A wireless internet of things terminal device

Abstract

The application provides a wireless Internet of Things terminal device, and belongs to the technical field of wireless Internet of Things terminals. The wireless Internet of Things terminal device comprises a shell and a circuit board arranged in the inner cavity of the shell, and the circuit board is integrated with a microprocessor, a wireless communication module electrically connected with the microprocessor, an embedded planar inverted F antenna connected on the wireless communication module, a sensor interface electrically connected with the microprocessor and used for connecting an external sensor, and a power management circuit electrically connected with the microprocessor and the sensor interface and used for supplying power to the microprocessor and the wireless communication module and selectively disconnecting the power supply circuit of the sensor interface. The embedded planar inverted F antenna and the power management circuit are respectively located on the opposite sides of the microprocessor, and the sensor interface is located on the side of the power management circuit away from the microprocessor. The application can reduce the interference on the antenna radiation performance, improve the communication quality and communication reliability of the wireless Internet of Things terminal device, and prolong the endurance time.

Description

Technical Field

[0001] This application relates to the field of wireless Internet of Things (IoT) terminal technology, and in particular to a wireless IoT terminal device. Background Technology

[0002] With the rapid development of IoT technology, wireless IoT terminal devices, as key equipment for achieving deep integration of the physical world and information networks, have been widely applied in many fields such as industrial monitoring, smart homes, environmental monitoring, and smart agriculture. These devices typically use a microprocessor as their core, responsible for data acquisition, logic operations, and communication control, and utilize low-power wireless communication modules to achieve remote data interaction with the cloud or other nodes. To meet the requirements of portable deployment and long-term stable operation, these devices generally employ highly integrated circuit designs, compactly arranging core functional units such as sensor interfaces and power management on the same circuit board, aiming to reduce size, lower overall power consumption, and improve reliability. Modern wireless IoT terminals are continuously evolving towards miniaturization, low power consumption, and high reliability to adapt to complex and diverse application scenarios.

[0003] In related technologies, wireless IoT terminal devices include a housing and a circuit board disposed in the inner cavity of the housing. The wireless communication module, radio frequency antenna and high-frequency digital circuit, analog power supply circuit and sensor interface are compactly arranged on the circuit board.

[0004] However, when the radiator of the RF antenna is too close to interference sources such as high-frequency digital circuits and analog power supply circuits, power supply noise can severely degrade antenna performance through near-field coupling. At the same time, frequent plugging and unplugging of sensor interfaces or long cable connections may introduce static electricity or noise, causing electromagnetic interference, which will further reduce antenna radiation efficiency and degrade communication quality, thus restricting the communication reliability of wireless IoT terminal devices in complex electromagnetic environments. Utility Model Content

[0005] This application provides a wireless IoT terminal device that can reduce interference with antenna radiation performance, improve communication quality and reliability, and extend battery life. The technical solution includes at least the following: On one hand, a wireless Internet of Things (IoT) terminal device is provided, including a housing and a circuit board disposed in the inner cavity of the housing. The circuit board integrates: a microprocessor; a wireless communication module electrically connected to the microprocessor, wherein an embedded planar inverted-F antenna is connected to the wireless communication module; a sensor interface electrically connected to the microprocessor for connecting an external sensor; and a power management circuit electrically connected to the microprocessor and the sensor interface for supplying power to the microprocessor and the wireless communication module and selectively disconnecting the power supply circuit of the sensor interface. The embedded planar inverted-F antenna and the power management circuit are located on opposite sides of the microprocessor, and the sensor interface is located on the side of the power management circuit furthest from the microprocessor.

[0006] Optionally, the circuit board is a rectangular circuit board, and the embedded planar inverted-F antenna and the power management circuit are respectively arranged on opposite sides of the microprocessor along the diagonal direction of the circuit board.

[0007] Optionally, the minimum distance between the embedded planar inverted-F antenna and the power management circuit is greater than or equal to 5 mm and less than or equal to 70 mm.

[0008] Optionally, the feed point of the radiator of the embedded planar inverted-F antenna is connected to the wireless communication module through a π-type impedance matching circuit.

[0009] Optionally, the power management circuit includes a buck regulator unit, a dynamic power consumption adjustment unit, and a battery protection unit connected in sequence.

[0010] Optionally, the dynamic power consumption adjustment unit includes a MOSFET switch array and a reference voltage source, wherein the MOSFET switch array is used to selectively disconnect the power supply circuit of the sensor interface.

[0011] Optionally, the MOS transistor switch array includes multiple P-channel MOS transistors arranged in parallel, each P-channel MOS transistor corresponding to a power supply circuit of the sensor interface, and the gate of the P-channel MOS transistor is connected to the microprocessor.

[0012] Optionally, the material of the housing is galvanized cold-rolled steel sheet.

[0013] Optionally, a signal pass-through window is provided on the housing at a corresponding position in the area where the embedded planar inverted-F antenna is located. The signal pass-through window is used to suppress the attenuation of the antenna signal.

[0014] Optionally, the material of the signal transmission window is polytetrafluoroethylene.

[0015] The beneficial effects of the technical solution provided in this application include at least the following: In this embodiment, by placing the embedded planar inverted-F antenna and the power management circuit on opposite sides of the microprocessor, with the sensor interface located on the side of the power management circuit furthest from the microprocessor, the layout of the embedded planar inverted-F antenna is optimized. This allows for a larger distance between the planar inverted-F antenna, the power management circuit, and the sensor interface, effectively reducing the interference of noise from the power management circuit and the sensor interface on the antenna radiation performance and improving the communication quality and reliability of the wireless IoT terminal device. Furthermore, the power management circuit not only supplies power to the microprocessor and the wireless communication module but can also selectively disconnect the power supply circuit to the sensor interface. When the external sensor connected to the sensor interface is idle, disconnecting its power supply circuit effectively reduces power consumption, thus improving the battery life of the wireless IoT terminal device. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying 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 three-dimensional structural diagram of a wireless Internet of Things terminal device provided in an embodiment of this application; Figure 2 This is a cross-sectional structural diagram of a wireless Internet of Things terminal device provided in an embodiment of this application; Figure 3 This is a schematic diagram of a cross-sectional structure of a circuit board provided in an embodiment of this application; Figure 4 This is a schematic diagram of a power management circuit provided in an embodiment of this application.

[0018] Figure label: 1: Housing; 2: Circuit board; 3: Microprocessor; 4: Wireless communication module; 5: Embedded planar inverted-F antenna; 6: Sensor interface; 7: Power management circuit; 8: Signal pass-through window; 9: Buck regulator unit; 10: Dynamic power consumption adjustment unit; 11: Battery protection unit; 12: MOSFET switch array; 13: Reference voltage source. Detailed Implementation

[0019] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms “first,” “second,” “third,” and similar terms used in this patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an” or “a” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “comprising” or “including” and similar terms mean that the element or object preceding “comprising” or “including” encompasses the element or object listed following “comprising” or “including” and its equivalents, and do not exclude other elements or objects. The terms “connected” or “linked” and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. “Up,” “down,” “left,” “right,” etc., are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described object changes. A and / or B indicates the presence of three cases: A, B, and A and B.

[0020] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0021] Figure 1 This is a three-dimensional structural diagram of a wireless Internet of Things terminal device provided in an embodiment of this application. Figure 2 This is a cross-sectional structural diagram of a wireless Internet of Things (IoT) terminal device provided in an embodiment of this application. See also... Figure 1 and Figure 2 The wireless IoT terminal device includes a housing 1 and a circuit board 2 disposed within the cavity of the housing 1. The circuit board 2 integrates: a microprocessor 3; a wireless communication module 4 electrically connected to the microprocessor 3, the wireless communication module 4 having an embedded planar inverted-F antenna 5 connected thereto; a sensor interface 6 electrically connected to the microprocessor 3 for connecting external sensors; and a power management circuit 7 electrically connected to the microprocessor 3 and the sensor interface 6, for supplying power to the microprocessor 3 and the wireless communication module 4 and selectively disconnecting the power supply circuit to the sensor interface 6. The embedded planar inverted-F antenna 5 and the power management circuit 7 are located on opposite sides of the microprocessor 3, and the sensor interface 6 is located on the side of the power management circuit 7 furthest from the microprocessor 3.

[0022] In this embodiment, by placing the embedded planar inverted-F antenna 5 and the power management circuit 7 on opposite sides of the microprocessor 3, and with the sensor interface 6 located on the side of the power management circuit 7 furthest from the microprocessor 3, the layout of the embedded planar inverted-F antenna 5 is optimized. This allows for a larger distance between the planar inverted-F antenna and the power management circuit 7 and sensor interface 6, effectively reducing the interference of noise from the power management circuit 7 and sensor interface 6 on the antenna radiation performance and improving the communication quality and reliability of the wireless IoT terminal device. Furthermore, the power management circuit 7 not only supplies power to the microprocessor 3 and the wireless communication module 4, but can also selectively disconnect the power supply circuit of the sensor interface 6. When the external sensor connected to the sensor interface 6 is idle, disconnecting its power supply circuit can effectively reduce power consumption, which is beneficial for improving the battery life of the wireless IoT terminal device.

[0023] Optionally, the material of the housing 1 can be an electromagnetic shielding material. For example, the material of the housing 1 is galvanized cold-rolled steel sheet. In this embodiment, the housing 1 can be made of 1.2mm thick cold-rolled steel sheet as the base material, with a galvanized passivation treatment on the surface to form a protective layer with a thickness of 5μm to 8μm. In this way, the housing 1 not only possesses an electromagnetic shielding effectiveness of greater than or equal to 30dB, effectively blocking external electromagnetic interference signals from entering the device, but also resists dust and moisture corrosion in the industrial environment, thereby extending the service life of the device.

[0024] For example, the housing 1 can be a cuboid structure of 80mm×50mm×15mm, which can meet the requirements of portable deployment and provide sufficient installation space for internal components. The corners of the cuboid structure housing 1 are rounded with a radius of 3mm to avoid bumps and damage caused by sharp edges.

[0025] For example, the side wall of the housing 1 may also be provided with two standard USB ports and one antenna debugging hole to facilitate the connection of external devices and subsequent maintenance.

[0026] Optionally, a signal transmission window 8 is provided on the housing 1 at a corresponding position in the area where the embedded planar inverted-F antenna 5 is located. The signal transmission window 8 is used to suppress the attenuation of the antenna signal. This can effectively reduce the obstruction of the antenna signal by the material of the housing 1, suppress the attenuation of the antenna signal, and ensure that the embedded planar inverted-F antenna 5 still has excellent wireless communication performance in the enclosed housing 1.

[0027] Optionally, the material of the signal transmission window 8 can be a non-metallic wave-transmitting material. For example, the material of the signal transmission window 8 is polytetrafluoroethylene (PTFE). PTFE has a dielectric constant of 2.1, a dielectric loss tangent of less than or equal to 0.0002, and a transmittance of greater than or equal to 98% in the 868MHz to 915MHz frequency band, ensuring that the embedded planar inverted-F antenna 5 still possesses excellent wireless communication performance within the enclosed housing 1. For instance, a 2mm thick PTFE sheet can be glued to the opening of the housing 1 using epoxy resin as the signal transmission window 8.

[0028] Figure 3 This is a schematic cross-sectional view of a circuit board according to an embodiment of this application. See also... Figure 2 and Figure 3 The circuit board 2 can be a high-density circuit board, employing at least an 8-layer buried via wiring structure. In this embodiment, the circuit board 2 adopts an 8-layer buried via wiring structure. From top to bottom, layers 1 and 8 are high-frequency signal layers, used to lay high-frequency signal lines for core components such as the microprocessor 3 and the wireless communication module 4. The line width is 0.2mm to 0.3mm, and the line spacing is not less than 0.2mm to reduce signal crosstalk. Layers 2 and 7 are ground layers, using complete copper foil layers, with a grounding resistance less than or equal to 0.05Ω, which can quickly absorb interference signals in the circuit and form a stable ground reference plane. Layers 3 and 6 are 3.3V power layers, interconnected with the ground layer through multiple 0.3mm diameter vias, with a via density of 4 to 6 per square centimeter to ensure stable current transmission and avoid voltage drops. Layers 4 and 5 are inner signal layers, used to transmit low-speed control signals.

[0029] For example, the substrate material of circuit board 2 can be FR-4 epoxy glass cloth substrate with a thickness of 1.6mm, which has excellent high temperature resistance and insulation properties.

[0030] Optionally, the circuit board 2 is a rectangular circuit board, and the embedded planar inverted F antenna 5 and the power management circuit 7 are arranged on opposite sides of the microprocessor 3 along the diagonal direction of the circuit board 2.

[0031] For example, the minimum distance between the embedded planar inverted-F antenna 5 and the power management circuit 7 is greater than or equal to 5 mm and less than or equal to 70 mm. Here, the minimum distance refers to the minimum value of the distance between the embedded planar inverted-F antenna 5 and the power management circuit 7. For example, the minimum distance between the radiating edge of the embedded planar inverted-F antenna 5 and the components of the power management circuit 7 is greater than or equal to 5 mm and less than or equal to 70 mm. In this embodiment, the minimum distance between the embedded planar inverted-F antenna 5 and the power management circuit 7 is 60 mm. This can minimize the interference of the noise of the power management circuit 7 on the antenna radiation performance.

[0032] For example, microprocessor 3 can be a 32-bit ARM Cortex-M4 core chip of model STM32L476RGT6. This chip can operate at a maximum frequency of 80MHz, has 1MB of Flash memory and 128KB of Random Access Memory (RAM), supports low-power mode, and can meet the device's long standby and data processing requirements. For instance, microprocessor 3 can connect to wireless communication module 4 through its Serial Peripheral Interface (SPI) to achieve data interaction, and through its I... 2 The C interface connects to the sensor interface 6, and a Universal Asynchronous Receiver / Transmitter (UART) interface is reserved for debugging and firmware upgrades. A 47pF ceramic filter capacitor and a 10nF decoupling capacitor are placed around the chip to suppress the impact of power supply noise on the stability of the microprocessor 3.

[0033] For example, the wireless communication module 4 can be a LoRa wireless transceiver chip of model SX1278. This module operates in a frequency band covering 868MHz to 915MHz, with a maximum transmit power of 17dBm, a receive sensitivity of -148dBm, and a communication distance of up to 5km in open environments, meeting the needs of remote data transmission for the Internet of Things.

[0034] For example, the embedded planar inverted-F antenna 5 operates in a frequency band covering 868MHz to 915MHz.

[0035] Optionally, the feed point of the radiator of the embedded planar inverted-F antenna 5 is connected to the wireless communication module 4 via a π-type impedance matching circuit. For example, the feed point of the radiator of the embedded planar inverted-F antenna 5 can be connected to the wireless communication module 4 via a π-type impedance matching circuit consisting of two inductors (1nH, 10nH) and one capacitor (22pF) and a microstrip line with an impedance of 50Ω. The π-type impedance matching circuit ensures that the input impedance of the embedded planar inverted-F antenna 5 is stabilized at 50Ω (matching the module's output impedance) in the 868MHz to 915MHz frequency band, with an antenna VSWR less than or equal to 1.5 and a radiation efficiency greater than or equal to 75%, reducing feeder loss, ensuring efficient wireless signal transmission, and improving wireless communication quality.

[0036] For example, the embedded planar inverted-F antenna 5 can be fabricated on the first high-frequency signal layer of the circuit board 2 using a copper foil etching process. The radiator of the embedded planar inverted-F antenna 5 can be 25mm × 15mm in size. The grounding part is interconnected with the second grounding layer of the circuit board 2 through four vias to ensure good grounding.

[0037] For example, the sensor interface 6 can adopt a standard 485 bus interface design, including 4 terminals (VCC, GND, A, B) and a transient voltage suppressor (TVS) diode of model SMBJ6.5CA. The TVS is connected in parallel between pins A and B and can absorb transient voltages of ±6.5V to prevent damage to the circuit caused by static electricity or surges introduced when external sensors are plugged in or unplugged or when long cables are transmitted.

[0038] For example, the sensor interface 6 can be connected to the circuit board 2 via a 2.54mm pitch terminal block, and its signal lines are transmitted to the microprocessor 3 via the fifth inner signal layer of the circuit board 2. 2 The Type-C interface features a 100Ω current-limiting resistor in series and a 0.1μF filter capacitor in parallel to effectively suppress line noise. Sensor interface 6 supports up to 8 external sensors simultaneously, with each sensor operating at a current of less than or equal to 50mA, meeting the needs of multi-parameter monitoring scenarios.

[0039] Figure 4 This is a schematic diagram of a power management circuit provided in an embodiment of this application. See also... Figure 2 and Figure 4 The power management circuit 7 includes a step-down voltage regulator unit 9, a dynamic power consumption adjustment unit 10, and a battery protection unit 11 connected in sequence.

[0040] For example, the buck regulator unit 9 can be a synchronous buck chip of model MP2307. This chip has an input voltage of 5V to 28V, and the output voltage can be adjusted by an external resistor (e.g., 3.3V). The maximum output current can reach 3A, and the conversion efficiency is greater than or equal to 90% (greater than or equal to 85% in light load mode). The chip is surrounded by a 22μF input filter capacitor (electrolytic capacitor), a 10μF output filter capacitor (ceramic capacitor), and a 2.2μH inductor to ensure that the output voltage ripple is less than or equal to 50mV, which can provide a stable voltage for the subsequent circuits.

[0041] For example, the dynamic power consumption adjustment unit 10 is electrically connected to the general purpose input / output (GPIO) pin of the microprocessor 3, and is used to adjust the circuit power consumption according to the signals of the microprocessor 3.

[0042] Optionally, the dynamic power consumption regulation unit 10 includes a MOSFET switch array 12 and a reference voltage source 13. The MOSFET switch array 12 is used to selectively disconnect the power supply circuit of the sensor interface 6.

[0043] For example, the MOSFET switch array 12 includes multiple P-channel MOSFETs connected in parallel. Each P-channel MOSFET corresponds to a power supply circuit of the sensor interface 6, and the gate of the P-channel MOSFET is connected to the microprocessor 3. For instance, the MOSFET switch array 12 may include four P-channel MOSFETs connected in parallel. The gate of each P-channel MOSFET is connected to the GPIO pin of the microprocessor 3 through a 1kΩ resistor. When the microprocessor 3 detects that a certain sensor does not need to work (such as during interval sampling), it can output a high-level signal to turn off the corresponding P-channel MOSFET, thereby disconnecting the power supply circuit of that sensor. Powering off a single sensor can reduce power consumption by approximately 30μA.

[0044] It should be noted that the software functions used in this solution are existing technologies or standard industry practices. The innovation of this solution lies not in the program itself, but in how to integrate these conventional software functions with physical devices into a dedicated collaborative control system through specific hardware configurations and connection structures.

[0045] For example, the output accuracy of the reference voltage source 13 is within ±0.5%.

[0046] In this embodiment, the reference voltage source 13 can be a high-precision voltage reference chip of model REF3233. This chip outputs a voltage of 3.3V with an output accuracy of ±0.2% and a temperature drift coefficient of less than or equal to 5ppm / ℃ (within the range of -40℃ to 85℃). The chip is filtered by a 100nF ceramic capacitor, which can provide a stable voltage reference for the power management circuit 7, ensuring that the output voltage accuracy of the buck regulator unit 9 is controlled within ±1%, thereby avoiding voltage fluctuations from affecting the working stability of the microprocessor 3 and the wireless communication module 4.

[0047] For example, the battery protection unit 11 can be an S8261 type lithium battery protection chip. This chip supports overcharge protection, over-discharge protection and overcurrent protection for a single lithium battery. The chip controls the battery circuit through two AO3400 N-channel MOSFETs. When an abnormal state is detected, the circuit can be cut off within 100μs to prevent battery damage or fire risk.

[0048] In this embodiment, the power management circuit 7 utilizes a combination of a step-down voltage regulator unit 9, a dynamic power consumption adjustment unit 10, and a battery protection unit 11, along with the low-power mode of the microprocessor 3, to effectively reduce power consumption and significantly improve the battery life of the wireless IoT terminal device. For example, with a 2000mAh lithium battery, the battery life of the wireless IoT terminal device can be extended from the conventional 6 months to 8 months, better meeting the needs of long-term unattended deployments of the IoT.

[0049] The above description is merely an optional embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A wireless Internet of Things (IoT) terminal device, characterized in that, Includes a housing and a circuit board disposed within the cavity of the housing, wherein the circuit board integrates: microprocessor; A wireless communication module is electrically connected to the microprocessor, and an embedded planar inverted-F antenna is connected to the wireless communication module. A sensor interface, electrically connected to the microprocessor, is used to connect external sensors; A power management circuit, electrically connected to the microprocessor and the sensor interface, is used to supply power to the microprocessor and the wireless communication module and can selectively disconnect the power supply circuit of the sensor interface; The embedded planar inverted-F antenna and the power management circuit are located on opposite sides of the microprocessor, and the sensor interface is located on the side of the power management circuit furthest from the microprocessor.

2. The wireless Internet of Things terminal device according to claim 1, characterized in that, The circuit board is a rectangular circuit board, and the embedded planar inverted-F antenna and the power management circuit are respectively arranged on opposite sides of the microprocessor along the diagonal direction of the circuit board.

3. The wireless Internet of Things terminal device according to claim 2, characterized in that, The minimum distance between the embedded planar inverted-F antenna and the power management circuit is greater than or equal to 5 mm and less than or equal to 70 mm.

4. The wireless Internet of Things terminal device according to claim 1, characterized in that, The feed point of the radiator of the embedded planar inverted-F antenna is connected to the wireless communication module through a π-type impedance matching circuit.

5. The wireless Internet of Things terminal device according to any one of claims 1 to 4, characterized in that, The power management circuit includes a buck regulator unit, a dynamic power consumption adjustment unit, and a battery protection unit connected in sequence.

6. The wireless Internet of Things terminal device according to claim 5, characterized in that, The dynamic power consumption adjustment unit includes a MOSFET switch array and a reference voltage source. The MOSFET switch array is used to selectively disconnect the power supply circuit of the sensor interface.

7. The wireless Internet of Things terminal device according to claim 6, characterized in that, The MOS transistor switch array includes multiple P-channel MOS transistors arranged in parallel. Each P-channel MOS transistor corresponds to a power supply circuit of the sensor interface, and the gate of the P-channel MOS transistor is connected to the microprocessor.

8. The wireless Internet of Things terminal device according to any one of claims 1 to 4 and claims 6 to 7, characterized in that, The shell is made of galvanized cold-rolled steel sheet.

9. The wireless Internet of Things terminal device according to claim 8, characterized in that, A signal pass-through window is provided on the housing at the corresponding position in the area where the embedded planar inverted-F antenna is located. The signal pass-through window is used to suppress the attenuation of the antenna signal.

10. The wireless Internet of Things terminal device according to claim 9, characterized in that, The material of the signal transmission window is polytetrafluoroethylene.

Images