Communication module applied to intelligent terminal and level matching circuit thereof

Abstract

The utility model relates to a communication module applied to an intelligent terminal and a level matching circuit thereof. A collector electrode of the triode is used for being connected with a signal receiving end of the microcontroller, an emitting electrode is used for being connected with a signal sending end of the long-term evolution module, a base electrode is used for being connected with a high level, and level matching of a sending signal of the long-term evolution module and a receiving signal of the microcontroller can be achieved; an anode of a first diode is used for being connected with a signal receiving end of a long-term evolution module and accessing a high level, and a cathode of the first diode is used for being connected with a signal sending end of a microcontroller, so that level matching between a sending signal of the microcontroller and a receiving signal of the long-term evolution module can be realized; moreover, the level matching circuit is simple in structure, is not limited by device models, is wide in adaptation range, can be flexibly applied to various communication modules, and is high in flexibility. In addition, the level matching circuit occupies a small circuit board area and is suitable for miniaturization design.

Description

Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a communication module and a level matching circuit thereof applied to a smart terminal. Background Art

[0002] With the widespread adoption of IoT technology, reliable wireless communication can be achieved between electronic devices. In scenarios with strict requirements for real-time transmission and reliability, or where large amounts of data are transmitted, wireless communication based on Long Term Evolution (LTE) modules is often used. The serial port level of LTE modules is mostly LVTTL (Low-Voltage Transistor-Transistor Logic), which prevents direct communication between the microcontroller unit (MCU) and the LTE module and requires level conversion. However, traditional level conversion methods offer limited circuit flexibility. Utility Model Content

[0003] Based on this, it is necessary to provide a communication module and a level matching circuit thereof with high flexibility for use in smart terminals.

[0004] In a first aspect, a level matching circuit is provided for use in a communication module, the communication module including a microcontroller and a long-term evolution module, the level matching circuit including:

[0005] Transistor, the collector of the transistor is used to connect to the signal receiving end of the microcontroller, the emitter of the transistor is used to connect to the signal sending end of the long-term evolution module, and the base of the transistor is used to access the high level;

[0006] A first diode, wherein the anode of the first diode is used to connect to the signal receiving end of the long term evolution module and access the high level, and the cathode of the first diode is used to connect to the signal sending end of the microcontroller.

[0007] In one embodiment, the level matching circuit further includes:

[0008] a first pull-up resistor, one end of the first pull-up resistor being connected to a signal receiving terminal of the microcontroller, and the other end of the first pull-up resistor being used to access an operating voltage;

[0009] A second pull-up resistor is connected in series between the anode of the first diode and the high-level receiving end.

[0010] In one embodiment, the high level matches the voltage amplitude of the long term evolution module.

[0011] In one embodiment, the level matching circuit further includes:

[0012] A third pull-up resistor, one end of the third pull-up resistor is connected to the cathode of the first diode, and the other end of the third pull-up resistor is used to access the working voltage.

[0013] In one embodiment, the level matching circuit further includes:

[0014] A first resistor, one end of the first resistor is connected to the base of the transistor, and the other end of the first resistor is used to access a high level.

[0015] In one embodiment, the level matching circuit further includes:

[0016] A second resistor, wherein a first end of the second resistor is used to access a high level, and a second end of the second resistor is connected to the anode of the first diode.

[0017] In one embodiment, the level matching circuit further includes:

[0018] The second diode is connected in series in a forward direction to the second resistor and the signal receiving end of the long term evolution module.

[0019] In one embodiment, the first diode and the second diode are packaged as bidirectional diodes.

[0020] In a second aspect, a communication module applied to a smart terminal is provided, comprising a microcontroller, a long term evolution module and the above-mentioned level matching circuit.

[0021] In one embodiment, the high level is a power signal output by the long term evolution module.

[0022] The above-mentioned communication module and level matching circuit applied to the smart terminal are based on the fact that the collector of the transistor is used to connect to the signal receiving end of the microcontroller, the emitter is used to connect to the signal sending end of the long-term evolution module, and the base is used to access the high level, which can achieve level matching between the sending signal of the long-term evolution module and the receiving signal of the microcontroller; based on the anode of the first diode is used to connect to the signal receiving end of the long-term evolution module and access the high level, and the cathode is used to connect to the signal sending end of the microcontroller, which can achieve level matching between the sending signal of the microcontroller and the receiving signal of the long-term evolution module; and the level matching circuit has a simple structure, no device model restrictions, and a wide range of adaptability, so it can be flexibly applied to various communication modules and has high flexibility; in addition, the level matching circuit occupies a small circuit board area and is suitable for miniaturized design. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the conventional technology, the following briefly introduces the drawings required for use in the embodiments or the conventional technology descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 A structural block diagram of a traditional level matching circuit based on a level converter according to an embodiment;

[0025] Figure 2 A block diagram of a conventional level matching circuit constructed based on discrete components according to an embodiment;

[0026] Figure 3 A signal simulation diagram of a traditional level matching circuit constructed based on discrete components according to an embodiment;

[0027] Figure 4 A block diagram of a conventional level matching circuit based on a discrete component two-level control architecture according to an embodiment;

[0028] Figure 5 This is one of the structural block diagrams of a level matching circuit according to an embodiment;

[0029] Figure 6 This is a second structural block diagram of a level matching circuit according to an embodiment;

[0030] Figure 7 is a simulation result of an embodiment without including the second diode;

[0031] Figure 8 FIG1 is a simulation diagram of a microcontroller outputting a sending signal when a second diode is included in an embodiment;

[0032] Figure 9 FIG. 1 is a simulation diagram of an output signal of a long-term evolution module when a second diode is included according to an embodiment. DETAILED DESCRIPTION

[0033] To facilitate understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The accompanying drawings provide embodiments of the present application. However, the present application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to make the disclosure of the present application more thorough and comprehensive.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0035] It will be understood that the terms "first," "second," and the like, as used herein, may be used to describe various elements herein, but these elements are not limited by these terms. These terms are used solely to distinguish a first element from another element. For example, a first diode may be referred to as a second diode, and similarly, a second diode may be referred to as a first diode, without departing from the scope of this application. The first diode and the second diode are both diodes, but they are not the same diode.

[0036] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if there is transmission of electrical signals or data between the connected circuits, modules, units, etc.

[0037] It is understood that “at least one” refers to one or more, “a plurality” refers to two or more, and “at least a portion of an element” refers to a portion or all of an element.

[0038] When used herein, the singular forms "a", "an", and "the" may also include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof.

[0039] In traditional technology, the level matching between the microcontroller and the LTE module is achieved by Figure 1 This is achieved using the level converter shown in the figure. Specifically, the level standard on the LTE module side meets the LTE module's (0, 1) judgment standard. Correspondingly, the level standard on the microcontroller side also meets the microcontroller's (0, 1) judgment standard. The level converter is enabled via the OE port, allowing the LTE module on the VCCA side of the level converter to communicate with the microcontroller on the VCCB side, thereby ensuring logical consistency between the LTE module and the microcontroller. However, this level matching circuit is limited by specific chip models and requires reliance on specific chips from specific suppliers, resulting in high costs and a limited range of applications.

[0040] The level matching between the microcontroller and the LTE module can also be achieved by Figure 2 The traditional level matching circuit under the discrete component architecture shown in the figure is implemented. Figure 2 The microcontroller in Figure 2 When the TXD signal of device A) in Figure 2 The RXD (Receive Data) signal of device B) in the LTE module changes accordingly; correspondingly, when the TXD (Transmit Data) signal of the LTE module changes, the RXD signal of the microcontroller changes accordingly, thus achieving level matching. Figure 3 As shown, when the transistors in this level matching circuit are on for a long time, there will be a signal overshoot problem, thereby affecting the long-term reliability of the level matching circuit.

[0041] The level matching between the microcontroller and the LTE module can also be achieved by Figure 4 The traditional level matching circuit under the discrete component two-level control architecture shown in the figure is realized. Figure 3 When the MCU_UTXD signal (i.e., the microcontroller's TXD signal) changes, the RXD signal (i.e., the LTE module's RXD signal) changes accordingly; when the TXD signal (i.e., the LTE module's TXD signal) changes, the MCU_URXD signal (i.e., the microcontroller's RXD signal) changes accordingly, thus achieving level matching. However, the transistors in this level matching circuit can experience signal overshoot if the on-time is long. Furthermore, this level matching circuit involves many components and requires a large circuit board area, which poses significant limitations in applications with limited circuit board space requirements.

[0042] In one embodiment, Figure 5 As shown, a level matching circuit 10 is provided, which is applied to a communication module. The communication module includes a microcontroller and a long-term evolution module. The level matching circuit 10 includes: a transistor 102 and a first diode 104 .

[0043] The collector of the transistor 102 is used to connect to the signal receiving terminal of the microcontroller (such as Figure 5 The RXD terminal shown in FIG1 is connected to the emitter of the transistor 102 and is used to connect to the signal sending terminal of the long-term evolution module (such as Figure 5 TXD_N terminal shown), the base of transistor 102 (such as Figure 5 The VDD_EXT_1V8 terminal shown in the figure is used to access the high level.

[0044] Because the base of transistor 102 is connected to a high level, when the emitter of transistor 102 is at a logic 1, the emitter and base of transistor 102 are at the same potential, causing transistor 102 to be in the off state. Furthermore, because the collector of transistor 102 is connected to the signal receiving terminal of the microcontroller, and the microcontroller is in a high level state when in operation, the RXD terminal is correspondingly at a high level. Correspondingly, when the emitter of transistor 102 is at a logic 0, the base potential of transistor 102 is higher than the emitter potential, causing transistor 102 to be in the on state, causing the RXD terminal to be pulled down to a low level.

[0045] The anode of the first diode 104 is used to connect to the signal receiving end of the long-term evolution module (such as Figure 5 The cathode of the first diode 104 is used to connect to the signal sending end of the microcontroller (such as the RXD_N end shown in FIG. Figure 5 The first diode 104 may be a Schottky diode.

[0046] When the microcontroller is operating at a high level, the corresponding TXD terminal represents a logic 1, and the anode of the first diode 104 is connected to a high level. Due to the unidirectional conduction function of the first diode 104, the first diode 104 is cut off, and the RXD_N terminal, due to the high level of the VDD_EXT_1V8 terminal, represents a high level logic 1. Correspondingly, when the TXD terminal represents a low level, due to the unidirectional conduction function of the first diode 104, the first diode 104 is turned on, and the corresponding signal at the RXD_N terminal is clamped to a low amplitude range due to the forward conduction voltage drop of the first diode 104. The signal within this low amplitude range can be represented as a logic 0. For example, when the VDD_EXT_1V8 terminal is connected to 1.8V and the operating voltage of the microcontroller is 3.3V, the corresponding low amplitude range is 0.2V-0.3V.

[0047] Therefore, the above-mentioned level matching circuit 10, based on the collector of the transistor 102 being connected to the signal receiving end of the microcontroller, the emitter being connected to the signal transmitting end of the long-term evolution module, and the base being connected to a high level, can achieve level matching between the transmission signal of the long-term evolution module and the reception signal of the microcontroller; based on the anode of the first diode 104 being connected to the signal receiving end of the long-term evolution module and connected to a high level, and the cathode being connected to the signal transmitting end of the microcontroller, can achieve level matching between the transmission signal of the microcontroller and the reception signal of the long-term evolution module; and the level matching circuit 10 has a simple structure, no device model restrictions, and a wide range of adaptability, so it can be flexibly applied to various communication modules and has high flexibility. In addition, the level matching circuit 10 occupies a small circuit board area, suitable for miniaturized design.

[0048] In one embodiment, Figure 6 As shown, the level matching circuit 10 further includes a first pull-up resistor 106 and a second pull-up resistor 108 .

[0049] One end of the first pull-up resistor 106 is connected to a signal receiving terminal of the microcontroller, and the other end of the first pull-up resistor 106 is used to access an operating voltage.

[0050] The second pull-up resistor 108 is connected in series between the anode of the first diode 104 and the high-level receiving terminal.

[0051] The first pull-up resistor 106 can ensure that the RXD terminal is at a high level corresponding to the working voltage when the transistor 102 is not turned on, thereby preventing the signal at the RXD terminal from floating and improving the stability of the signal.

[0052] Similar to the first pull-up resistor 106 , the second pull-up resistor 108 can ensure that the RXD_N terminal is at a high level connected to the VDD_EXT_1V8 terminal when the first diode 104 is not conducting, thereby preventing the signal at the RXD_N terminal from floating and improving signal stability.

[0053] In one embodiment, the high level matches the voltage amplitude of the long term evolution module.

[0054] When the high level connected to the base of the transistor 102 matches the voltage amplitude of the LTE module, the transmit signal output by the LTE module can be ensured to match the signal corresponding to the TXD_N terminal without voltage conversion, thus simplifying the circuit.

[0055] In one embodiment, Figure 6 As shown, the level matching circuit 10 further includes a third pull-up resistor 110 .

[0056] One end of the third pull-up resistor 110 is connected to the cathode of the first diode 104 , and the other end of the third pull-up resistor 110 is used to access the operating voltage.

[0057] Similar to the first pull-up resistor 106 , the third pull-up resistor 110 can ensure that the TXD terminal is at a high level corresponding to the operating voltage when the first diode 104 is not conducting, thereby preventing the signal at the TXD terminal from floating and improving signal stability.

[0058] In one embodiment, Figure 6 As shown, the level matching circuit 10 further includes a first resistor 112 .

[0059] One end of the first resistor 112 is connected to the base of the transistor 102 , and the other end of the first resistor 112 is used to access a high level.

[0060] The first resistor 112 functions as a current limiter to prevent excessive current from flowing into the microcontroller and the LTE module through the transistor 102 and provides a high-level voltage source, thereby improving the reliability of the level matching circuit 10 .

[0061] In one embodiment, Figure 6 As shown, the level matching circuit 10 further includes a second resistor 114 .

[0062] A first end of the second resistor 114 is used to access a high level, and a second end of the second resistor 114 is connected to the anode of the first diode 104 .

[0063] Similar to the first resistor 112 , the second resistor 114 functions as a current limiter to prevent excessive current from flowing into the LTE module and providing a high-level voltage source, and to prevent excessive current from flowing into the microcontroller via the first diode 104 , thereby improving the reliability of the level matching circuit 10 .

[0064] In one embodiment, Figure 6 As shown, the level matching circuit 10 further includes a second diode 116 .

[0065] The second diode 116 is connected in series in the forward direction to the second resistor 114 and the signal receiving end of the LTE module. The second diode 116 may be a Schottky diode.

[0066] Without the second diode 116, Figure 7 As shown, based on simulation experiments using simulation software such as Multisim and AltiumDesigner, it can be seen that the signal at the RXD_N end has an overshoot phenomenon.

[0067] like Figure 8 and Figure 9 As shown, after the second diode 116 is connected, the microcontroller sends a signal to the LTE module output. Overshoot, particularly negative overshoot, of the LTE module output signal is effectively suppressed, and voltages below 0V no longer occur. Specifically, when the voltage applied to the second diode 116 exceeds a certain threshold, it quickly turns on and clamps the excessive voltage to a certain level, thereby protecting downstream circuits from overshoot and providing circuit protection. Therefore, the aforementioned level matching circuit 10 also provides overshoot protection, thereby improving the stability of the communication signal and ensuring the long-term reliable operation of the level matching circuit 10.

[0068] In one embodiment, the first diode 104 and the second diode 116 are packaged as bidirectional diodes.

[0069] Using a packaged bidirectional diode can reduce the cost of the level matching circuit 10 .

[0070] In one embodiment, a communication module applied to a smart terminal is provided, including a microcontroller, a long term evolution module, and the level matching circuit 10 described above.

[0071] The communication module used in the smart terminal equipped with the level matching circuit 10 can ensure the communication reliability between the microcontroller and the long-term evolution module, and can also play a role in preventing overshoot.

[0072] In one embodiment, in the communication module applied to the smart terminal, the high level is a power signal output by the long term evolution module.

[0073] Directly connect the power signal output by the long-term evolution module to the Figure 5 and Figure 6 The VDD_EXT_1V8 terminal in the circuit can reduce the connection of the external power supply, thereby reducing the wiring of the circuit and simplifying the circuit.

[0074] In the description of this specification, reference to the terms "some embodiments" or "other embodiments" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

[0075] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0076] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A level matching circuit, characterized in that: Applied to a communication module, the communication module includes a microcontroller and a long-term evolution module, and the level matching circuit includes: A transistor, wherein the collector of the transistor is used to connect to the signal receiving end of the microcontroller, the emitter of the transistor is used to connect to the signal sending end of the long-term evolution module, and the base of the transistor is used to access a high level; A first diode, wherein the anode of the first diode is used to connect to the signal receiving end of the long-term evolution module and access the high level, and the cathode of the first diode is used to connect to the signal sending end of the microcontroller.

2. The level matching circuit according to claim 1, wherein: Also includes: a first pull-up resistor, one end of the first pull-up resistor being connected to a signal receiving terminal of the microcontroller, and the other end of the first pull-up resistor being used to access an operating voltage; A second pull-up resistor is connected in series between the anode of the first diode and the high-level receiving end.

3. The level matching circuit according to claim 1, wherein: The high level matches the voltage amplitude of the long term evolution module.

4. The level matching circuit according to claim 1, wherein: Also includes: a third pull-up resistor, one end of the third pull-up resistor being connected to the cathode of the first diode, and the other end of the third pull-up resistor being used for accessing an operating voltage.

5. The level matching circuit according to claim 1, wherein: Also includes: A first resistor, one end of the first resistor is connected to the base of the transistor, and the other end of the first resistor is used to access the high level.

6. The level matching circuit according to claim 1, wherein: Also includes: A second resistor, wherein a first end of the second resistor is used to access the high level, and a second end of the second resistor is connected to the anode of the first diode.

7. The level matching circuit according to claim 6, wherein: Also includes: A second diode is connected in series in a forward direction to the second resistor and a signal receiving end of the long term evolution module.

8. The level matching circuit according to claim 7, characterized in that: The first diode and the second diode are packaged as bidirectional diodes.

9. A communication module applied to a smart terminal, characterized in that: The device comprises a microcontroller, a long term evolution module and the level matching circuit according to any one of claims 1 to 8.

10. The communication module for smart terminals according to claim 9, characterized in that: The high level is a power signal output by the long term evolution module.

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