CN111427825A - Serial port level conversion circuit - Google Patents
Serial port level conversion circuit Download PDFInfo
- Publication number
- CN111427825A CN111427825A CN202010287990.7A CN202010287990A CN111427825A CN 111427825 A CN111427825 A CN 111427825A CN 202010287990 A CN202010287990 A CN 202010287990A CN 111427825 A CN111427825 A CN 111427825A
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- Prior art keywords
- serial port
- module
- resistor
- voltage
- port module
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F13/00—Interconnection of, or transfer of information or other signals between, memories, input/output devices or central processing units
- G06F13/38—Information transfer, e.g. on bus
- G06F13/40—Bus structure
- G06F13/4063—Device-to-bus coupling
- G06F13/4068—Electrical coupling
- G06F13/4072—Drivers or receivers
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F13/00—Interconnection of, or transfer of information or other signals between, memories, input/output devices or central processing units
- G06F13/38—Information transfer, e.g. on bus
- G06F13/42—Bus transfer protocol, e.g. handshake; Synchronisation
- G06F13/4282—Bus transfer protocol, e.g. handshake; Synchronisation on a serial bus, e.g. I2C bus, SPI bus
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K19/00—Logic circuits, i.e. having at least two inputs acting on one output; Inverting circuits
- H03K19/0175—Coupling arrangements; Interface arrangements
- H03K19/017509—Interface arrangements
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F2213/00—Indexing scheme relating to interconnection of, or transfer of information or other signals between, memories, input/output devices or central processing units
- G06F2213/0002—Serial port, e.g. RS232C
Abstract
The invention discloses a serial port level conversion circuit, comprising: the device comprises a first serial port module, a second serial port module, a voltage reduction module and a voltage boosting module; one end of the boosting module is connected with the receiving end of the first serial port module, and the other end of the boosting module is connected with the transmitting end of the second serial port module; the boosting module comprises a first resistor, a second resistor, a third resistor, an MOS (metal oxide semiconductor) tube and a triode; one end of the voltage reduction module is connected with the transmitting end of the first serial port module, and the other end of the voltage reduction module is connected with the receiving end of the second serial port module; the voltage reduction module comprises a fourth resistor and a fifth resistor; the serial port level conversion circuit disclosed by the invention simplifies the circuit and improves the stability and response efficiency of serial port communication by reducing the use of filter elements.
Description
Technical Field
The invention relates to the technical field of serial port communication, in particular to a serial port level conversion circuit.
Background
At present, in circuit design, units powered by different voltages exist, so that serial ports can be used for data transmission among the units, an existing serial port level conversion circuit is often too complex, some electronic elements and even special chips need to be added for level conversion, for example, some transistors, capacitors and other filter elements are adopted, but the circuit cost is high, phase shift and time sequence influence are easily caused, and serial port communication is unstable and response efficiency is low.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a serial port level conversion circuit, which improves the stability and response efficiency of serial port communication.
In order to achieve the above object, an embodiment of the present invention provides a serial port level shift circuit, including: the device comprises a first serial port module, a second serial port module, a voltage reduction module and a voltage boosting module;
one end of the boosting module is connected with the receiving end of the first serial port module, and the other end of the boosting module is connected with the transmitting end of the second serial port module; the boosting module comprises a first resistor, a second resistor, a third resistor, an MOS (metal oxide semiconductor) tube and a triode;
one end of the first resistor is connected with the transmitting end of the first serial port module, and the other end of the first resistor is connected with the base electrode of the triode; the emitting electrode of the triode is grounded, and the collector electrode of the triode is simultaneously connected with one end of the second resistor and one end of the third resistor; the source electrode of the MOS tube is connected with the other end of the second resistor, the grid electrode of the MOS tube is connected with the other end of the third resistor, and the drain electrode of the MOS tube is connected with the receiving end of the first serial port module;
one end of the voltage reduction module is connected with the transmitting end of the first serial port module, and the other end of the voltage reduction module is connected with the receiving end of the second serial port module; the voltage reduction module comprises a fourth resistor and a fifth resistor;
one end of the fifth resistor is connected with the transmitting end of the first serial port module, and the other end of the fifth resistor is connected with the receiving end of the second serial port module; one end of the fourth resistor is grounded, and the other end of the fourth resistor is connected with the receiving end of the second serial port module; and the resistance value of the fourth resistor is greater than or equal to five times of the impedance of the receiving end of the second serial port module.
Further, the fourth resistance and the fifth resistance satisfy the following relationship: r5 ═ R4/((VCC1/VCC2) -1); wherein, R4 is a fourth resistor, R5 is a fifth resistor, VCC1 is a first serial module access voltage, and VCC2 is a second serial module access voltage.
Furthermore, the serial port level conversion circuit further comprises a sixth resistor, one end of the sixth resistor is grounded, and the other end of the sixth resistor is connected with the drain electrode of the MOS transistor.
Furthermore, the access voltage of the first serial port module is greater than that of the second serial port module.
Furthermore, the access voltage of the second resistor is the same as that of the first serial module.
Further, the MOS transistor is a PMOS transistor, and the triode is an NPN type triode.
Further, the second serial port module is one of an MCU module, an NB-IOT module and a ZIGBEE module.
Further, the access voltage of the second serial port module is less than or equal to 3.3V.
Furthermore, the first serial port module is one of an MCU module, a sensor module, an RS232 module and an RS485 module.
Furthermore, the access voltage of the first serial module is more than or equal to 5V.
Compared with the prior art, the serial port level conversion circuit provided by the embodiment of the invention simplifies the circuit, reduces the production cost and improves the communication stability and response efficiency of the serial port module by reducing the use of filtering elements such as transistors and capacitors.
Drawings
Fig. 1 is a circuit diagram of a serial port level conversion circuit provided by the invention.
Fig. 2 is a module connection diagram of the serial port level shift circuit provided by the invention.
Detailed Description
The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention. All other embodiments obtained by a person of ordinary skill in the art without any inventive step based on the embodiments of the present invention shall fall within the scope of protection of the present invention.
Referring to fig. 1, a circuit diagram of a serial port level shift circuit according to an embodiment of the present invention includes: the device comprises a first serial port module, a second serial port module, a voltage reduction module and a voltage boosting module;
one end of the boosting module is connected with the receiving end of the first serial port module, and the other end of the boosting module is connected with the transmitting end of the second serial port module; the boosting module comprises a first resistor, a second resistor, a third resistor, an MOS (metal oxide semiconductor) tube and a triode;
one end of the first resistor is connected with the transmitting end of the first serial port module, and the other end of the first resistor is connected with the base electrode of the triode; the emitting electrode of the triode is grounded, and the collector electrode of the triode is simultaneously connected with one end of the second resistor and one end of the third resistor; the source electrode of the MOS tube is connected with the other end of the second resistor, the grid electrode of the MOS tube is connected with the other end of the third resistor, and the drain electrode of the MOS tube is connected with the receiving end of the first serial port module;
one end of the voltage reduction module is connected with the transmitting end of the first serial port module, and the other end of the voltage reduction module is connected with the receiving end of the second serial port module; the voltage reduction module comprises a fourth resistor and a fifth resistor;
one end of the fifth resistor is connected with the transmitting end of the first serial port module, and the other end of the fifth resistor is connected with the receiving end of the second serial port module; one end of the fourth resistor is grounded, and the other end of the fourth resistor is connected with the receiving end of the second serial port module; and the resistance value of the fourth resistor is greater than or equal to five times of the impedance of the receiving end of the second serial port module.
In this embodiment, a serial port level shift circuit is provided, where the first serial port module access voltage and the second serial port module access voltage are VCC1 and VCC2, respectively, and VCC1 is greater than VCC 2; because VCC1 is not equal to VCC2, the transmitting and receiving ends of two serial units cannot be directly connected, and therefore a level conversion circuit switching as shown in fig. 1 is needed, wherein R4 and R5 constitute a set of voltage reduction circuits, a serial module with high voltage power supply transmits data to a serial module with low voltage power supply, specifically, a transmitting pin of a high voltage power supply unit is used for reducing voltage through resistors R4 and R5, and is directly converted into voltage suitable for a receiving pin of a low voltage unit, wherein R4 and R5 are selected such that R4 must be more than 5 times larger than the impedance of the receiving end of the low voltage unit.
R1, R2, R3, Q1 and Q2 form a group of booster circuit and pulse control circuit, realize the serial port module of low-voltage power supply transmits data to the serial port module of high-voltage power supply, when the serial port transmitting terminal of low-voltage power supply is the high level, the magnitude of this high level is VCC2 makes NPN type triode Q2 turn on through R1, the grid of PMOS pipe Q1 is pulled down because of Q2 switches on at this moment, make Q1 also switch on, namely VCC1 has received the serial port receiving terminal of the high-voltage power supply unit directly, namely this receiving terminal is VCC1 of the high level too, and when the serial port transmitting terminal of the low-voltage power supply is the low level, this low level makes NPN type triode Q2 cut off through R1, so the serial port receiving terminal of the high-voltage power supply unit is pulled into the low level directly by R6. Due to the fact that Q1 and Q2 are conducted and cut off quickly, signals transmitted by a low-voltage serial port can be converted into signals received by a high-voltage serial port without delay. In the boosting module, a serial port module which can bring specific numerical values to realize low-voltage power supply transmits data to a serial port module which supplies power to high voltage; for example, the following methods are adopted: r1 equals to 1K, R2 equals to 10K, R3 equals to 470 omega, a PMOS tube Q1 with the model of AO3401 and a triode Q2 with the model of SS8050 can realize that a serial port with 3.3V sends data to a serial port with more than 5V.
In an embodiment of the serial port level shifter circuit provided in the present invention, the fourth resistor and the fifth resistor satisfy the following relationship: r5 ═ R4/((VCC1/VCC2) -1); wherein, R4 is a fourth resistor, R5 is a fifth resistor, VCC1 is a first serial module access voltage, and VCC2 is a second serial module access voltage.
In this embodiment, after the resistance of R4 is determined, R5 ═ R4/((VCC1/VCC2) -1); for example, the resistors R4-10K and R5-5.1K are used, so that the serial port circuit supplied with 5V power can transmit data to the serial port supplied with 3.3V power, and signals transmitted by the high-voltage serial port can be simply and stably converted into low-voltage serial port receiving signals without delay.
In an embodiment of the present invention, the serial port level shifter circuit further includes a sixth resistor, one end of the sixth resistor is grounded, and the other end of the sixth resistor is connected to the drain of the MOS transistor.
In an embodiment of the present invention, an access voltage of the first serial module is greater than an access voltage of the second serial module.
In an embodiment of the serial port level shifter circuit provided in the present invention, an access voltage of the second resistor is the same as an access voltage of the first serial port module.
In an embodiment of the serial port level shift circuit provided in the present invention, the MOS transistor is a PMOS transistor, and the triode is an NPN-type triode.
In the present embodiment, the MOS transistor is a PMOS transistor, which can be divided into two categories, N-channel and P-channel, the P-channel MOS transistor has low hole mobility, so that the transconductance of the PMOS transistor is smaller than that of the N-channel MOS transistor under the condition that the geometric size of the MOS transistor and the absolute value of the operating voltage are equal.
In an embodiment of the serial port level shift circuit provided in the present invention, the second serial port module is one of an MCU module, an NB-IOT module, and a ZIGBEE module.
In this embodiment, the MCU module, i.e., the micro control Unit, also called a Single chip microcomputer (CPU) or a Single chip microcomputer, is a chip-level computer formed by appropriately reducing the frequency and specification of a Central Processing Unit (CPU) and integrating peripheral interfaces such as a memory (memory), a counter (Timer), a USB, an a/D converter, a UART, and P L C, DMA, and even a L CD driver circuit on a Single chip, and can be used for different applications, such as mobile phones, PC peripherals, remote controllers, automotive electronics, industrial step motors, and robot arm controls, and the like, and can see the shadow of the MCU.
In an embodiment of the serial port level shifter circuit provided in the present invention, an access voltage of the second serial port module is less than or equal to 3.3V.
In an embodiment of the serial port level conversion circuit provided by the invention, the first serial port module is one of an MCU, a sensor module, an RS232 module and an RS485 module.
In this embodiment, the RS232/RS 485-to-ethernet module is a device for implementing transparent transmission of RS232 or RS485 interface data of a network data packet, and the sensor module can sense measured information and convert the sensed information into an electrical signal or other information in a required form according to a certain rule for output, so as to meet requirements of information transmission, processing, storage, display, recording, control, and the like. The sensor is characterized in that: miniaturization, digitalization, intellectualization, multifunction, systematization and networking. The method is the first link for realizing automatic detection and automatic control and can be divided into a thermosensitive element, a photosensitive element, a gas sensitive element, a force sensitive element, a magnetic sensitive element, a humidity sensitive element, a sound sensitive element, a radioactive ray sensitive element, a color sensitive element, a taste sensitive element and the like.
In an embodiment of the serial port level shifter circuit provided in the present invention, an access voltage of the first serial port module is greater than or equal to 5V.
While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.
Claims (10)
1. A serial port level shifter circuit, comprising: the device comprises a first serial port module, a second serial port module, a voltage reduction module and a voltage boosting module;
one end of the boosting module is connected with the receiving end of the first serial port module, and the other end of the boosting module is connected with the transmitting end of the second serial port module; the boosting module comprises a first resistor, a second resistor, a third resistor, an MOS (metal oxide semiconductor) tube and a triode;
one end of the first resistor is connected with the transmitting end of the first serial port module, and the other end of the first resistor is connected with the base electrode of the triode; the emitting electrode of the triode is grounded, and the collector electrode of the triode is simultaneously connected with one end of the second resistor and one end of the third resistor; the source electrode of the MOS tube is connected with the other end of the second resistor, the grid electrode of the MOS tube is connected with the other end of the third resistor, and the drain electrode of the MOS tube is connected with the receiving end of the first serial port module;
one end of the voltage reduction module is connected with the transmitting end of the first serial port module, and the other end of the voltage reduction module is connected with the receiving end of the second serial port module; the voltage reduction module comprises a fourth resistor and a fifth resistor;
one end of the fifth resistor is connected with the transmitting end of the first serial port module, and the other end of the fifth resistor is connected with the receiving end of the second serial port module; one end of the fourth resistor is grounded, and the other end of the fourth resistor is connected with the receiving end of the second serial port module; and the resistance value of the fourth resistor is greater than or equal to five times of the impedance of the receiving end of the second serial port module.
2. The serial port level shift circuit according to claim 1, wherein the fourth resistor and the fifth resistor satisfy the following relationship: r5 ═ R4/((VCC1/VCC2) -1); wherein, R4 is a fourth resistor, R5 is a fifth resistor, VCC1 is a first serial module access voltage, and VCC2 is a second serial module access voltage.
3. The serial port level shift circuit according to claim 1, further comprising a sixth resistor, wherein one end of the sixth resistor is grounded, and the other end of the sixth resistor is connected to the drain of the MOS transistor.
4. The serial port level shifter circuit of claim 1, wherein the first serial port module access voltage is greater than the second serial port module access voltage.
5. The serial port level shifter circuit of claim 1, wherein the second resistor access voltage is the same as the first serial port module access voltage.
6. The serial port level shifter circuit according to claim 1, wherein the MOS transistor is a PMOS transistor, and the transistor is an NPN transistor.
7. The serial port level shift circuit of claim 1, wherein the second serial port module is one of an MCU module, an NB-IOT module, and a ZIGBEE module.
8. The serial port level shift circuit according to claim 1, wherein the second serial port module access voltage is less than or equal to 3.3V.
9. The serial port level shift circuit according to claim 1, wherein the first serial port module is one of an MCU module, a sensor module, an RS232 module, and an RS485 module.
10. The serial port level shifter circuit of claim 1, wherein the first serial port module access voltage is greater than or equal to 5V.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010287990.7A CN111427825A (en) | 2020-04-13 | 2020-04-13 | Serial port level conversion circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010287990.7A CN111427825A (en) | 2020-04-13 | 2020-04-13 | Serial port level conversion circuit |
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| Publication Number | Publication Date |
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| CN111427825A true CN111427825A (en) | 2020-07-17 |
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| CN202010287990.7A Pending CN111427825A (en) | 2020-04-13 | 2020-04-13 | Serial port level conversion circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114443535A (en) * | 2022-01-19 | 2022-05-06 | 苏州冠德能源科技有限公司 | Serial data communication port conversion circuit and conversion device |
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2020
- 2020-04-13 CN CN202010287990.7A patent/CN111427825A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114443535A (en) * | 2022-01-19 | 2022-05-06 | 苏州冠德能源科技有限公司 | Serial data communication port conversion circuit and conversion device |
| CN114443535B (en) * | 2022-01-19 | 2024-01-30 | 苏州冠德能源科技有限公司 | Serial data communication port conversion circuit and conversion device |
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