A UART communication isolation level conversion circuit

Abstract

The application belongs to the technical field of electronic application, and relates to a UART communication isolation level conversion circuit. The application comprises an external module and an internal module; an output end of the external module is connected with a triode Q1 through a voltage dividing resistor R1 and a resistor R11, the triode Q1 is connected with a triode Q2 through a resistor R3 and a resistor R4, the triode Q2 is connected with an input end of the internal module, a c pole of the Q1 is connected with a direct current power supply DC through a resistor R2, the resistor R2 and the direct current power supply DC are connected with a c pole of the triode Q2 through a diode Z1 and a resistor R5 in sequence; an output end of the internal module is connected with a triode Q4 through a resistor R10 and a resistor R12, the triode Q4 is connected with a triode Q3 through a resistor R8 and a resistor R7, the triode Q3 is connected with an input end of the external module, a c pole of the Q4 is connected with the direct current power supply DC through a resistor R9, the direct current power supply DC is connected with a c pole of the triode Q3 through a resistor R6, the application can realize effective transmission of electrical signals between the external module and the internal module, guarantee the stability of the level signal transmission, and avoid the problem of communication failure between different level module circuits.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electronic application, and relates to a UART communication isolation level conversion circuit. BACKGROUND

[0002] When it comes to communication between different module circuits, a common problem lies in the difference between the signal reference levels of internal modules and external modules. In circuit design, these modules are usually set to different signal reference levels according to their respective functions and working environments. However, when these two modules try to communicate directly through UART (Universal Asynchronous Receiver Transmitter), this level difference can cause the following problems.

[0003] Firstly, when the TX (Transmit) port of the internal module tries to send data to the RX (Receive) port of the external module, it generates a signal based on its internal reference level. However, if the TX output level of the internal module is lower than the high-level threshold that the external module RX can recognize, the external module will not be able to correctly interpret this signal, resulting in communication failure.

[0004] Secondly, when the TX port of the external module sends data, it generates a signal based on its high-level reference voltage. If this voltage exceeds the maximum withstand voltage of the RX port of the internal module, it can damage the receiver of the internal module, and even cause irreversible damage to the entire internal module.

[0005] In summary, when different module circuits try to communicate directly through UART (Universal Asynchronous Receiver Transmitter), the inconsistency of communication levels can cause communication failure problems, and even damage the receivers of circuit modules. SUMMARY

[0006] The purpose of the present application is to provide a UART communication isolation level conversion circuit to solve the technical problem that the inconsistency of communication levels between different module circuits can cause communication failure, and even damage the receivers of circuit modules. The present application can effectively transmit electrical signals between external modules and internal modules, ensure the stability of level signal transmission, and avoid the problem of communication failure between different level module circuits.

[0007] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0008] The present application discloses a UART communication isolation level conversion circuit, comprising an external module and an internal module.

[0009] The output end of the external module is connected with resistor R1, resistor R1 is connected with the b electrode of triode Q1 and resistor R11 respectively, resistor R11 is connected with the e electrode of triode Q1, the c electrode of triode Q1 is connected with the b electrode of triode Q2 through resistor R3, resistor R3 is connected with the c electrode of triode Q2 through resistor R4, the c electrode of triode Q2 is connected with the input end of the internal module, the c electrode of Q1 is connected with DC power supply DC through resistor R2, resistor R2 is connected with the c electrode of triode Q2 through diode Z1 and resistor R5 in sequence;

[0010] The output end of the internal module is connected with resistor R10, resistor R10 is connected with the b electrode of triode Q4 and resistor R12 respectively, resistor R12 is connected with the e electrode of triode Q4, the c electrode of triode Q4 is connected with the b electrode of triode Q3 through resistor R8, resistor R8 is connected with the c electrode of triode Q3 through resistor R7, the c electrode of triode Q3 is connected with the input end of the external module, the c electrode of Q4 is connected with DC power supply DC through resistor R9, DC power supply DC is connected with the c electrode of triode Q3 through resistor R6.

[0011] Further, the e electrodes of triode Q1, triode Q2, triode Q3 and triode Q4 are all grounded.

[0012] Further, the output end and the input end of the external module are both universal asynchronous receiver-transmitters.

[0013] Further, the output end and the input end of the internal module are both universal asynchronous receiver-transmitters.

[0014] Further, resistor R4 is connected with a first capacitor in parallel.

[0015] Further, resistor R7 is connected with a first capacitor in parallel.

[0016] Further, resistor R11 is connected with a second capacitor in parallel.

[0017] Further, resistor R12 is connected with a second capacitor in parallel.

[0018] Further, the first capacitor is 100PF.

[0019] Further, the second capacitor is 1NF.

[0020] Compared with the prior art, the present application has the following beneficial effects:

[0021] 1. The external module of the present application is used for connecting external circuits, and the internal module is used for connecting internal circuits.

[0022] R1 and R11 are used for high level voltage division in the circuit, so that the output end of the external module to the high and low level of triode Q1 is stable, R3 and R4 are used for high level voltage division in the circuit, so that the high and low level of triode Q1 to triode Q2 is stable, DC power supply DC provides high level signal to triode Q2 through resistor R2, when the external module uses the internal DC power supply DC as the pull-up, the one-way conductivity of diode Z1 is used to prevent the circuit from being connected, resistor R5 is mainly used for current limiting in the circuit, reduces the power consumption, prevents the input end of the internal DC power supply DC from being damaged, and further ensures that the electrical signal of the external circuit is effectively transmitted to the internal module, so that the influence of static electricity is avoided.

[0023] R10 and R12 are used for high level voltage division in the circuit, so that the output end of the internal module to the high and low level of triode Q4 is stable, R7 and R8 are used for high level voltage division in the circuit, so that the high and low level of triode Q4 to triode Q3 is stable, DC power supply DC provides high level signal to triode Q3 through resistor R9, DC power supply DC connects the c pole of triode Q3 through resistor R6, and further ensures that the electrical signal of the internal circuit is effectively transmitted to the external module, so that the influence of static electricity is avoided. The electrical signal input and output of the application are converted by two-stage triodes, the effective propagation of the original signal is realized, the communication signal is stable and safe, and the problem of communication failure between different level module circuits is avoided.

[0024] 2、The output end and the input end of the external module and the internal module of the application are all UART port conversion circuits, which can ensure that the communication signal is stable and safe. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is a whole structure schematic diagram of the application.

[0026] Among them: 1, external module; 2, internal module. DETAILED DESCRIPTION

[0027] In order to enable the personnel in the technical field to better understand the application scheme, the technical scheme in the embodiments of the application will be clearly and completely described below in combination with the drawings in the embodiments of the application. Obviously, the described embodiments are only a part of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by the person skilled in the art without creative labor should belong to the protection scope of the application.

[0028] It is to be understood that the terminology "first", "second", and the like used throughout this specification and the accompanying drawings is merely for distinguishing between similar objects of the application and is not necessarily for describing a particular sequential or chronological order. It is to be understood that the use of terminology such as top and bottom, front and rear, upper and lower, under and over, and the like is made for the purpose of this description only and is not intended to limit the scope of the application. It is also to be understood that the use of relational terms such as left, right, front, back, top, bottom, upper, lower, under and over and the like are used for the purpose of this description only and is not intended to limit the scope of the application. The terms "comprising", "having", "including", and "containing" are to be construed open-ended terms (i.e., meaning "including, but not limited to") unless otherwise noted. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any of the following "et", "exemplary", "for instance", "may", and "options" is intended to be the equivalent of the term "comprising". As used herein, the indefinite articles "a" and "an" are intended to mean one or more unless specified otherwise or calculated from the context to be singular only.

[0029] The application will be further described below in detail with reference to the drawings:

[0030] Referring to Figure 1 The application discloses a UART communication isolation level conversion circuit, which comprises an external module 1 and an internal module 2.

[0031] The output end of the external module 1 is connected with a resistor R1, the resistor R1 is connected with the b electrode of a triode Q1 and a resistor R11 respectively, the resistor R1 and the resistor R11 are used for high level voltage division in the circuit, so that the high and low levels of the output end of the external module 1 to the triode Q1 are stable, the resistor R11 is connected with the e electrode of the triode Q1, the c electrode of the triode Q1 is connected with the b electrode of a triode Q2 through a resistor R3, the resistor R3 and the triode Q2 are connected with the ground through a resistor R4, the resistor R3 and the resistor R4 are used for high level voltage division in the circuit, so that the high and low levels of the triode Q1 to the triode Q2 are stable, the c electrode of the triode Q2 is connected with the input end of the internal module 2, the c electrode of the triode Q1 is connected with a direct current power supply DC through a resistor R2, the direct current power supply DC provides a high level signal for the triode Q2 through the resistor R2, the resistor R2 and the direct current power supply DC are connected with the c electrode of the triode Q2 in sequence through a diode Z1 and a resistor R5, when the external module 1 uses the internal direct current power supply DC as the pull-up, the one-way conductivity of the diode Z1 is used to prevent the circuit from being connected in series, the resistor R5 is mainly used for current limiting in the circuit, reduces power consumption, prevents the internal direct current power supply DC from damaging the input end of the internal module 2, and further ensures that the electric signals of the external circuit are effectively transmitted to the internal module 2, so that the influence of static electricity is avoided.

[0032] The output end of the internal module 2 is connected with a resistor R10, the resistor R10 is connected with the b electrode of a triode Q4 and a resistor R12 respectively, the resistor R10 and the resistor R12 are used for high level voltage division in the circuit, so that the high and low levels of the output end of the internal module 2 to the triode Q4 are stable, the resistor R12 is connected with the e electrode of the triode Q4, the c electrode of the triode Q4 is connected with the b electrode of a triode Q3 through a resistor R8, the resistor R8 is connected with the ground through a resistor R7 between the resistor R8 and the triode Q3, the resistor R7 and the resistor R8 are used for high level voltage division in the circuit, so that the high and low levels of the triode Q4 to the triode Q3 are stable, the c electrode of the triode Q3 is connected with the input end of the external module 1, the c electrode of the triode Q4 is connected with a direct current power supply DC through a resistor R9, the direct current power supply DC provides a high level signal for the triode Q3 through the resistor R9, the direct current power supply DC is connected with the c electrode of the triode Q3 through a resistor R6, so as to ensure that the electric signal of the internal circuit is effectively transmitted to the external module 1, and the influence of static electricity is avoided. The electric signal input and output of the present application are converted through two-stage triodes, the effective propagation of the original signal is realized, the communication signal is stable and safe, and the problem of communication failure of different level module circuits is avoided.

[0033] The specific working process is as follows:

[0034] When the external module 1 receives a high level, the triode Q1 is driven after voltage division of the resistor R1 and the resistor R11, the b electrode of the triode Q1 becomes a high level, the c electrode and the e electrode of the triode Q1 are turned on, the c electrode of the triode Q1 is a low level 0V, at this time, the b electrode of the triode Q2 changes to 0V, the triode Q2 enters the cut-off state, the c electrode of the triode Q2 turns to a high level, and the input end of the internal module 2 receives the high level signal of the output end of the external module 1;

[0035] When the external module 1 receives a low level, the b electrode of the triode Q1 becomes a low level after voltage division of the resistor R1 and the resistor R11, the triode Q1 enters the cut-off state, the c electrode and the e electrode of the triode Q1 are disconnected, the c electrode of the triode Q1 becomes a high level, at this time, the b electrode of the triode Q2 becomes a high level, the c electrode and the e electrode of the triode Q2 are turned on, the c electrode of the triode Q2 changes to 0V, and the input end of the internal module 2 receives the low level signal of the output end of the external module 1;

[0036] When the internal module 2 receives a high level, the b electrode of the triode Q4 becomes a high level after voltage division of the resistor R10 and the resistor R12, the c electrode and the e electrode of the triode Q4 are turned on, the c electrode of the triode Q4 is a low level 0V, at this time, the b electrode of the triode Q3 changes to 0V, the triode Q3 enters the cut-off state, the c electrode of the triode Q3 turns to a high level, and the input end of the external module 1 receives the high level signal of the output end of the internal module 2;

[0037] When the internal module 2 receives a low level, after voltage division by the resistor R10 and the resistor R12, the b electrode of the triode Q4 becomes low level, the triode Q4 enters the off state, the c electrode and the e electrode of the triode Q4 are disconnected, the c electrode of the triode Q4 becomes high level, at this time, the b electrode of the triode Q4 becomes high, the c electrode and the e electrode of the triode Q3 are connected, the c electrode of the triode Q3 changes to 0V, and the input end of the external module 1 receives the low level signal of the output end of the internal module 2.

[0038] Embodiment one:

[0039] Referring to Figure 1 The application discloses a UART communication isolation level conversion circuit, which comprises an external module 1 and an internal module 2.

[0040] The output end of the external module 1 is connected with a resistor R1, the resistor R1 is connected with the b electrode of a triode Q1 and a resistor R11 respectively, the resistor R11 is connected with the e electrode of the triode Q1, the c electrode of the triode Q1 is connected with the b electrode of a triode Q2 through a resistor R3, the resistor R3 is grounded through a resistor R4 between the triode Q2, the c electrode of the triode Q2 is connected with the input end of the internal module 2, the c electrode of Q1 is connected with a direct current power supply DC through a resistor R2, and the resistor R2 is connected with the c electrode of the triode Q2 in sequence through a diode Z1 and a resistor R5 between the direct current power supply DC.

[0041] The output end of the internal module 2 is connected with a resistor R10, the resistor R10 is connected with the b electrode of a triode Q4 and a resistor R12 respectively, the resistor R12 is connected with the e electrode of the triode Q4, the c electrode of the triode Q4 is connected with the b electrode of a triode Q3 through a resistor R8, the resistor R8 is grounded through a resistor R7 between the triode Q3, the c electrode of the triode Q3 is connected with the input end of the external module 1, the c electrode of Q4 is connected with the direct current power supply DC through a resistor R9, and the direct current power supply DC is connected with the c electrode of the triode Q3 through a resistor R6.

[0042] The triode is selected according to the anti-static level, and the general plastic-sealed triode meets the discharge requirement of 8KV direct contact of vehicle-mounted, thereby saving the cost of increasing an ESD tube.

[0043] Preferably, the e electrodes of the triode Q1, the triode Q2, the triode Q3 and the triode Q4 are grounded.

[0044] Preferably, the output end and the input end of the external module 1 are both universal asynchronous receiver-transmitter, specifically, UART_TX_MCU.

[0045] Preferably, the output end and the input end of the internal module 2 are both universal asynchronous receiver-transmitter, specifically, UART_TX_OUT.

[0046] Preferably, the resistor R4 is connected with a first capacitor in parallel.

[0047] Preferably, a first capacitor is connected in parallel with resistor R7.

[0048] Preferably, a second capacitor is connected in parallel with resistor R11.

[0049] Preferably, a second capacitor is connected in parallel with resistor R12.

[0050] Preferably, the size of the first capacitor is 101, or 100pF.

[0051] Preferably, the size of the second capacitor is 102, or 1NF.

[0052] Example 2:

[0053] See Figure 1 This embodiment discloses a UART communication isolation level conversion circuit, including signal input and output, resistor voltage divider, driving a first-stage transistor switch, and a second-stage transistor switch to switch positive and negative levels. It can select any power supply pull-up to keep the level from cross-current and share the same power supply as the corresponding module circuit.

[0054] Furthermore, in the signal conversion process, the three-bit TX signal of external module 1 outputs a high level from one module end. After being divided by resistors R1 and R11, it drives Q1. When the ce terminal of Q1 is turned on, the collector of Q2 is at a low level. When the ce terminal of Q2 is turned off, the collector of Q2 is at a high level. The circuit restores the TX signal to a high level. The pull-up resistor R5 can be connected to the receiving end without affecting the operation of other modules.

[0055] Another set of RX signals sends a high-level signal from internal module 2. After being divided by resistors R10 and R12, it drives the NPN transistor Q4. When Q4 is turned on, the voltage at the collector is 0. At this time, the base of Q3 is at a low level. When Q3 is turned off, the collector is at a high level, and the circuit restores the RX signal to a high level.

[0056] When a signal is switched to a low level, all switching levels are reversed.

[0057] To address the signal anomalies caused by different communication levels between different module circuits, this invention provides a UART communication isolation level conversion circuit to replace the level conversion chip and solve the problem of communication failure between module circuits with different levels.

[0058] Example 3:

[0059] like Figure 1 As shown, the UART communication isolation level conversion circuit of the present invention includes a resistor voltage divider, a transistor switch, and a diode unidirectional conductivity circuit.

[0060] The circuit is pulled up by DC 3.3V, if the internal module 2 power voltage is different from the external module 1 power voltage, the diode Z1 power needs to be connected to the power on the internal module 2; the UART communication port selects the common beta value of the triode BC846B which is about 200 and the frequency is 100MHz.

[0061] Preferably, the resistance R1, the resistance R11, the resistance R3, the resistance R4, the resistance R7, the resistance R8, the resistance R10 and the resistance R12 are equal to 10KΩ, and the resistance R2, the resistance R5, the resistance R6 and the resistance R9 are equal to 4.7KΩ.

[0062] The external module 1 TX sends the high level signal of DC 3.3V, which is divided by the resistance R1 and the resistance R11, so that the b pole of the triode Q1 becomes the high level 0.7V, the c pole and the e pole of the triode Q1 are conducted, and the c pole is converted from the high level 3.3V to the low level 0V; at this time, the b pole of the triode Q2 is changed from the high level DC 0.7V to 0V, the triode Q2 enters the cut-off state, the c pole is changed from the low level 0V to the high level, and the high level signal of the internal module 2 end is received by the external module 1 end; if the external module 1 end continues to send the low level signal, the b pole of the first stage triode Q1 is low, the triode Q1 is cut off, the c pole and the e pole are disconnected, the voltage of the c pole is changed from the low level 0V to the high level 3.3V, the b pole of the triode Q2 is also converted to the high level 3.3V at this time, the triode Q2 is conducted, the voltage of the c pole is 0V, and the low level signal of the internal module 2 end is received by the external module 1 end; in this way, the high and low level signals can be effectively and continuously converted.

[0063] The internal module 2 sends the high level 3.3V signal to the external module 1, which is divided by the resistance R10 and the resistance R12, so that the b pole of the triode Q4 becomes the high level 0.7V, the c pole and the e pole of the triode Q4 are conducted, and the c pole is converted from the high level 3.3V to the low level 0V; at this time, the b pole of the triode Q3 is changed from the high level DC 0.7V to 0V, the triode Q3 enters the cut-off state, the c pole is changed from the low level 0V to the high level 3.3V, and the high level signal of the internal module 2 end is received by the external module 1 end; if the internal module 2 end continues to send the low level signal, the b pole of the first stage triode Q4 is low, the triode Q4 is cut off, the c pole and the e pole are disconnected, the voltage of the c pole is changed from the low level 0V to the high level 3.3V, the b pole of the triode Q3 is also converted to the high level 3.3V at this time, the triode Q3 is conducted, the voltage of the c pole is 0V, and the low level signal of the internal module 2 end is received by the external module 1 end; in this way, the high and low level signals can be effectively and continuously converted.

[0064] In summary, the UART port conversion circuit of the example of the application can ensure that the communication signal is stable and safe.

[0065] The above merely illustrates the technical idea of the present application, and cannot limit the protection scope of the present application. Any modification made according to the technical idea of the present application on the basis of the technical scheme falls within the protection scope of the present application.

Claims

1. A UART communication isolation level conversion circuit, characterized in that, The external module and the internal module are included. The output end of the external module is connected with a resistor R1, the resistor R1 is connected with the b electrode of a triode Q1 and a resistor R11 respectively, the resistor R11 is connected with the e electrode of the triode Q1, the c electrode of the triode Q1 is connected with the b electrode of a triode Q2 through a resistor R3, the resistor R3 is grounded through a resistor R4, the c electrode of the triode Q2 is connected with the input end of the internal module, the c electrode of Q1 is connected with a direct current power supply DC through a resistor R2, the resistor R2 is connected with the c electrode of the triode Q2 through a diode Z1 and a resistor R5 in sequence; The output end of the internal module is connected with a resistor R10, the resistor R10 is connected with the b electrode of a triode Q4 and a resistor R12 respectively, the resistor R12 is connected with the e electrode of the triode Q4, the c electrode of the triode Q4 is connected with the b electrode of a triode Q3 through a resistor R8, the resistor R8 is grounded through a resistor R7, the c electrode of the triode Q3 is connected with the input end of the external module, the c electrode of Q4 is connected with the direct current power supply DC through a resistor R9, the direct current power supply DC is connected with the c electrode of the triode Q3 through a resistor R6; The output end and the input end of the external module are both universal asynchronous receiver-transmitters. The output end and the input end of the internal module are both universal asynchronous receiver-transmitters.

2. The UART communication isolation level conversion circuit according to claim 1, characterized in that, The e electrodes of the triode Q1, the triode Q2, the triode Q3 and the triode Q4 are all grounded.

3. The UART communication isolation level conversion circuit according to claim 1, characterized in that, The resistor R4 is connected with a first capacitor in parallel.

4. The UART communication isolation level conversion circuit according to claim 1, characterized in that, The resistor R7 is connected with a first capacitor in parallel.

5. The UART communication isolation level conversion circuit according to claim 1, characterized in that, The resistor R11 is connected with a second capacitor in parallel.

6. The UART communication isolation level conversion circuit according to claim 1, characterized in that, The resistor R12 is connected with a second capacitor in parallel.

7. The UART communication isolation level conversion circuit according to any one of claims 3 to 4, characterized in that, The first capacitor is 100PF.

8. The UART communication isolation level conversion circuit according to any one of claims 5 to 6, characterized in that, The second capacitor is 1NF.

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