CN207603267U - A kind of current-limiting control circuit - Google Patents
A kind of current-limiting control circuit Download PDFInfo
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- CN207603267U CN207603267U CN201721772621.7U CN201721772621U CN207603267U CN 207603267 U CN207603267 U CN 207603267U CN 201721772621 U CN201721772621 U CN 201721772621U CN 207603267 U CN207603267 U CN 207603267U
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- resistance
- triode
- current
- voltage
- control circuit
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Abstract
The utility model discloses a kind of current-limiting control circuit, voltage-reference U1, diode D1, resistance R1, triode Q1 and resistance R2 including being in turn connected to form closed loop；The emitter-base bandgap grading of the triode Q1 is connect with one end of resistance R2, and the collector of triode Q1 is connect with one end of resistance R1, and the base stage of triode Q1 is connected between the positive terminal of diode D1 and resistance R1；The negative pole end of the diode D1 is connected to voltage-reference U1；Voltage-reference U1 connect with resistance R2 and draws the positive terminal for being connected to VCC ends and capacitor C1；The negative pole end ground connection of capacitor C1.The utility model effectively prevents transmitter circuit (or load) and directly takes electricity that loop current is caused to export burr from 4 20mA loops.
Description
Technical field
The utility model belongs to electronic circuit technology field, is related to a kind of transmitter circuit, especially a kind of Current limited Control
Circuit.
Background technology
In the prior art, widely used 4~20mA electric currents transmit analog quantity, and the principle of two-wire system transducer is to be utilized
4~20mA signals provide electric energy for itself.If transmitter itself power consumption is more than 4mA, then would be impossible to bottoming 4mA
Value, therefore general require two-wire system transducer itself power consumption (whole circuits including sensor) this is no more than 3.5mA
One of design cardinal principle of two-wire system transducer, therefore the low-power consumption of circuit becomes main design difficulty.
However, the low-power consumption of two-wire system 4-20mA transmitter circuits requires to bring many restrictions to design, especially work as change
Device is sent using digital interface sensor or function module, when these sensors or function module periodic duty, leads to transmitter
Moment power consumption is more than bottoming value 4mA, and current spikes are formed on transmitter output ring road, and it is wrong to directly result in output result
Accidentally.
Utility model content
The purpose of the utility model is to overcome the shortcomings that the above-mentioned prior art, a kind of current-limiting control circuit is provided.
The purpose of this utility model is achieved through the following technical solutions：
A kind of current-limiting control circuit, including be in turn connected to form the voltage-reference U1 of closed loop, diode D1, resistance R1,
Triode Q1 and resistance R2；The emitter-base bandgap grading of the triode Q1 is connect with one end of resistance R2, collector and the resistance R1 of triode Q1
One end connection, the base stage of triode Q1 is connected between the positive terminal of diode D1 and resistance R1；The diode D1's is negative
Extremely it is connected to voltage-reference U1；Voltage-reference U1, which connect and drawn with resistance R2, is connected to VCC ends and capacitor C1
Positive terminal；The negative pole end ground connection of capacitor C1.
Above-mentioned triode Q1 is NPN type triode.
Above-mentioned voltage-reference U1 is both ends type voltage-reference.
The utility model has the advantages that：
The current-limiting control circuit of the utility model is to increase current limliting to the load supplying front end of two-wire system 4-20mA transmitters
Accumulator, current-limiting energy storage circuit obtain from current loop under the levels of current of permission and store electric energy, when needed to become
Device circuit (or load) is sent to provide instantaneous large-current, transmitter circuit (or load) is effectively prevented and is directly taken from 4-20mA loops
Electricity causes loop current to export burr.
Description of the drawings
Fig. 1 is the circuit connection diagram of the utility model；
Fig. 2 is the application schematic diagram of the utility model circuit.
Specific embodiment
The utility model is described in further detail below in conjunction with the accompanying drawings：
As shown in Figure 1：The current-limiting control circuit of the utility model, the voltage-reference including being in turn connected to form closed loop
U1, diode D1, resistance R1, triode Q1 and resistance R2；The emitter-base bandgap grading of triode Q1 is connect with one end of resistance R2, triode
The collector of Q1 is connect with one end of resistance R1, and the base stage of triode Q1 is connected between the positive terminal of diode D1 and resistance R1；
The negative pole end of diode D1 is connected to voltage-reference U1；Voltage-reference U1, which connect and drawn with resistance R2, is connected to VCC ends
With the positive terminal of capacitor C1；The negative pole end ground connection of capacitor C1.
The triode Q1 of the utility model is NPN type triode.Voltage-reference U1 is both ends type voltage-reference.
In the utility model circuit, capacitance C1 does energy-storage travelling wave tube use：Both ends type voltage-reference U1, diode D1, electricity
It hinders R1, resistance R2, triode Q1 and forms current-limiting circuit, realize current-limiting function；V+ is electric current loop power supply anode, and diode D1 is used for
Compensation triode Q1 causes PN junction temperature drift, resistance R1 protections voltage-reference U1, resistance R2 and voltage reference due to temperature change
Source U1 determines the size of electric current；
The current-limiting control circuit application of the utility model is as shown in Figure 2：The input of current-limiting control circuit terminates to two-wire system
The 4-20mA loop anodes of V/I translation circuits；The output terminal of current-limiting control circuit is connected to processing and modulate circuit, processing and tune
Manage the feeder ear of circuit, the storage capacitor reference edge ground connection of current-limiting control circuit.Processing and modulate circuit be connected with sensor and
Display and button.
Claims (3)
1. a kind of current-limiting control circuit, which is characterized in that voltage-reference U1, diode including being in turn connected to form closed loop
D1, resistance R1, triode Q1 and resistance R2；The emitter-base bandgap grading of the triode Q1 is connect with one end of resistance R2, the collection of triode Q1
Pole is connect with one end of resistance R1, and the base stage of triode Q1 is connected between the positive terminal of diode D1 and resistance R1；Described two
The negative pole end of pole pipe D1 is connected to voltage-reference U1；Voltage-reference U1 connect with resistance R2 and draw be connected to VCC ends and
The positive terminal of capacitor C1；The negative pole end ground connection of capacitor C1.
2. current-limiting control circuit according to claim 1, which is characterized in that the triode Q1 is NPN type triode.
3. current-limiting control circuit according to claim 1, which is characterized in that the voltage-reference U1 is both ends type voltage
A reference source.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721772621.7U CN207603267U (en) | 2017-12-19 | 2017-12-19 | A kind of current-limiting control circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721772621.7U CN207603267U (en) | 2017-12-19 | 2017-12-19 | A kind of current-limiting control circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN207603267U true CN207603267U (en) | 2018-07-10 |
Family
ID=62767108
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201721772621.7U Active CN207603267U (en) | 2017-12-19 | 2017-12-19 | A kind of current-limiting control circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN207603267U (en) |
-
2017
- 2017-12-19 CN CN201721772621.7U patent/CN207603267U/en active Active
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