CN109547010A - Passive isolated form RS232 serial communication circuit - Google Patents
Passive isolated form RS232 serial communication circuit Download PDFInfo
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- CN109547010A CN109547010A CN201910058153.4A CN201910058153A CN109547010A CN 109547010 A CN109547010 A CN 109547010A CN 201910058153 A CN201910058153 A CN 201910058153A CN 109547010 A CN109547010 A CN 109547010A
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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
- H03K19/0185—Coupling arrangements; Interface arrangements using field effect transistors only
- H03K19/018507—Interface arrangements
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Abstract
The invention discloses a kind of passive isolated form RS232 serial communication circuits, turn TTL module, TTL signal isolation module, TTL RS 232 module including RS232, the RS232 turns TTL module for the first RS232 level signal to be converted to the first Transistor-Transistor Logic level signal or the first Transistor-Transistor Logic level signal is converted to the first RS232 level signal；The TTL signal isolation module and the RS232 turn the electric connection of TTL module, the TTL signal isolation module is used for the first Transistor-Transistor Logic level signal isolation, and the second Transistor-Transistor Logic level signal is exported, or by the second Transistor-Transistor Logic level signal isolation and be converted into the first Transistor-Transistor Logic level signal；The TTL RS 232 module and the TTL signal isolation module are electrically connected, and the TTL RS 232 module is for being converted to the 2nd RS232 level signal for the second Transistor-Transistor Logic level signal or the 2nd RS232 level signal being converted to the second Transistor-Transistor Logic level signal.So that both ends communication signal be it is independent, do not interfere with each other, enhance RS232 communication protocol signal anti-interference.
Description
Technical field
The present invention relates to electronic communication technology field more particularly to a kind of passive isolated form RS232 serial communication circuits.
Background technique
In Electronic Design industry, there are many communication interfaces of multiplicity, such as USB, JTAG, I2C, SPI, RS232 and
The interfaces such as RS485, RS232 interface are also known as DB9 interface, are present one of mainstream serial communication interface, agreement RS232
Agreement is one of the end PC, equipment end serial communication or test port important interface, and especially industrially, RS232 interface is common
Come serial communication and equipment detection.Since RS232 interface standard agreement occurs very early, there is following disadvantage:
1, the signal level value of interface is higher, and RS232 interface agreement uses antilogical: logic " 0 " :+3~+15V, logic "
1 ": -3~-15V.
2, interface constitutes the transmission form on total ground using a signal wire and a signal line of return, this to transmit altogether
It is easy to produce common mode interference, so noise immunity is weak.
Summary of the invention
The present invention is directed to solve at least some of the technical problems in related technologies.For this purpose, of the invention
One purpose is to propose a kind of passive isolated form RS232 serial communication circuit.
To achieve the above object, passive isolated form RS232 serial communication circuit according to an embodiment of the present invention, it is described passive
Isolated form RS232 serial communication circuit includes:
RS232 turns TTL module, and the RS232 turns TTL module for the first RS232 level signal to be converted to the first TTL
First Transistor-Transistor Logic level signal is converted to the first RS232 level signal by level signal；
TTL signal isolation module, the TTL signal isolation module and the RS232 turn the electric connection of TTL module, described
TTL signal isolation module is used for the first Transistor-Transistor Logic level signal isolation, and exports the second Transistor-Transistor Logic level signal, or by second
Transistor-Transistor Logic level signal isolation is simultaneously converted into the first Transistor-Transistor Logic level signal；
TTL RS 232 module, the TTL RS 232 module and the TTL signal isolation module are electrically connected, described
TTL RS 232 module is used to the second Transistor-Transistor Logic level signal be converted to the 2nd RS232 level signal or by described second
RS232 level signal is converted to the second Transistor-Transistor Logic level signal.
Further, according to one embodiment of present invention, further includes: power supply module, the power supply module
Turn TTL module, TTL signal isolation module and TTL RS 232 module with the RS232 respectively to connect, for being the RS232
Turn TTL module, TTL signal isolation module and TTL RS 232 module and power supply is provided.
Further, according to one embodiment of present invention, the power supply module includes the first power supply module
With the second power supply module, first power supply module turns TTL module with the RS232 and the TTL signal isolation module is connect,
For at least output signal in the first RS232 level signal to be converted to the first power supply, and turn for the RS232
The power supply of first Transistor-Transistor Logic level signal end of TTL module for power supply and the TTL signal isolation module；
Second power supply module is connect with the TTL RS 232 module and the TTL signal isolation module, and being used for will
An at least output signal in the 2nd RS232 level signal converts second source, and supplies for the TTL RS 232 module
Second Transistor-Transistor Logic level signal end of the electric and described TTL signal isolation module is powered.
Further, according to one embodiment of present invention, first power supply module includes: diode D11, two
Pole pipe D12, diode D13, diode D14, resistance R7 and capacitor C1, the diode D11, diode D12, diode D13,
Diode D14 forms the first rectification circuit, and first rectification circuit input end turns TTL module with the RS232 and connect, described
First rectification circuit output end is connect with one end of the resistance R7, one end of the other end of the resistance R7 and the capacitor C1
Connection, the other end of the capacitor C1 are connect with second with reference to ground VSS, and described one end of the capacitor C1 and the RS232 turn
The signal-powered end connection of first Transistor-Transistor Logic level of TTL module and the TTL signal isolation module.
Further, according to one embodiment of present invention, first power supply module includes: diode D5, electricity
The anode of resistance R60 and resistance R6, the diode D5 turn TTL module with the RS232 and connect, the cathode of the diode D5 and
One end of the resistance R60 connects, and the other end of the resistance R60 is connect with one end of the resistance R6, the resistance R6's
The other end is connect with first with reference to ground LGND, and described one end of the resistance R6 also turns TTL module and described with the RS232
The signal-powered end connection of first Transistor-Transistor Logic level of TTL signal isolation module.
Further, according to one embodiment of present invention, the second source power supply module includes: diode D6, two
Pole pipe D7, diode D9, diode D10, resistance R63 and capacitor C24, the diode D6, diode D7, diode D9, two
Pole pipe D10 forms the second rectification circuit, and second rectification circuit input end turns TTL module with the RS232 and connect, and described the
Two rectification circuit output ends are connect with one end of the resistance R63, and the one of the other end of the resistance R63 and the capacitor C24
End connection, the other end of the capacitor C24 with second with reference to VSS connect, described one end of the capacitor C24 also with it is described
The signal-powered end connection of second Transistor-Transistor Logic level of TTL RS 232 module and the TTL signal isolation module.
Further, according to one embodiment of present invention, it includes: that the first transmission signal turns that the RS232, which turns TTL module,
It changes the mold block and first and receives signal conversion module；
The first transmission signal conversion module includes triode Q1, resistance R57, resistance R56, capacitor C5 and diode
D4, one end of the resistance R57 are connect with the first transmitting terminal of the TTL signal isolation module, the other end of the resistance R57
It is connect with the base stage of the triode Q1, the collector of the triode Q1 is connect with one end of the resistance R56, the resistance
The other end of R56 is connect with one end of the capacitor C5, and the other end of the capacitor C5 is connect with first with reference to ground LGDN, described
The emitter of triode Q1 is connect with the first power supply, the collector of the triode Q1 also with the first RS232 level signal
Receiving end connection, the anode of the diode D4 connect with described one end of the capacitor C5, the cathode of the diode D4
It is connect with the transmitting terminal of the first RS232 level signal；
The first reception signal conversion module includes triode Q5, resistance R58 and resistance R59, and the one of the resistance R58
End is connect with the transmitting terminal of the first RS232 level signal, and the base stage of triode Q5 described in the other end of the resistance R58 connects
It connects, the emitter of the triode Q5 is connect with described first with reference to ground LGDN, the collector and the electricity of the triode Q5
One end connection of R59 is hindered, the other end of the resistance R59 is connect with first power supply, and the collector of the triode Q5 is also
It is connect with the first receiving end of the TTL signal isolation module.
It further, according to one embodiment of present invention, further include zener diode D1, the zener diode D1's
Anode is connect with the base stage of the triode Q5, and the cathode of the zener diode D1 is connect with described first with reference to ground LGDN.
Further, according to one embodiment of present invention, the TTL signal isolation module includes:
The collector of first optocoupler U15, the first optocoupler U15 is connect by resistance R62 with the first power supply, and described first
The emitter of optocoupler U15 is connect with the RS232 transmission signal end for turning TTL module, the cathode of the first optocoupler U15 and
Two connect with reference to ground VSS connection, the anode of the first optocoupler U15 with the signal sending end of the TTL RS 232 module；
The collector of second optocoupler U18, the second optocoupler U18 is connect by resistance R5 with second source, and described second
The emitter of optocoupler U18 is connect with the reception signal end of the TTL RS 232 module, the cathode of the second optocoupler U18 and
One connect with reference to ground LGND connection, the anode of the second optocoupler U18 with the RS232 signal receiving end for turning TTL module.
Further, according to one embodiment of present invention, the TTL RS 232 module includes: that the second transmission signal turns
It changes the mold block and second and receives signal conversion module；
The second transmission signal conversion module includes triode Q2, resistance R3 and resistance R2, one end of the resistance R3
It is connect with the receiving end of the 2nd RS232 level signal, the base stage connection of triode Q2 described in the other end of the resistance R3,
The emitter of the triode Q5 is connect with described second with reference to ground VSS, the collector of the triode Q2 and the resistance R2
One end connection, the other end of the resistance R2 connect with second source, the collector of the triode Q2 also with TTL letter
The second transmitting terminal connection of number isolation module；
The second reception signal conversion module includes triode Q3, resistance R1, resistance R4, capacitor C2 and diode D8,
One end of the resistance R1 is connect with the second receiving end of the TTL signal isolation module, the other end of the resistance R1 and institute
The base stage connection of triode Q3 is stated, the collector of the triode Q3 is connect with one end of the resistance R4, the resistance R4's
The other end is connect with one end of the capacitor C2, and the other end of the capacitor C2 is connect with second with reference to ground VSS, the triode
The emitter of Q3 is connect with second source, transmission of the collector of the triode Q3 also with the 2nd RS232 level signal
End connection, the anode of the diode D8 connect with described one end of the capacitor C2, the cathode of the diode D8 with it is described
The receiving end of 2nd RS232 level signal connects.
The embodiment of the present invention provides passive isolated form RS232 serial communication circuit and turns TTL module, TTL signal by RS232
Isolation module and TTL RS 232 module, so that supporting the mutual communication between RS232 protocol devices, and because communication signal
After photoelectric device is isolated, both ends communication signal be it is independent, do not interfere with each other, enhancing RS232 communication protocol signal it is anti-
Interference enhances signal integrity, and circuit uses basic original part, and manufacturing cost is lower.
In addition, circuit provided by the invention does not use external power supply to power, the DTR signal brought out by PC provides the end PC and sets
The power supply at standby end.Other external power supplys are not needed, are powered using PCTXD switching levels to another terminal circuit, during reducing power supply
It uses, apparatus is easy, and cost reduces, and is suitble to the RS232 serial communication of complex environment.
Detailed description of the invention
Fig. 1 is passive isolated form RS232 serial communication circuit structural schematic diagram provided in an embodiment of the present invention；
Fig. 2 is that RS232 provided in an embodiment of the present invention turns TTL modular circuit structural schematic diagram；
Fig. 3 is TTL signal isolation module electrical block diagram provided in an embodiment of the present invention；
Fig. 4 is TTL RS 232 modular circuit structural schematic diagram provided in an embodiment of the present invention；
Fig. 5 is power supply module electrical block diagram provided in an embodiment of the present invention.
Appended drawing reference:
Passive isolated form RS232 serial communication circuit 01；
RS232 turns TTL module 10；
TTL signal isolation module 20；
TTL RS 232 module 30；
Power supply module 40；
RS232 input signal 50；
RS232 output signal 60；
TTL output signal 70.
The embodiments will be further described with reference to the accompanying drawings for the realization, the function and the advantages of the object of the present invention.
Specific embodiment
In order to enable those skilled in the art to better understand the solution of the present invention, below in conjunction in the embodiment of the present invention
Attached drawing, technical scheme in the embodiment of the invention is clearly and completely described.Unless otherwise defined, used herein
All technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.Herein
Used term, which is only for the purpose of describing specific embodiments, in the description of the invention is not intended to limit this
Invention.
Referenced herein " embodiment " is it is meant that a particular feature, structure, or characteristic described can wrap in conjunction with the embodiments
Containing at least one embodiment of the present invention.Each position in the description occur the phrase might not each mean it is identical
Embodiment, nor the independent or alternative embodiment with other embodiments mutual exclusion.Those skilled in the art explicitly and
Implicitly understand, embodiment described herein can be combined with other embodiments.
Refering to fig. 1 to Fig. 4, present example provides a kind of passive isolated form RS232 serial communication circuit, comprising: RS232
Turn TTL module 10, TTL signal isolation module 20 and TTL RS 232 module 30, the RS232 turns TTL module 10 for by the
One RS232 level signal is converted to the first Transistor-Transistor Logic level signal or the first Transistor-Transistor Logic level signal is converted to the first RS232 level letter
Number；As shown in Figures 1 and 2, the RS232 turn TTL module 10 can be with the RS232 signal input output end (U14) of computer PC
The first RS232 level signal that the computer PC or other electronic equipments export is converted, is converted into first by connection
Transistor-Transistor Logic level signal.In addition, the RS232 turns the first TTL that TTL module 10 can also export the TTL signal isolation module 20
Level signal carries out the first RS232 level signal of conversion, and the RS232 signal input of computer PC is transmitted to by interface (U14)
Output end.It is, turning TTL module 10 by the RS232 can will carry out between RS232 level signal and TLL level signal
Mutual conversion.
The TTL signal isolation module 20 and RS232 turns the electric connection of TTL module 10, the TTL signal isolation mode
Block 20 is used for the first Transistor-Transistor Logic level signal isolation, and exports the second Transistor-Transistor Logic level signal, or by the second Transistor-Transistor Logic level signal every
From and be converted into the first Transistor-Transistor Logic level signal；As shown in Figure 1 and Figure 3, the TTL signal isolation module 20 is used for both ends
Transistor-Transistor Logic level signal carry out isolation conversion, it is, the first Transistor-Transistor Logic level signal and the second Transistor-Transistor Logic level signal pass through it is described
TTL signal isolation module 20 is isolated, and carries out mutual conversion.
The TTL RS 232 module 30 is electrically connected with the TTL signal isolation module 20, the TTL RS 232 mould
Block 30 is used to the second Transistor-Transistor Logic level signal be converted to the 2nd RS232 level signal or by the 2nd RS232 level signal
Be converted to the second Transistor-Transistor Logic level signal.As shown in figs. 1 and 4, the TTL RS 232 module 30 is isolated with the TTL signal
Module 20 connects, and the second Transistor-Transistor Logic level signal that the TTL signal isolation module 20 is exported carries out conversion the 2nd RS232 electricity
Ordinary mail number, and pass through the RS232 signal input output end that interface (U1) is transmitted to computer PC.In addition, by with computer PC's
RS232 signal input output end (U14) connection, the 2nd RS232 level that the computer PC or other electronic equipments are exported
Signal is converted, and the second Transistor-Transistor Logic level signal is converted into, to be transmitted to the TTL signal isolation module 20.It is, passing through
The TTL RS 232 module 30 can will carry out mutual conversion between TLL level signal and RS232 level signal.
Refering to fig. 1 and Fig. 5, further includes: power supply module 40, the power supply module 40 respectively with the RS232
Turn TTL module 10, TTL signal isolation module 20 and TTL RS 232 module 30 to connect, for turning TTL module for the RS232
10, TTL signal isolation module 20 and TTL RS 232 module 30 provide power supply.It is, the power supply module 40
Power supply is provided for each module of circuit.
As shown in Figure 5, the power supply module 40 includes the first power supply module 40 and the second power supply module, institute
State that the first power supply module turns TTL module 10 with the RS232 and the TTL signal isolation module 20 is connect, for by described the
An at least output signal in one RS232 level signal is converted to the first power supply, and turns the power supply of TTL module 10 for the RS232
And the first Transistor-Transistor Logic level signal end power supply of the TTL signal isolation module 20；Due to 20 liang of the TTL signal isolation module
The signal at end is isolated, and in present example, passes through first power supply module 40 and second source power supply mould
Block 40 is respectively that the feeder ear at 20 both ends of TTL signal isolation module is individually powered, so that TTL signal isolation module
20 liang of end signals are mutually isolated, avoid influencing each other.As shown in figure 1 and figure 5, first power supply module 40 passes through institute
It states RS232 to connect with computer PC, and an at least output signal in RS232 signal that computer PC is exported is converted into the first power supply,
Such as the PCDTR signal or PCTXD signal of the RS232 signal input output end (U14) of computer PC in Fig. 1 and Fig. 5.First electricity
Source power supply module 40 carries out storage output to the PCDTR signal or PCTXD signal, with for TTL signal isolation module 20
The power supply of one Transistor-Transistor Logic level signal end.First is converted to by an at least output signal in the RS232 signal that exports the computer PC
Power supply avoids the use of external power supply.
Second power supply module is connect with the TTL RS 232 module 30 and the TTL signal isolation module 20, is used
In by the 2nd RS232 level signal an at least output signal convert second source, and be the TTL RS 232 mould
The power supply of block 30 and the second Transistor-Transistor Logic level signal end power supply of the TTL signal isolation module 20.Similarly, the second power supply mould
Block is also the TXD_DUT signal by the RS232 signal input output end (U1) of computer PC other end of in such as Fig. 1 and Fig. 5
Storage output is carried out, to avoid making for external power supply for the power supply of the second Transistor-Transistor Logic level signal end of TTL signal isolation module 20
With.
Refering to Fig. 5, first power supply module 40 includes: diode D11, diode D12, diode D13, two poles
Pipe D14, resistance R7 and capacitor C1, the diode D11, diode D12, diode D13, the first rectification of diode D14 composition
Circuit, first rectification circuit input end turn TTL module 10 with the RS232 and connect, first rectification circuit output end
It is connect with one end of the resistance R7, the other end of the resistance R7 is connect with one end of the capacitor C1, the capacitor C1's
The other end is connect with second with reference to ground VSS, and described one end and the RS232 of the capacitor C1 turns TTL module 10 and described
The signal-powered end connection of first Transistor-Transistor Logic level of TTL signal isolation module 20.As shown in figure 1 and figure 5, the diode D11,
Diode D12, diode D13, diode D14 are to the output signal of the RS232 signal input output end (U14) of the computer PC
PCTXD carries out rectification output, and by the resistance R7 for capacitor C1 charging, the capacitor C1 after charging is exportable stable
First power supply, to be the first Transistor-Transistor Logic level signal end module for power supply of the TTL signal isolation module 20.
Further, in an example of the present invention, first power supply module 40 includes: diode D5, electricity
The anode of resistance R60 and resistance R6, the diode D5 turn TTL module 10 with the RS232 and connect, the cathode of the diode D5
It is connect with one end of the resistance R60, the other end of the resistance R60 is connect with one end of the resistance R6, the resistance R6
The other end with first with reference to ground LGND connect, described one end of the resistance R6 also turn with the RS232 TTL module 10 and
The signal-powered end connection of first Transistor-Transistor Logic level of the TTL signal isolation module 20.As shown in figure 1 and figure 5, the diode
D5 carries out rectification output to the output signal PCDTR of the RS232 signal input output end (U14) of the computer PC, and passes through institute
It is the first Transistor-Transistor Logic level signal end module for power supply of the TTL signal isolation module 20 after stating resistance R60 and resistance R6 partial pressure.?
It is exactly that two different structure power supply modes can be used to provide the first power supply in first power supply module 40.
In another example of the invention, two power supply modes can also be combined.As shown in Figure 5, by double
Two different power supply modes are combined output by diode D15.So that first power supply is more stable.
Refering to Fig. 5, the second source power supply module 40 includes: diode D6, diode D7, diode D9, diode
D10, resistance R63 and capacitor C24, the diode D6, diode D7, diode D9, diode D10 form the second rectified current
Road, second rectification circuit input end turn TTL module 10 with the RS232 and connect, second rectification circuit output end with
One end of the resistance R63 connects, and the other end of the resistance R63 is connect with one end of the capacitor C24, the capacitor C24
The other end with second with reference to ground VSS connect, described one end of the capacitor C24 also with the TTL RS 232 module 30 and
The signal-powered end connection of second Transistor-Transistor Logic level of the TTL signal isolation module 20.As shown in figure 1 and figure 5, the diode
D6, diode D7, diode D9, diode D10 believe the output of the RS232 signal input output end (U1) of other end computer PC
Number TXD_DUT carries out rectification output, and is that the capacitor C24 charges by the resistance R63, and the capacitor C24 after charging can be defeated
Stable second source out, to be the second Transistor-Transistor Logic level signal end module for power supply of the TTL signal isolation module 20.
Circuit provided by the invention does not use external power supply to power, the DTR signal brought out by PC, DTR signal: data equipment
Signal is got out, -12V under general state gets out state and continues 12V, provides the power supply at PC end equipment end using DTR signal.
Other external power supplys are not needed, in addition, being powered using PCTXD switching levels to other end circuitry, are made during reducing power supply
With apparatus is easy, and cost reduces.
Refering to fig. 1 and Fig. 2, the RS232 turn TTL module 10 include: the first transmission signal conversion module and first receive
Signal conversion module；The first Transistor-Transistor Logic level that the first transmission signal conversion module is used to export TTL signal isolation module 20
Signal converts the first RS232 level signal, and is transmitted to computer PC.Described first, which receives signal conversion module, is used for the electricity
First RS232 level signal of brain PC output is converted into the first Transistor-Transistor Logic level signal, and is transmitted to the TTL signal isolation module
20。
As shown in Figure 2, the first transmission signal conversion module includes triode Q1, resistance R57, resistance R56, capacitor
C5 and diode D4, one end of the resistance R57 are connect with the first transmitting terminal of the TTL signal isolation module 20, the electricity
The other end of resistance R57 is connect with the base stage of the triode Q1, one end of the collector of the triode Q1 and the resistance R56
Connection, the other end of the resistance R56 are connect with one end of the capacitor C5, and the other end of the capacitor C5 and first is with reference to ground
The emitter of LGDN connection, the triode Q1 is connect with the first power supply, and the collector of the triode Q1 is also with described first
The receiving end of RS232 level signal connects, and the anode of the diode D4 is connect with described one end of the capacitor C5, and described two
The cathode of pole pipe D4 is connect with the transmitting terminal of the first RS232 level signal；
The triode Q1 carries out on or off working condition under the action of the first Transistor-Transistor Logic level signal, in institute
When stating triode Q1 conducting, under the action of the capacitor C5 and the first power supply, high level is exported；End in the triode Q1
When, since the passive isolated form RS232 serial communication circuit work is in semiduplex mode.At this point, the yin of the diode D4
Pole is under the action of the transmitting terminal PCTXD negative signal of the first RS232 level signal, diode D4 conducting.And by described two
The junction pole pipe D4 and capacitor C5 level drags down.It is under the action of the capacitor C5 and the diode D4, transmission of electricity is flat
Simultaneously voltage output is dragged down, so that the first Transistor-Transistor Logic level signal is converted into the first RS232 level signal.
It is, by the effect of the capacitor C5 and diode D4, so that the diode D4 and capacitor C5 is handed over
The voltage at the place of connecing level when output is 0 signal is maintained between -3V to -15V, and when output is 1 signal, level is maintained at -3V
Between to -15V.
As shown in Figure 2, the first reception signal conversion module includes triode Q5, resistance R58 and resistance R59, institute
The one end for stating resistance R58 is connect with the transmitting terminal of the first RS232 level signal, three described in the other end of the resistance R58
The base stage of pole pipe Q5 connects, and the emitter of the triode Q5 is connect with described first with reference to ground LGDN, the triode Q5's
Collector is connect with one end of the resistance R59, and the other end of the resistance R59 is connect with first power supply, three pole
The collector of pipe Q5 is also connect with the first receiving end of the TTL signal isolation module 20.The triode Q5 is described first
On or off working condition is carried out under the action of RS232 level signal, so that the level of first power supply be exported.It is described
The voltage of first power supply is 5V.It is, 5V level voltage is exported in triode Q5 cut-off；In the triode
When Q5 is connected, by 0V voltage output, so that the first RS232 level signal is converted into the first Transistor-Transistor Logic level signal.
It further, further include zener diode D1 in an example of the present invention, the sun of the zener diode D1
Pole is connect with the base stage of the triode Q5, and the cathode of the zener diode D1 is connect with described first with reference to ground LGDN.It is logical
It crosses the zener diode D1 and reverse protection is carried out to the triode Q5, the direction the triode Q5 is avoided to puncture.
Refering to fig. 1 and Fig. 3, the TTL signal isolation module 20 includes: the first optocoupler U15 and the second optocoupler U18, described
The collector of first optocoupler U15 is connect by resistance R62 with the first power supply, the emitter of the first optocoupler U15 with it is described
RS232 turns the transmission signal end connection of TTL module 10, and the cathode of the first optocoupler U15 is connect with second with reference to ground VSS, institute
The anode for stating the first optocoupler U15 is connect with the signal sending end of the TTL RS 232 module 30；
The collector of the second optocoupler U18 is connect by resistance R5 with second source, the transmitting of the second optocoupler U18
Pole is connect with the reception signal end of the TTL RS 232 module 30, and the cathode of the second optocoupler U18 and first is with reference to ground
The anode of LGND connection, the second optocoupler U18 is connect with the RS232 signal receiving end for turning TTL module 10.
Refering to fig. 1 and Fig. 4, the TTL RS 232 module 30 include: that the second transmission signal conversion module and second receive
Signal conversion module；Described second, which sends signal conversion module, is used for the 2nd RS232 level of another computer PC output
Signal is converted into the second Transistor-Transistor Logic level signal, and is transmitted to the TTL signal isolation module 20.Described second receives signal conversion
The second Transistor-Transistor Logic level signal that module is used to export TTL signal isolation module 20 converts the 2nd RS232 level signal, and transmits
To other end computer PC.
The second transmission signal conversion module includes triode Q2, resistance R3 and resistance R2, one end of the resistance R3
It is connect with the receiving end of the 2nd RS232 level signal, the base stage connection of triode Q2 described in the other end of the resistance R3,
The emitter of the triode Q5 is connect with described second with reference to ground VSS, the collector of the triode Q2 and the resistance R2
One end connection, the other end of the resistance R2 connect with second source, the collector of the triode Q2 also with TTL letter
The second transmitting terminal connection of number isolation module 20；The triode Q2 is carried out under the action of the 2nd RS232 level signal
On or off working condition, so that the level of the second source be exported.The voltage of the second source is 5V.Also
It is, in triode Q2 cut-off, 5V level voltage to be exported；In triode Q2 conducting, by 0V voltage output, from
And the 2nd RS232 level signal is converted into the second Transistor-Transistor Logic level signal.
It further, further include zener diode D2 in an example of the present invention, the sun of the zener diode D2
Pole is connect with the base stage of the triode Q2, and the cathode of the zener diode D2 is connect with described first with reference to ground LGDN.It is logical
It crosses the zener diode D2 and reverse protection is carried out to the triode Q2, the direction the triode Q2 is avoided to puncture.
The second reception signal conversion module includes triode Q3, resistance R1, resistance R4, capacitor C2 and diode D8,
One end of the resistance R1 is connect with the second receiving end of the TTL signal isolation module 20, the other end of the resistance R1 with
The base stage of the triode Q3 connects, and the collector of the triode Q3 is connect with one end of the resistance R4, the resistance R4
The other end connect with one end of the capacitor C2, the other end of the capacitor C2 with second with reference to ground VSS connect, three pole
The emitter of pipe Q3 is connect with second source, hair of the collector of the triode Q3 also with the 2nd RS232 level signal
Sending end connection, the anode of the diode D8 are connect with described one end of the capacitor C2, the cathode of the diode D8 and institute
State the receiving end connection of the 2nd RS232 level signal.
The triode Q3 carries out on or off working condition under the action of the second Transistor-Transistor Logic level signal, in institute
When stating triode Q3 conducting, under the action of the capacitor C2 and second source, high level is exported；End in the triode Q3
When, since the passive isolated form RS232 serial communication circuit work is in semiduplex mode.At this point, the yin of the diode D8
Pole is under the action of the transmitting terminal RXD_DUT negative signal of the 2nd RS232 level signal, diode D8 conducting.And it will be described
The junction diode D8 and capacitor C8 level drags down.Under the action of the capacitor C2 and the diode D8, it will transmit electricity
Horizontal drawing is low and voltage output, so that the second Transistor-Transistor Logic level signal is converted into the 2nd RS232 level signal.
It is, by the effect of the capacitor C2 and diode D8, so that the diode D8 and capacitor C2 is handed over
The voltage at the place of connecing level when output is 0 signal is maintained between -3V to -15V, and when output is 1 signal, level is maintained at 3V
To between 15V.
More specifically, RS232 serial ports access input signal is RS232 signal, and RS232 signal accesses TTL conversion electricity
Road, by RS232 level translation Transistor-Transistor Logic level signal, using two triode ONs by so that RS232 signal is converted into TTL letter
Number, wherein D1TVS pipe is the BE reverse breakdown of Q4 in order to prevent, and 15V when the minimum voltage of TXD, the BE pressure resistance of Q4 is 6V or so.
After being converted into TTL signal, isolation signals are carried out by photoelectric device TLP181_TPRF, are turned between the signal of TLP181_TPRF
Changing the time is sufficient for communicating between signal.After isolation, device talk both ends communication signal is not interfere with each other, and guarantees that signal is complete
Whole property, the communication signal after conversion isolation can convert RS232 signal entering TTL, so that communicating between RS232 interface, fit
Close the RS232 serial communication of complex environment.
It is specifically had the advantages that in addition, this embodiment of the present invention provides passive isolated form RS232 serial communication circuit
1, using passive circuit, by testing RS232 interface signal, wherein discovery DTR signal is ready to, it is in logic
" 0 ", level signal 12V supply main signalling equipment end using DTR characteristic, recycle the conversion of DUT equipment end RS232TX signal
For circuit power, it is not necessarily to external power supply, reduces cost.
2, RS232 converts TTL circuit using transistor circuit design, using triode ON by patrolling so that RS232 is counter
Volume level signal is converted into as TTL signal, and circuit is simple, easy to accomplish.
3, zener diode D1, D2TVS pipe is reversely to hit between the emitter of triode Q2, Q5 and base stage BE in order to prevent
It wears (when the minimum voltage of TXD 15V, the BE pressure resistance of Q2, Q5 are 6V or so).
4, two end signal of Transistor-Transistor Logic level signal is isolated using photoelectric isolating device, so that signal is not interfere with each other, makes signal integrity
Property.
5, Transistor-Transistor Logic level signal switchs to RS2323 level signal, due to the effect of diode D4, D8 and capacitor C2, C5, so that
Voltage in diode D4, D8 and the junction capacitor C2, C5 is maintained at -3V~-15V, supports 600~115200bps.
The embodiment of the present invention provides passive isolated form RS232 serial communication circuit and turns TTL module 10, TTL letter by RS232
Number isolation module 20 and TTL RS 232 module 30, so that supporting the mutual communication between RS232 protocol devices, and because logical
Interrogate signal after photoelectric device is isolated, both ends communication signal be it is independent, do not interfere with each other, enhancing RS232 communications protocol letter
Number anti-interference, enhance signal integrity, circuit uses basic original part, and manufacturing cost is lower.
In addition, circuit provided by the invention does not use external power supply to power, the DTR signal brought out by PC provides the end PC and sets
The power supply at standby end.Other external power supplys are not needed, are powered using PCTXD switching levels to another terminal circuit, during reducing power supply
It uses, apparatus is easy, and cost reduces.
The above is only the embodiment of the present invention, are not intended to limit the scope of the patents of the invention, although with reference to the foregoing embodiments
Invention is explained in detail, still can be to aforementioned each specific reality for coming for those skilled in the art
It applies technical solution documented by mode to modify, or equivalence replacement is carried out to part of technical characteristic.It is all to utilize this
The equivalent structure that description of the invention and accompanying drawing content are done directly or indirectly is used in other related technical areas, similarly
Within the invention patent protection scope.
In the description of this specification, reference term " one embodiment ", " some embodiments ", " example ", " specifically show
The description of example " or " some examples " etc. means specific features, structure, material or spy described in conjunction with this embodiment or example
Point is included at least one embodiment or example of the invention.In the present specification, schematic expression of the above terms are not
Centainly refer to identical embodiment or example.Moreover, particular features, structures, materials, or characteristics described can be any
One or more embodiment or examples in can be combined in any suitable manner.
Although the embodiments of the present invention has been shown and described above, it is to be understood that above-described embodiment is example
Property, it is not considered as limiting the invention, those skilled in the art are not departing from the principle of the present invention and objective
In the case where can make changes, modifications, alterations, and variations to the above described embodiments within the scope of the invention.
Claims (10)
1. a kind of passive isolated form RS232 serial communication circuit characterized by comprising
RS232 turns TTL module, and the RS232 turns TTL module for the first RS232 level signal to be converted to the first Transistor-Transistor Logic level
First Transistor-Transistor Logic level signal is converted to the first RS232 level signal by signal；
TTL signal isolation module, the TTL signal isolation module and the RS232 turn the electric connection of TTL module, the TTL letter
Number isolation module is used for the first Transistor-Transistor Logic level signal isolation, and exports the second Transistor-Transistor Logic level signal, or by the second Transistor-Transistor Logic level
Signal isolation is simultaneously converted into the first Transistor-Transistor Logic level signal；
TTL RS 232 module, the TTL RS 232 module and the TTL signal isolation module are electrically connected, and the TTL turns
RS232 module is used to be converted to the second Transistor-Transistor Logic level signal the 2nd RS232 level signal or the 2nd RS232 is electric
Ordinary mail number is converted to the second Transistor-Transistor Logic level signal.
2. passive isolated form RS232 serial communication circuit according to claim 1, which is characterized in that further include: power supply supplies
Electric module, the power supply module turn TTL module, TTL signal isolation module and TTL RS 232 mould with the RS232 respectively
Block connection, provides power supply for turning TTL module, TTL signal isolation module and TTL RS 232 module for the RS232.
3. passive isolated form RS232 serial communication circuit according to claim 2, which is characterized in that the power supply power supply
Module includes the first power supply module and the second power supply module, first power supply module and the RS232 turn TTL module and
TTL signal isolation module connection, for at least output signal in the first RS232 level signal to be converted to the
One power supply, and supplied for the RS232 the first Transistor-Transistor Logic level signal end for turning TTL module for power supply and the TTL signal isolation module
Electricity；
Second power supply module is connect with the TTL RS 232 module and the TTL signal isolation module, and being used for will be described
An at least output signal in 2nd RS232 level signal converts second source, and for the TTL RS 232 module for power supply with
And the second Transistor-Transistor Logic level signal end power supply of the TTL signal isolation module.
4. passive isolated form RS232 serial communication circuit according to claim 3, which is characterized in that first power supply
Power supply module includes: diode D11, diode D12, diode D13, diode D14, resistance R7 and capacitor C1, two pole
Pipe D11, diode D12, diode D13, diode D14 form the first rectification circuit, first rectification circuit input end with
The RS232 turns the connection of TTL module, and first rectification circuit output end is connect with one end of the resistance R7, the resistance
The other end of R7 is connect with one end of the capacitor C1, and the other end of the capacitor C1 is connect with second with reference to ground VSS, the electricity
The described one end and the RS232 for holding C1 turn TTL module and the first Transistor-Transistor Logic level signal of the TTL signal isolation module supplies
Electric end connection.
5. passive isolated form RS232 serial communication circuit according to claim 3, which is characterized in that first power supply
Power supply module includes: that the anode of diode D5, resistance R60 and resistance R6, the diode D5 and the RS232 turn TTL module
Connection, the cathode of the diode D5 are connect with one end of the resistance R60, the other end and the resistance of the resistance R60
One end of R6 connects, the other end of the resistance R6 with first with reference to LGND connect, described one end of the resistance R6 also with
The RS232 turns the signal-powered end connection of the first Transistor-Transistor Logic level of TTL module and the TTL signal isolation module.
6. passive isolated form RS232 serial communication circuit according to claim 3, which is characterized in that the second source
Power supply module includes: diode D6, diode D7, diode D9, diode D10, resistance R63 and capacitor C24, the diode
D6, diode D7, diode D9, diode D10 form the second rectification circuit, second rectification circuit input end with it is described
RS232 turns the connection of TTL module, and second rectification circuit output end is connect with one end of the resistance R63, the resistance R63
The other end connect with one end of the capacitor C24, the other end of the capacitor C24 with second with reference to ground VSS connect, the electricity
Hold second Transistor-Transistor Logic level signal of the described one end of C24 also with the TTL RS 232 module and the TTL signal isolation module
Feeder ear connection.
7. passive isolated form RS232 serial communication circuit according to claim 1, which is characterized in that the RS232 turns
TTL module includes: that the first transmission signal conversion module and first receive signal conversion module；
The first transmission signal conversion module includes triode Q1, resistance R57, resistance R56, capacitor C5 and diode D4, institute
The one end for stating resistance R57 is connect with the first transmitting terminal of the TTL signal isolation module, the other end of the resistance R57 and institute
The base stage connection of triode Q1 is stated, the collector of the triode Q1 is connect with one end of the resistance R56, the resistance R56
The other end connect with one end of the capacitor C5, the other end of the capacitor C5 with first with reference to ground LGDN connect, described three
The emitter of pole pipe Q1 is connect with the first power supply, the collector of the triode Q1 also with the first RS232 level signal
Receiving end connection, the anode of the diode D4 connect with described one end of the capacitor C5, the cathode of the diode D4 and
The transmitting terminal of the first RS232 level signal connects；
The first reception signal conversion module includes triode Q5, resistance R58 and resistance R59, one end of the resistance R58 with
The transmitting terminal of the first RS232 level signal connects, the base stage connection of triode Q5 described in the other end of the resistance R58,
The emitter of the triode Q5 is connect with described first with reference to ground LGDN, the collector and the resistance of the triode Q5
One end of R59 connects, and the other end of the resistance R59 is connect with first power supply, the collector of the triode Q5 also with
First receiving end of the TTL signal isolation module connects.
8. passive isolated form RS232 serial communication circuit according to claim 7, which is characterized in that further include pressure stabilizing two
Pole pipe D1, the anode of the zener diode D1 are connect with the base stage of the triode Q5, the cathode of the zener diode D1
It is connect with described first with reference to ground LGDN.
9. passive isolated form RS232 serial communication circuit according to claim 1, which is characterized in that the TTL signal every
Include: from module
The collector of first optocoupler U15, the first optocoupler U15 is connect by resistance R62 with the first power supply, first optocoupler
The emitter of U15 is connect with the RS232 transmission signal end for turning TTL module, the cathode of the first optocoupler U15 and the second ginseng
Ground VSS connection is examined, the anode of the first optocoupler U15 is connect with the signal sending end of the TTL RS 232 module；
The collector of second optocoupler U18, the second optocoupler U18 is connect by resistance R5 with second source, second optocoupler
The emitter of U18 is connect with the reception signal end of the TTL RS 232 module, the cathode of the second optocoupler U18 and the first ginseng
Ground LGND connection is examined, the anode of the second optocoupler U18 is connect with the RS232 signal receiving end for turning TTL module.
10. passive isolated form RS232 serial communication circuit according to claim 1, which is characterized in that the TTL turns
RS232 module includes: that the second transmission signal conversion module and second receive signal conversion module；
The second transmission signal conversion module includes triode Q2, resistance R3 and resistance R2, one end of the resistance R3 and institute
The receiving end connection of the 2nd RS232 level signal is stated, the base stage connection of triode Q2 described in the other end of the resistance R3 is described
The emitter of triode Q5 is connect with described second with reference to ground VSS, and the one of the collector of the triode Q2 and the resistance R2
End connection, the other end of the resistance R2 connect with second source, the collector of the triode Q2 also with the TTL signal every
The second transmitting terminal connection from module；
The second reception signal conversion module includes triode Q3, resistance R1, resistance R4, capacitor C2 and diode D8, described
One end of resistance R1 is connect with the second receiving end of the TTL signal isolation module, the other end of the resistance R1 and described three
The base stage of pole pipe Q3 connects, and the collector of the triode Q3 is connect with one end of the resistance R4, and the resistance R4's is another
End is connect with one end of the capacitor C2, and the other end of the capacitor C2 is connect with second with reference to ground VSS, the triode Q3's
Emitter is connect with second source, and the collector of the triode Q3 also connects with the transmitting terminal of the 2nd RS232 level signal
It connects, the anode of the diode D8 is connect with described one end of the capacitor C2, the cathode of the diode D8 and described second
The receiving end of RS232 level signal connects.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910058153.4A CN109547010A (en) | 2019-01-22 | 2019-01-22 | Passive isolated form RS232 serial communication circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910058153.4A CN109547010A (en) | 2019-01-22 | 2019-01-22 | Passive isolated form RS232 serial communication circuit |
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| CN109547010A true CN109547010A (en) | 2019-03-29 |
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| CN201910058153.4A Pending CN109547010A (en) | 2019-01-22 | 2019-01-22 | Passive isolated form RS232 serial communication circuit |
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