CN109951405A - Signal-isolated transmission method and circuit based on transformer and operational amplifier - Google Patents
Signal-isolated transmission method and circuit based on transformer and operational amplifier Download PDFInfo
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- CN109951405A CN109951405A CN201910275296.0A CN201910275296A CN109951405A CN 109951405 A CN109951405 A CN 109951405A CN 201910275296 A CN201910275296 A CN 201910275296A CN 109951405 A CN109951405 A CN 109951405A
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Abstract
The invention belongs to technical field of communication equipment, the signal-isolated transmission method based on transformer and operational amplifier is disclosed, comprising: by the primary coil of a Transistor-Transistor Logic level signal input transformer；Transformer secondary coil will generate mutation voltage when the Transistor-Transistor Logic level signal of input jumps；The mutation voltage of secondary coil is reduced to another Transistor-Transistor Logic level output signal by the hysteresis loop comparator that operational amplifier is constituted；Wherein, the threshold values that the hysteresis loop comparator jumps upwards is VT+, the threshold values VT- that hysteresis loop comparator jumps downwards, the negative sense mutation voltage at the relatively non-punctuate end in transformer secondary coil punctuate end is-VS, the forward mutation assay voltage at the relatively non-punctuate end in transformer secondary coil punctuate end is VS, 0 < VT+ < VS of-VS < VT- <.And the circuit for applying the isolation transmission method is disclosed, the present invention can reduce the cost of the isolation transmission of Transistor-Transistor Logic level signal, and realize isolation features.
Description
Technical field
The invention belongs to technical field of communication equipment, more particularly to are passed based on the signal isolation of transformer and operational amplifier
Transmission method and circuit.
Background technique
Communication or monitoring system are carried out in the signal that communication equipment or communication system back warp Chang Douhui use Transistor-Transistor Logic level
Operating status.But sometimes two equipment rooms not altogether or even in same equipment between disparate modules can not altogether, such one
Carry out two equipment rooms or two intermodules just have uncertain potential difference, if they, which are connected directly, can interfere
Their normal operation causes communication failure, or even burns out machine.To solve this problem, it will usually the TTL for transmitting needs
Level signal is transmitted again after carrying out electrical isolation, so just solves the problems, such as common mode interference, also can normal communication.For solution
The certainly isolation transmission problem of Transistor-Transistor Logic level signal, the prior art forms isolation frequently with photoelectrical coupler, although this way can
Row, but photoelectrical coupler price is higher, when especially having very multiple signals needs isolation transmission, if all using photoelectric coupling
Device is isolated, and cost will be very high.Ethernet realizes the isolation transmission of network data, cost usually using network transformer
It is much lower to will use opto-coupler chip.But transformer can only couple AC signal, therefore TTL electricity cannot be directly carried out with transformer
The isolation of ordinary mail number is transmitted.
Summary of the invention
The embodiment of the present invention is designed to provide a kind of signal-isolated transmission side based on transformer and operational amplifier
Method and circuit, can reduce the cost of the isolation transmission of Transistor-Transistor Logic level signal, and realize isolation features.
The embodiments of the present invention are implemented as follows:
Signal-isolated transmission method based on transformer and operational amplifier, comprising:
By the primary coil of input transformer after a Transistor-Transistor Logic level input signal one resistance of series connection；
The secondary coil of transformer will generate mutation voltage when the signal of the Transistor-Transistor Logic level of input jumps；
The mutation voltage of secondary coil is reduced to another Transistor-Transistor Logic level and exported by the hysteresis loop comparator being made of operational amplifier
Signal；
Wherein, the threshold values that the hysteresis loop comparator jumps upwards is VT+, the threshold values VT- that hysteresis loop comparator jumps downwards, is become
The negative sense mutation voltage at the relatively non-punctuate end in depressor secondary coil punctuate end is-VS, and transformer secondary coil punctuate end is relatively non-
The forward mutation assay voltage at punctuate end is VS, 0 < VT+ < VS of-VS < VT- <.
Using the circuit of the isolation transmission method, comprising: transformer, operational amplifier, first resistor, second resistance,
3rd resistor and the 4th resistance, a termination Transistor-Transistor Logic level signal input part of first resistor, the other end connect transformer
Punctuate end, the non-punctuate of transformer terminates the first signal ground, the non-punctuate termination second of transformer secondary coil
Signal ground, one end of the punctuate termination second resistance of transformer secondary coil, another termination operational amplifier of second resistance
Positive input terminal, the both ends of 3rd resistor connect the positive input terminal and output end of operational amplifier, the both ends difference of the 4th resistance respectively
With connecing second signal with the negative input end of operational amplifier, the output end of operational amplifier is as the Transistor-Transistor Logic level signal after isolation
Output end.
The embodiment of the present invention is compared with using optocoupler or magnetic coupling device, using based on transformer and operational amplifier
The isolation and transmission circuit cost of Transistor-Transistor Logic level signal will be much lower, less than the former half, especially in multichannel Transistor-Transistor Logic level
It is more obvious that signal needs to be isolated cost advantage in the system of transmission.
Detailed description of the invention
Fig. 1 is isolation and transmission circuit schematic diagram of the present invention；
Fig. 2 is the signal waveforms of each position in Fig. 1.
Specific embodiment
In order to make the objectives, technical solutions, and advantages of the present invention clearer, with reference to the accompanying drawings and embodiments, right
The present invention is further elaborated.It should be appreciated that described herein, specific examples are only used to explain the present invention, not
For limiting the present invention.
Specific implementation of the invention is described in detail below in conjunction with specific embodiment:
Signal-isolated transmission method based on transformer and operational amplifier, comprising:
By the primary coil of input transformer after a Transistor-Transistor Logic level input signal one resistance of series connection；
The secondary coil of transformer will generate mutation voltage when the signal of the Transistor-Transistor Logic level of input jumps；
The mutation voltage of secondary coil is reduced to another Transistor-Transistor Logic level and exported by the hysteresis loop comparator being made of operational amplifier
Signal；
Wherein, the threshold values that the hysteresis loop comparator jumps upwards is VT+, the threshold values VT- that hysteresis loop comparator jumps downwards, is become
The negative sense mutation voltage at the relatively non-punctuate end in depressor secondary coil punctuate end is-VS, and transformer secondary coil punctuate end is relatively non-
The forward mutation assay voltage at punctuate end is VS, 0 < VT+ < VS of-VS < VT- <.
Using the circuit of the isolation transmission method, comprising: transformer, operational amplifier, first resistor, second resistance,
3rd resistor and the 4th resistance, a termination Transistor-Transistor Logic level signal input part of first resistor, the other end connect transformer
Punctuate end, the non-punctuate of transformer terminates the first signal ground, the non-punctuate termination second of transformer secondary coil
Signal ground, one end of the punctuate termination second resistance of transformer secondary coil, another termination operational amplifier of second resistance
Positive input terminal, the both ends of 3rd resistor connect the positive input terminal and output end of operational amplifier, the both ends difference of the 4th resistance respectively
With connecing second signal with the negative input end of operational amplifier, the output end of operational amplifier is as the Transistor-Transistor Logic level signal after isolation
Output end.
Concrete scheme and principle of the invention is as follows:
A kind of specific implementation circuit such as Fig. 1 of the isolation transmission of the Transistor-Transistor Logic level signal based on transformer and operational amplifier
It is shown, but the physical circuit that the present invention program realizes is not limited only to this, and circuit can also have other specific connection types, as long as
Use scheme proposed by the invention within the protection of the invention patent.Entire circuit is mainly by resistance R1, transformer
T1, resistance R2, R3, R4 and operational amplifier U1 are constituted.Specific connection type is as follows:
1. 1 foot of resistance R1 is the isolation and transmission circuit input terminal of Transistor-Transistor Logic level signal；
2. 2 feet of resistance R1 connect the punctuate end of transformer T1 primary coil；
3. the non-punctuate of transformer T1 primary coil terminates GND_1 (GND_1 signal ground, be isolated with GND_2)
4. 1 foot of the punctuate terminating resistor R2 of transformer T1 secondary coil；
5. the non-punctuate of transformer T1 secondary coil terminates GND_2；
6. 2 feet of resistance R2 connect the positive input terminal of operational amplifier U1 and 1 foot of resistance R3；
7. 2 feet of resistance R3 connect the output end of operational amplifier U1；
8. 1 foot of resistance R4 meets GND_2；
9. 2 feet of resistance R4 connect the negative input end of operational amplifier U1；
When the signal of the Transistor-Transistor Logic level of signal input part becomes 1 from 0, at the beginning of thering is electric current to flow to transformer T1 by resistance R1
Grade coil then flows into GND_1.Because the electric current of transformer T1 primary coil cannot be mutated, in the Transistor-Transistor Logic level of input terminal
Signal, which becomes 1 moment transformer T1 primary coil punctuate end voltage from 0, will sport VP, then as transformer T1 primary line
Loop current is gradually increased and reduces, until 0V.The voltage at the relatively non-punctuate end in transformer T1 secondary coil punctuate end also will mutation
For VSAnd gradually decrease to 0V.
When the signal of the Transistor-Transistor Logic level of signal input part becomes 0 from 1, transformer T1 primary coil is flowed to again from resistance R1
The electric current for flowing to GND_1 is gradually reduced.Because the electric current of transformer T1 primary coil cannot be mutated, in the TTL of input terminal
The signal of level, which becomes 0 moment transformer T1 primary coil punctuate end voltage from 1, will sport-VP, then as transformer
T1 primary current is gradually reduced and increases, until 0V.The voltage at the relatively non-punctuate end in transformer T1 secondary coil punctuate end
Also-V will be sportedSAnd it is gradually increased to 0V.
Resistance R2, R3, R4 and operational amplifier U1 together form a positive hysteresis loop comparator, remember hysteresis loop comparator
The threshold values jumped upwards is VT+, and the threshold values that note hysteresis loop comparator jumps downwards is VT-.The resistance value for adjusting R2, R3 is adjustable stagnant
The threshold values of comparator is returned, the resistance value of R4 need to be determined by the resistance value of R2, R3.
R1 and transformer T1 is adjusted, V is madeSIt is as big as possible, then adjust the resistance value of resistance R2, R3 and make 0 < VT+ of-VS < VT- <
< VS.For example when the Transistor-Transistor Logic level signal high voltage of input is 3.3V, operational amplifier supply voltage is respectively+3.3V and -3.3V
When, the value of resistance R1 can be 100 Ω, and the value of resistance R2, R3 can be 1M Ω, and transformer primary and secondary turn ratio is 1: 2,
The inductance of transformer is 1uH or more.
When the Transistor-Transistor Logic level signal of signal input part remains 0 or 1, transformer T1 secondary coil does not have signal output,
Voltage is 0V.Operational amplifier U1 will keep current output state at this time.
When the Transistor-Transistor Logic level signal of signal input part becomes 1 from 0, transformer T1 secondary coil punctuate end voltage will be jumped
For VS and it is gradually reduced.High level will be exported because of 0 < VT+ < VS, operational amplifier U1 in the moment of voltage jump；Become later
Depressor T1 secondary coil punctuate end voltage is reduced to 0V, and operational amplifier U1 will keep current output state.
When the Transistor-Transistor Logic level signal of signal input part becomes 0 from 1, transformer T1 secondary coil punctuate end voltage will be jumped
For VS and it is gradually reduced.Voltage jump moment because of-VS < VT- < 0, operational amplifier U1 will export low level at this time；
Transformer T1 secondary coil punctuate end voltage is upgraded to 0V later, and operational amplifier U1 will keep current output state.
In conclusion circuit realizes the isolation transmission of Transistor-Transistor Logic level signal.The signal waveform of each position is as schemed in circuit
Shown in 2.
In the embodiment of the present invention, need using one with two coils of primary coil and secondary coil transformer and
One operational amplifier；One end of primary coil of one resistance one end and transformer is connected to together, the primary coil of transformer
Other end ground connection or connect a certain reference voltage, the signal of Transistor-Transistor Logic level is inputted from the other end of the resistance.Work as Transistor-Transistor Logic level
Signal when jump because the electric current of transformer will not mutate, the voltage at resistance both ends is just not yet
It can mutate, so the voltage at transformer both ends can be jumped with the jump of the signal of Transistor-Transistor Logic level, transformer
Secondary coil both ends have corresponding signal output；A threshold values is built less than pulse amplitude with operational amplifier and resistance
Hysteresis loop comparator；It is Transistor-Transistor Logic level signal with the shift pulse signal that hysteresis loop comparator exports the secondary coil of transformer, from
And realize the isolation transmission of Transistor-Transistor Logic level signal.
The embodiment of the present invention is compared with using optocoupler or magnetic coupling device, using based on transformer and operational amplifier
The isolation and transmission circuit cost of Transistor-Transistor Logic level signal will be much lower, less than the former half, especially in multichannel Transistor-Transistor Logic level
It is more obvious that signal needs to be isolated cost advantage in the system of transmission.
The foregoing is merely illustrative of the preferred embodiments of the present invention, is not intended to restrict the invention, all in essence of the invention
Made any modifications, equivalent replacements, and improvements etc., should all be included in the protection scope of the present invention within mind and principle.
Claims (2)
1. the signal-isolated transmission method based on transformer and operational amplifier characterized by comprising
By the primary coil of input transformer after a Transistor-Transistor Logic level input signal one resistance of series connection；
The secondary coil of transformer will generate mutation voltage when the signal of the Transistor-Transistor Logic level of input jumps；
The mutation voltage of secondary coil is reduced to another Transistor-Transistor Logic level output letter by the hysteresis loop comparator being made of operational amplifier
Number；
Wherein, the threshold values that the hysteresis loop comparator jumps upwards is VT+, the threshold values VT- that hysteresis loop comparator jumps downwards, transformer
The negative sense mutation voltage at the relatively non-punctuate end in secondary coil punctuate end is-VS, the relatively non-punctuate in transformer secondary coil punctuate end
The forward mutation assay voltage at end is VS, 0 < VT+ < VS of-VS < VT- <.
2. application claim 1 described in isolation transmission method circuit characterized by comprising transformer, operational amplifier,
First resistor, second resistance, 3rd resistor and the 4th resistance, a termination Transistor-Transistor Logic level signal input part of first resistor, the other end
The punctuate end of transformer is connected, the non-punctuate of transformer terminates the first signal ground, transformer secondary output line
The non-punctuate termination second signal of circle, one end of the punctuate termination second resistance of transformer secondary coil, second resistance it is another
The positive input terminal of one termination operational amplifier, the both ends of 3rd resistor connect the positive input terminal and output end of operational amplifier respectively,
The both ends of 4th resistance with connecing second signal respectively and the negative input end of operational amplifier, the output end of operational amplifier be used as every
Transistor-Transistor Logic level signal output end from after.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910275296.0A CN109951405A (en) | 2019-04-04 | 2019-04-04 | Signal-isolated transmission method and circuit based on transformer and operational amplifier |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910275296.0A CN109951405A (en) | 2019-04-04 | 2019-04-04 | Signal-isolated transmission method and circuit based on transformer and operational amplifier |
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| CN109951405A true CN109951405A (en) | 2019-06-28 |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101499647A (en) * | 2008-12-30 | 2009-08-05 | 天津理工大学 | Dual core controlled three-phase reversible converter failure diagnosis system and working method thereof |
| CN101964646A (en) * | 2010-09-30 | 2011-02-02 | 中国船舶重工集团公司第七二三研究所 | Floating grid modulator |
| CN104811183A (en) * | 2015-05-21 | 2015-07-29 | 北京联合大学 | Electric signal sampling isolation circuit |
| CN106921296A (en) * | 2017-04-20 | 2017-07-04 | 中国电子科技集团公司第四十三研究所 | A kind of transmitted in both directions magnetic isolation feedback circuit and its implementation |
-
2019
- 2019-04-04 CN CN201910275296.0A patent/CN109951405A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101499647A (en) * | 2008-12-30 | 2009-08-05 | 天津理工大学 | Dual core controlled three-phase reversible converter failure diagnosis system and working method thereof |
| CN101964646A (en) * | 2010-09-30 | 2011-02-02 | 中国船舶重工集团公司第七二三研究所 | Floating grid modulator |
| CN104811183A (en) * | 2015-05-21 | 2015-07-29 | 北京联合大学 | Electric signal sampling isolation circuit |
| CN106921296A (en) * | 2017-04-20 | 2017-07-04 | 中国电子科技集团公司第四十三研究所 | A kind of transmitted in both directions magnetic isolation feedback circuit and its implementation |
Non-Patent Citations (1)
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| 张金波等: "利用音频变压器隔离方式实现数据远程传输", 《工矿自动化》 * |
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Application publication date: 20190628 |
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