470µF. The positive terminal of C50 is connected to the input voltage terminal of the 4G module, and the negative terminal is connected to digital ground (DGND).

[0029] In this embodiment, the Zener diode D11 is model BZT52C4V7S. The negative terminal of the Zener diode D11 is connected to the input voltage terminal of the 4G module, and the positive terminal is connected to digital ground. When an abnormal high voltage occurs at the input terminal, D11 breaks down quickly, clamping the input voltage at its rated breakdown value, thereby protecting the subsequent 4G module from damage.

[0030] The ground wire of the low ESR capacitor is connected in series with a ferrite bead to suppress radio frequency and high frequency noise.

[0031] The enable pin (EN pin) of the DC-DC converter is controlled by transistor Q9. The base of transistor Q9 is connected to the GPIO pin of the main control unit, the emitter is grounded, and the collector is connected to the enable pin. The main control unit outputs high and low level signals to control the power supply module to turn on and off.

[0032] In this embodiment, transistor Q9 is an NPN transistor, model DTC043ZEBTL. When the main control unit outputs a high level, transistor Q9 is turned on, pulling the enable pin to a low level, thereby turning on the DC-DC converter. When the main control unit outputs a low level, transistor Q9 is turned off, the enable pin is pulled up to a high level, and the DC-DC converter is turned off.

[0033] The voltage input pin (VIN pin) of the DC-DC converter is connected to ground by resistors R27 and R28 arranged in series, and the connection point of resistors R27 and R28 is connected to the EN pin. In this embodiment, resistor R27 has a resistance of 510 kΩ and resistor R28 has a resistance of 120 kΩ; The VIN pin is also connected to ground by capacitors C54, C55 and C56 connected in parallel; capacitor C54 has a capacitance of 10µF-1mF, capacitor C55 has a capacitance of 0.1µF-50µF, and capacitor C56 has a capacitance of 1nF-1µF. In this embodiment, capacitor C54 is an electrolytic capacitor. The positive terminal of C54 is connected to the VIN pin, and the negative terminal is connected to digital ground. The capacitance is 470µF. The capacitance of capacitor C55 is 4.7µF, and the capacitance of capacitor C56 is 100nF. Resistors R27 and R28 are connected in series to form a voltage divider network, which provides undervoltage lockout for the DC-DC converter. When the input voltage is lower than a preset threshold, the converter is automatically shut down to protect the system. Electrolytic capacitor C54 is used as a low-frequency energy storage buffer to prevent the input voltage from dropping. Capacitor C55 is used to suppress intermediate frequency switching ripple, and capacitor C56 is used to suppress high-frequency noise. The parallel capacitors can work together to cope with the current demand and noise interference across the entire frequency range from low to high frequencies, providing a clean and stable input power supply for the DC-DC converter and the subsequent 4G module.

[0034] The frequency setting pin (RT / CLK pin) of the DC-DC converter is grounded via resistor R29; it is used to set the operating frequency of the chip.

[0035] In this embodiment, the resistor R29 has a resistance of 200 kΩ.

[0036] The BOOT pin of the DC-DC converter is electrically connected to the SW pin via capacitor C51. Capacitor C51 acts as a bootstrap capacitor, providing a floating power supply to the high-side gate drive circuit inside the chip, ensuring that the high-side power switch can be fully turned on, thereby improving power conversion efficiency. In this embodiment, capacitor C51 has a capacitance of 0.1µF.

[0037] The feedback pin (FB pin) of the DC-DC converter is connected to the junction of resistors R31 and R32. The end of resistor R31 away from the FB pin is grounded, and the end of resistor R32 away from the FB pin is connected to the input voltage terminal of the 4G module. Resistors R31 and R32 form a resistor voltage divider feedback network. By setting the resistance ratio of resistors R31 and R32, output voltage sampling and feedback are provided for the DC-DC converter, and the input voltage of the 4G module is accurately stabilized at a preset value.

[0038] In this embodiment, resistor R31 has a resistance of 10 kΩ and resistor R32 has a resistance of 39.2 kΩ.

[0039] The EP pin of the DC-DC converter is connected to digital ground (DGND) for chip heat dissipation and mechanical reinforcement.

[0040] The GND pin of the DC-DC converter is connected to digital ground; a capacitor C58 is connected between the GND pin and the frequency compensation pin (COMP pin) of the DC-DC converter. The end of the capacitor C58 closest to the COMP pin is connected to a resistor R30 and a capacitor C59 in sequence and then grounded; this is used to compensate the frequency characteristics of the feedback control loop of the DC-DC converter to ensure the stability and transient response performance of the power supply module when the load changes dynamically.

[0041] In this embodiment, capacitor C58 has a capacitance of 22 pF, capacitor C59 has a capacitance of 3.3 nF, and resistor R30 has a resistance of 33.2 kΩ.

[0042] In this embodiment, the power supply module has an input voltage range of 6V~12V, an output voltage of 3.8V, and a peak output current of 2A (applicable to 4G module transmission current fluctuations).

[0043] In this embodiment, the power supply module can stably output a voltage of 3.8V. Even if the instantaneous current of the 4G module transmission exceeds 2A, the system can remain stable and not reset, thus improving the overall reliability of the device.

[0044] As attached Figure 2 The diagram shows a 4G module circuit. Quectel EC20 MiniPCIe is selected, but Quectel SIM7600, Huawei ME909, etc. can also be selected as needed to perform remote data transmission functions.

[0045] The power input pin (VBAT pin) of the 4G module is connected to the input voltage terminal of the 4G module.

[0046] The output pin (VOUT pin) of the 4G module is connected to an external power supply module, and a capacitor C41 is connected between the VOUT pin and ground. The capacitor C41 is used to stabilize the voltage of the power output pin and filter out high-frequency noise, ensuring a stable and clean power supply for the peripheral circuits.

[0047] In this embodiment, capacitor C41 has a capacitance of 106 nF.

[0048] The 4G module's SIM card interface is connected to the SIM card slot, including: The SIM card power supply pin (USIM VDD pin) of the 4G module is connected to the VDD pin of the SIM card to supply power to the SIM card; The SIM card data communication pin (USIM DAT pin) of the 4G module is connected to the DATA pin of the SIM card for data transmission between the 4G module and the SIM card. The SIM card synchronization clock signal pin (USIM CLK pin) of the 4G module is connected to the CLK pin of the SIM card to provide a synchronization clock signal for SIM card communication; The SIM card reset signal pin (USIM RST pin) of the 4G module is connected to the RST pin of the SIM card and is used to reset the SIM card.

[0049] The hardware reset pin (PERST pin) of the 4G module is controlled by transistor Q7. The base of transistor Q7 is connected to the GPIO pin of the main control unit, the emitter is connected to digital ground, and the collector is connected to the hardware reset pin. The main control unit outputs high and low level signals to trigger a hardware-level forced restart of the 4G module to restore network connectivity.

[0050] In this embodiment, transistor Q7 is an NPN transistor, model DTC043ZEBTL. When the main control unit outputs a high level for more than 300ms, transistor Q7 is turned on, pulling the hardware reset pin to a low level and triggering the 4G module hardware reset. When the main control unit outputs a low level, transistor Q7 is turned off, the hardware reset pin is pulled up to a high level (invalid level), and the 4G module works normally.

[0051] The network indicator pin (LED WWAN pin) of the 4G module is connected to the main control unit via transistor Q8. The base of transistor Q8 is connected to the network indicator pin, the emitter is connected to digital ground, and the collector is connected to the status detection pin of the main control unit (the STATUS pin of the MCU). The collector is also connected to the power supply through a pull-up resistor R24. In this embodiment, transistor Q8 is an NPN transistor, model DTC043ZEBTL. The resistance of resistor R24 ​​is 100 kΩ. When the network indicator pin outputs a high level, transistor Q8 is turned on, pulling the STATUS pin of the MCU low. When the network indicator pin outputs a low level, transistor Q8 is turned off, pulling the STATUS pin of the MCU high. The main control unit can determine the working status of the 4G module by monitoring the high and low level changes of the STATUS pin.

[0052] The input voltage terminal (V4G) of the 4G module is connected to the network indicator pin of the 4G module via a series resistor R26 and a light-emitting diode LED1; in this embodiment, the resistance of resistor R26 is 2.2 kΩ, and the light-emitting diode LED1 is model SZYY0603R. The working status of the 4G module is displayed intuitively by LED indicator lights. At the same time, the 4G module provides status signals to the main control unit, enabling the main control unit to know the real-time status of the module and realize the dual functions of status indication and software monitoring.

[0053] In this embodiment, the 4G module has reserved USB data interfaces (USB DP, USB DN pins) for firmware upgrades or high-speed data channels.

[0054] The 4G module's universal asynchronous transceiver interface is connected to the corresponding interface of the main control unit, including: The UART RXD pin of the 4G module is connected to the MAIN TXD pin of the main control unit to receive data from the main control unit; The UART TXD pin of the 4G module is connected to the MAIN RXD pin of the main control unit to send data to the main control unit; The UART RTS pin of the 4G module is connected to the MAIN CTS pin of the main control unit to implement hardware flow control; The UART CTS pin of the 4G module is connected to the MAIN RTS pin of the main control unit to implement hardware flow control.

[0055] A level conversion chip is provided between the universal asynchronous transceiver interface of the 4G module and the corresponding interface of the main control unit; it is used to perform logic level conversion between different operating voltages of the 4G module and the main control unit to ensure the accuracy and reliability of communication signals.

[0056] The digital ground pin of the 4G module is connected to the system ground plane on the circuit board using a single-point connection method. This is used to constrain the return path of the high-frequency noise current generated by the 4G module, prevent it from polluting the entire system ground plane, and thus reduce the return current coupling of radio frequency and high-frequency interference to other circuits.

[0057] As attached Figure 3 As shown, in this embodiment, the voltage level conversion chip is a chip with the model number TXB0104PWR.

[0058] As attached Figure 4 As shown, in this embodiment, the main control unit uses an STM32F407VGT6 or STM32F407VET5 microcontroller as the core control chip, which is responsible for data acquisition, processing and communication management.

[0059] When using this utility model: 1. The main control MCU outputs a high level through the GPIO pin, which turns on the transistor Q9, pulls the enable pin (EN pin) of the DC-DC converter to a low level, and turns on the DC-DC converter; 2. The DC-DC converter converts the external input voltage (7.4V lithium battery or 12V DC power) into the operating voltage (3.8V) of the 4G module. Through the cooperation of several low ESR capacitors connected in parallel between the input voltage terminal of the 4G module and ground, the DC-DC converter provides the 4G module with a power supply with fast transient response capability to cope with the instantaneous large current generated by the 4G module during transmission, and prevents module communication disconnection or system reset problems caused by power supply voltage drop or excessive ripple. 3. When the 4G module is working, data is transmitted between the universal asynchronous transceiver interface of the 4G module and the corresponding interface of the main control MCU; and the logic level is converted between the universal asynchronous transceiver interface of the 4G module and the corresponding interface of the main control MCU through a level conversion chip to ensure the accuracy and reliability of the communication signal. 4. LED1 visually displays the operating status of the 4G module, and the status of the 4G module is fed back to the main control MCU via transistor Q8. When the network indicator pin of the 4G module outputs a high level, transistor Q8 is turned on, pulling the STATUS pin of the MCU low. When the network indicator pin outputs a low level, transistor Q8 is turned off, pulling the STATUS pin of the MCU high. The main control unit can determine the operating status of the 4G module by monitoring the high and low level changes of the STATUS pin. 5. When a forced restart of the 4G module is required, the main control MCU outputs a high level, the transistor Q7 is turned on, and the hardware reset pin is pulled to a low level, triggering the hardware reset of the 4G module and realizing the forced restart of the 4G module.

Claims

1. A 4G remote communication system for a digital seismograph, characterized in that: It includes a power supply module and a 4G module. The power supply module is equipped with a DC-DC converter, which converts the external input voltage into the operating voltage of the 4G module. Several low ESR capacitors are connected in parallel between the input voltage terminal of the 4G module and ground.

2. The 4G remote communication system for a digital seismograph according to claim 1, characterized in that: The switching node of the DC-DC converter is connected to the input voltage terminal of the 4G module via inductor L3; the value of inductor L3 ranges from 0.1µH to 50µH.

3. A 4G remote communication system for a digital seismograph according to claim 1 or 2, characterized in that: The low ESR capacitors include capacitors C52, C53, and C57 connected in parallel; capacitor C52 has a capacitance of 10µF to 1mF, capacitor C53 has a capacitance of 0.5µF to 100µF, and capacitor C57 has a capacitance of 0.01µF to 1µF.

4. The 4G remote communication system for a digital seismograph according to claim 3, characterized in that: An electrolytic capacitor C50 is also provided between the input voltage terminal of the 4G module and ground. The electrolytic capacitor C50 is connected in parallel with a low ESR capacitor. The capacitance of the electrolytic capacitor C50 is 1µF~1mF.

5. A 4G remote communication system for a digital seismograph according to claim 3, characterized in that: A Zener diode D11 is also provided between the input voltage terminal of the 4G module and ground, and the Zener diode D11 is connected in parallel with a low ESR capacitor.

6. A 4G remote communication system for a digital seismograph according to claim 1, 2, 4, or 5, characterized in that: The enable pin of the DC-DC converter is controlled by transistor Q9. The base of transistor Q9 is connected to the GPIO pin of the main control unit, the emitter is grounded, and the collector is connected to the enable pin.

7. A 4G remote communication system for a digital seismograph according to claim 1, 2, 4, or 5, characterized in that: The hardware reset pin of the 4G module is controlled by transistor Q7. The base of transistor Q7 is connected to the GPIO pin of the main control unit, the emitter is grounded, and the collector is connected to the hardware reset pin. The main control unit outputs high and low level signals to trigger a hardware-level forced restart of the 4G module to restore network connectivity.

8. A 4G remote communication system for a digital seismograph according to claim 1, 2, 4, or 5, characterized in that: The network indicator pin of the 4G module is connected to the main control unit via transistor Q8. The base of transistor Q8 is connected to the network indicator pin, the emitter is grounded, the collector is connected to the status detection pin of the main control unit, and the collector is connected to the power supply through pull-up resistor R24. The input voltage terminal of the 4G module is connected to the network indicator pin of the 4G module via a series resistor R26 and a light-emitting diode LED1.

9. A 4G remote communication system for a digital seismograph according to claim 1, 2, 4, or 5, characterized in that: A ferrite bead is connected in series with the ground terminal of the low ESR capacitor.

10. A 4G remote communication system for a digital seismograph according to claim 1, 2, 4, or 5, characterized in that: The digital ground pin of the 4G module is connected to the system ground plane on the circuit board using a single-point connection method.

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