CN210693924U - Terminal module based on loRa - Google Patents

Abstract

The utility model discloses a terminal module based on loRa belongs to wireless communication technical field. The terminal module based on the LoRa comprises an ASR6505 chip, a second-order LC impedance matching circuit, a second-order Gaussian low-pass filter, a second-order Bessel band-pass filter, a radio frequency switch chip, a balun balancer circuit, a crystal oscillator matching circuit and a power supply filter circuit. The second-order LC impedance matching circuit matches the impedance of the radio frequency output pin of the ASR6505 chip to 50 ohms; the second-order Gaussian low-pass filter filters the radio-frequency signal, so that low frequency is guaranteed to pass through and part of high-frequency harmonic waves are suppressed; the second-order Bessel type band-pass filter further inhibits high-frequency harmonics in the radio-frequency signals output from the second-order Gaussian type low-pass filter; the radio frequency switch chip ensures that the module is stable and reliable in working paths in different modes; the balun balancer circuit converts the received single-channel radio-frequency signal into a differential signal, and then transmits the differential signal to an ASR6505 chip for processing; the crystal oscillator matching circuit and the power supply filter circuit are both connected with the ASR6505 chip.

Description

Terminal module based on loRa

Technical Field

The utility model relates to a wireless communication technical field, in particular to terminal module based on loRa.

Background

In recent years, with the continuous popularization of the ultra-long distance transmission technology LoRa, more and more industries begin to use the ultra-long distance transmission technology LoRa as a main communication solution, and the ultra-long distance transmission technology LoRa plays a key role in directions of four watches, security protection, agriculture and the like.

The LoRa module in the current market has larger size, and is very unfavorable for the research and development and production of portable equipment; peripheral components are more, and whole module cost is higher, is unfavorable for the marketing of module.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a terminal module based on loRa to solve the great, the high problem of cost of manufacture of loRa module size.

In order to solve the technical problem, the utility model provides a terminal module based on loRa, include:

an ASR6505 chip;

the second-order LC impedance matching circuit is used for matching the impedance of the radio frequency output pin of the ASR6505 chip to 50 ohms;

the second-order Gaussian low-pass filter is connected with the second-order LC impedance matching circuit and is used for filtering the radio-frequency signal, ensuring that low frequency passes and inhibiting partial high-frequency harmonic;

the second-order Bessel type band-pass filter is used for further inhibiting high-frequency harmonics in the radio-frequency signals output from the second-order Gaussian type low-pass filter;

the radio frequency switch chip ensures the stability and reliability of the working path of the module in different modes under the control of the ASR6505 chip;

the balun balancer circuit is connected with the ASR6505 chip and the radio frequency switch chip, converts a received single-channel radio frequency signal into a differential signal, and then transmits the differential signal to the ASR6505 chip for processing;

and the crystal oscillator matching circuit and the power supply filter circuit are connected with the ASR6505 chip.

Optionally, the ASR6505 chip is internally integrated with an MCU and an LoRa radio frequency chip.

Optionally, the crystal oscillator matching circuit includes two specifications of a 32MHz crystal oscillator and a 32.768KHz crystal oscillator; wherein,

the 32MHz crystal oscillator provides frequency multiplication basic frequency for the transmitting and receiving work of a LoRa radio frequency chip in the ASR6505 chip;

the 32.768KHz crystal oscillator provides a frequency reference for the timer work of the MCU in the ASR6505 chip.

Optionally, both power supply and control pins of the radio frequency switch chip are connected to the ASR6502 chip, and the ASR6502 chip supplies power to the radio frequency switch chip and controls a circuit gating path thereof.

Optionally, the terminal module based on LoRa adopts stamp half-hole LCC encapsulation.

Optionally, terminal module based on loRa adopts welded metal shielding cover to carry out laser printing to module model, serial number on metal shielding cover.

The utility model provides a terminal module based on loRa has following beneficial effect:

(1) the size of the module is reduced through the SIP packaging technology, and compared with a traditional separated LoRa chip and a general MCU, the problems of overlarge size and higher manufacturing cost are greatly reduced;

(2) the method provides better module selection for an application scheme which needs to use a standard LoRaWan protocol and does not need to add an additional single chip microcomputer or other peripherals.

Drawings

Fig. 1 is a schematic diagram of a principle structure of a terminal module based on LoRa provided by the present invention;

FIG. 2 is a schematic view of the outline of a module;

fig. 3 is a schematic diagram of a module pad.

Detailed Description

The terminal module based on LoRa of the present invention is further described in detail with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more fully apparent from the following description and appended claims. It should be noted that the drawings are in simplified form and are not to precise scale, and are provided for convenience and clarity in order to facilitate the description of the embodiments of the present invention.

Example one

The utility model provides a terminal module based on loRa, its principle structure is as shown in figure 1, including ASR6505 chip 1, second order LC impedance matching circuit 2, second order Gaussian type low pass filter 3, second order Bessel type band pass filter 4, radio frequency switch chip 5, balun equalizer circuit 6, crystal oscillator matching circuit 7 and power filter circuit 8. The ASR6505 chip 1, the second-order LC impedance matching circuit 2, the second-order Gaussian low-pass filter 3, the second-order Bessel band-pass filter 4, the radio frequency switch chip 5 and the balun balancer circuit 6 are connected in sequence; the crystal oscillator matching circuit 7 and the power supply filter circuit 8 are connected with the ASR6505 chip 1, and the radio frequency switch chip 5 is controlled by the ASR6505 chip 1.

The general MCU chip and the LoRa radio frequency chip are packaged by the SIP inside the ASR6505 chip 1, compared with the traditional split MCU + LoRa chip scheme, the chip has remarkable volume advantage, and can ensure all frequency bands and power output of the LoRa technology; the second-order LC impedance matching circuit 2 is connected with the ASR6505 chip 1, and in order to achieve the optimal output of the radio frequency circuit, the second-order LC impedance matching circuit 2 matches the impedance parameters of the radio frequency output pin of the ASR6505 chip 1 to the radio frequency general 50-ohm impedance; the second-order Gaussian low-pass filter 3 is connected with the second-order LC impedance matching circuit 2, when a radio-frequency signal is sent out, harmful high-frequency harmonics still exist except for a desired frequency, and the second-order Gaussian low-pass filter 3 is designed into a 50-ohm characteristic impedance low-pass filter, so that the harmful high-frequency harmonics can be reduced to a certain extent under the condition of ensuring a pass band; the second-order bessel type band-pass filter 4 is connected with the second-order gaussian type low-pass filter 3, and the signal output from the second-order gaussian type low-pass filter 3 cannot reduce harmful high-frequency harmonic waves to a desired value only by the second-order gaussian type low-pass filter 3 because the attenuation of the second-order gaussian type low-pass filter 3 in a stop band is slow, so that the harmful high-frequency harmonic waves are further reduced to reach the desired value while the pass band is ensured by the aid of the first-order 50-ohm characteristic impedance second-order bessel type band-pass filter 4; the radio frequency switch chip 5 is connected with the second-order Bessel band-pass filter 4 and is controlled by the ASR6505 chip 1, and the radio frequency switch chip 5 can switch and connect a part of circuits of a radio frequency common path to independent branches required by different working states of the module according to different working states of the module, so that the stability and reliability of the working paths of the module in different modes are ensured; the balun balancer circuit 6 is connected with the ASR6505 chip 1 and the radio frequency switch chip 5, and because the receiving circuit part of the ASR6505 chip 1 is differential input, the balun balancer circuit 6 converts a received single-channel radio frequency signal into a differential signal, and then the differential signal is subjected to signal processing by the ASR6505 chip 1; the crystal oscillator matching circuit 7 and the power supply filter circuit 8 are both connected with the ASR6505 chip 1, the crystal oscillator matching circuit 7 comprises two specifications of a 32MHz crystal oscillator and a 32.768KHz crystal oscillator, wherein the 32MHz crystal oscillator serves a LoRa radio frequency chip integrated in the ASR6505 chip 1 and provides frequency multiplication basic frequency for transmitting and receiving work of the chip, and the 32.768KHz crystal oscillator serves a general MCU in the ASR6505 chip 1 and provides frequency reference for the work of a timer of the MCU; the power supply filter circuit 8 supplies power to the ASR6505 chip 1 for filtering, so that lower ripple waves of power supply input of the ASR6505 chip are ensured, and the receiving state sensitivity of the ASR6505 chip is increased.

Flash and Ram integrated in the ASR6505 chip 1 have relatively small space, the module is a software open type module, is concentrated on a simple low-code-quantity non-LoRaWan protocol and adopts an application scene of a private LoRa communication protocol, maximum IO pins are led out, controllable peripheral devices are more, the size of the module is reduced through SIP integration, and the application scene of the module is greatly improved. In addition, the terminal module based on the LoRa adopts a stamp half-hole LCC package which is more beneficial to machine SMT processing than a traditional direct-insertion mode; and for the work influence that reduces module radio frequency circuit external stray radiation and external environment stray radiation module, adopt welded type metal shield cover design to the module to carry out laser printing to module model, serial number etc. on metal shield cover, increased the aesthetic property of module when guaranteeing module operational reliability.

The above description is only for the preferred embodiment of the present invention and is not intended to limit the scope of the present invention, and any modification and modification made by those skilled in the art according to the above disclosure are all within the scope of the claims.

Claims (6)

1. The utility model provides a terminal module based on loRa, its characterized in that includes:

an ASR6505 chip (1);

the second-order LC impedance matching circuit (2) is used for matching the impedance of the radio frequency output pin of the ASR6505 chip (1) to 50 ohms;

the second-order Gaussian low-pass filter (3) is connected with the second-order LC impedance matching circuit (2) and is used for filtering radio frequency signals, ensuring that low frequency passes through and inhibiting partial high-frequency harmonic waves;

a second-order Bessel-type band-pass filter (4) for further suppressing high-frequency harmonics in the radio-frequency signal output from the second-order Gaussian-type low-pass filter (3);

the radio frequency switch chip (5) ensures the stability and reliability of the working path of the module in different modes under the control of the ASR6505 chip (1);

the balun balancer circuit (6) is connected with the ASR6505 chip (1) and the radio frequency switch chip (5), converts a received single-channel radio frequency signal into a differential signal, and then transmits the differential signal to the ASR6505 chip (1) for processing;

and the crystal oscillator matching circuit (7) and the power supply filter circuit (8) are connected with the ASR6505 chip (1).

2. The LoRa-based terminal module according to claim 1, wherein the ASR6505 chip (1) is internally integrated with an MCU and a LoRa radio frequency chip.

3. The LoRa-based termination module of claim 2, wherein the crystal oscillator matching circuit (7) comprises two specifications of a 32MHz crystal oscillator and a 32.768KHz crystal oscillator; wherein,

the 32MHz crystal oscillator provides frequency multiplication basic frequency for the transmitting and receiving work of a LoRa radio frequency chip in the ASR6505 chip (1);

the 32.768KHz crystal oscillator provides a frequency reference for the timer work of the MCU in the ASR6505 chip (1).

4. The LoRa-based terminal module according to claim 1, wherein both the power supply and control pins of the rf switch chip (5) are connected to the ASR6502 chip (1), and the ASR6502 chip (1) supplies power to the rf switch chip (5) and controls the circuit gating path thereof.

5. A LoRa-based terminal module according to any one of claims 1 to 4, characterised in that the LoRa-based terminal module is encapsulated with a postage stamp half-hole LCC.

6. The LoRa-based terminal module of any of claims 1-4, wherein the LoRa-based terminal module is a welded metal shield, and the module model and number are laser printed on the metal shield.

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