CN208860891U - A kind of current foldback circuit - Google Patents
A kind of current foldback circuit Download PDFInfo
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- CN208860891U CN208860891U CN201821575647.7U CN201821575647U CN208860891U CN 208860891 U CN208860891 U CN 208860891U CN 201821575647 U CN201821575647 U CN 201821575647U CN 208860891 U CN208860891 U CN 208860891U
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Abstract
The utility model discloses a kind of current foldback circuits; it is used to for the voltage signal being compared with reference voltage, and overcurrent protection signal is issued according to comparison result including current sampling unit, error amplifying unit, voltage follow unit, sluggish comparing unit, sluggish comparing unit；The output end of the current sampling unit connects the input terminal of the error amplifying unit, and the output end of the error amplifying unit connects the input terminal of the voltage follow unit, and the output end of the voltage follow unit connects the input terminal of the sluggish comparing unit.When input current reaches the overcurrent protection value of setting, sluggish comparing unit sends PRT and protects signal the current foldback circuit of the utility model, so that DC is entered guard mode, effectively increases overcurrent response speed, current foldback circuit compared with prior art is more stable.
Description
Technical field
The utility model relates to power technique fields, more particularly to a kind of current foldback circuit.
Background technique
In existing module Switching Power Supply, it generally can all require have overcurrent protection function, especially in New energy electric vapour
Vehicle is this to require harsher occasion.Overcurrent protection function, which is that power source internal electric current is excessive in order to prevent, causes internal component
Damage either external electric equipment damage, so that design protection circuit controls power remove, traditional overcurrent protection electricity
Road has that overcurrent corresponding speed is unstable compared with slow and circuit.
In consideration of it, it is necessary to research and develop a kind of current foldback circuit that can be improved overcurrent protection timeliness.
Utility model content
The purpose of the utility model is to overcome shortcomings in the prior art, provide a kind of current foldback circuit, have
Overcurrent protection fast response time, the more stable advantage of circuit.
The utility model is solved by following technical proposals:
A kind of current foldback circuit, comprising: current sampling unit, for obtaining current difference signal；Error amplifying unit,
For the differential signal to be amplified and amplified current signal is converted to voltage signal；Voltage follow unit is used
In the stabilization for keeping the voltage signal；Sluggish comparing unit, for the voltage signal to be compared with reference voltage, and
Overcurrent protection signal is issued according to comparison result；
The output end of the current sampling unit connects the input terminal of the error amplifying unit, the error amplifying unit
Output end connect the input terminal of the voltage follow unit, the output end connection of the voltage follow unit it is described it is sluggish relatively
The input terminal of unit.
Further, the error amplifying unit includes amplifier U1, resistance R212, resistance R213, resistance R215, resistance
R216, resistance R359, resistance R360, resistance R361, resistance R362, capacitor C117, capacitor C118, capacitor C190, diode
D52, diode D35, the resistance R215 one end simultaneously connect the current sampling unit one end and capacitor C118 one
The one end at end, the resistance R213 connects the other end of the current sampling unit and the other end of capacitor C118 simultaneously, described
The other end of resistance R215 connect capacitor C117, one end of resistance R360 and diode D52 after connecting with resistance R212 simultaneously
The other end of capacitor C117, diode D52 are connect after anode, the other end of the resistance R213 and resistance R216 series connection simultaneously
One end of cathode, resistance R359, the other end of the resistance R360 connect simultaneously the anode of diode D35, capacitor C90 one
The other end of the inverting input terminal at end, one end of resistance R362 and amplifier U1, the resistance R359 connects diode D35 simultaneously
Cathode, the other end of capacitor C90, one end of resistance R361 and amplifier U1 normal phase input end, the resistance R361's is another
One end ground connection, the output end of the other end connection amplifier U1 of the resistance R362.
Further, the sluggish comparing unit includes resistance R10, resistance R14, resistance R176, resistance R181, capacitor
C87, capacitor C88, capacitor C89, diode D59, the normal phase input end of diode D60 and amplifier U3, the amplifier U3 are logical
The output end that resistance R10 connects the voltage follow unit is crossed, the inverting input terminal of the amplifier U3 is connected by resistance R176
Reference voltage input VREF is met, the normal phase input end of one end connection amplifier U3 of capacitor C87, the other end is grounded, described to put
The output end connection protection signal output end PRT of big device U3, the output end of amplifier U3 also connect diode D59 and two poles simultaneously
The anode of pipe D60, diode D59 connect one end of resistance R181 Yu capacitor C88, capacitor C88 with the cathode of diode D60 simultaneously
Be connected to the normal phase input end of amplifier U3 with the other end of resistance R181, the resistance R14 and capacitor C89 it is in parallel after one end connect
It is connected to the inverting input terminal of amplifier U3, other end ground connection.
Further, the voltage follow unit includes resistance R357, resistance R363, capacitor C32 and amplifier U2, described
The normal phase input end of amplifier U2 connects one end of resistance R357 and resistance R263 simultaneously, and the other end of resistance R367 connects the mistake
Poor amplifying unit, resistance R357 are grounded after passing through capacitor C32, described in the connection simultaneously of the inverting input terminal and output end of amplifier U2
The input terminal of sluggish comparing unit.
Further, the current sampling unit is resistance R98 and resistance R99 parallel with one another.
The utility model have the following advantages that compared with prior art and the utility model has the advantages that
The current foldback circuit of the utility model is by current sampling unit, error amplifying unit, voltage follow unit, sluggishness
Comparing unit is constituted, and sluggish comparing unit adjusts resistance R176's and resistance R14 by being compared and passing through with reference voltage
The a reference value of sluggish comparing unit is adjusted in resistance value realization, and then adjusts overcurrent value, when input current reaches the mistake of setting
When flowing protection value, sluggish comparing unit sends PRT and protects signal, and DC is made to enter guard mode, effectively increases overcurrent response speed
Degree, current foldback circuit compared with prior art are more stable.
Detailed description of the invention
Utility model will be further described in detail below with reference to the attached drawings and specific embodiments.
Fig. 1 is a kind of principle modules figure of current foldback circuit.
Fig. 2 is a kind of circuit diagram of current foldback circuit.
Specific embodiment
The present invention will be further described in detail with reference to the embodiments and the accompanying drawings, but the implementation of the utility model
Mode is without being limited thereto.
The specific implementation process of the utility model is as follows:
As depicted in figs. 1 and 2, a kind of current foldback circuit, comprising:
Current sampling unit, for obtaining current difference signal；
Error amplifying unit, for being amplified the differential signal and amplified current signal being converted to voltage
Signal；
Voltage follow unit, for keeping the stabilization of the voltage signal；
Sluggish comparing unit for the voltage signal to be compared with reference voltage, and is issued according to comparison result
Overcurrent protection signal；
The output end of the current sampling unit connects the input terminal of the error amplifying unit, the error amplifying unit
Output end connect the input terminal of the voltage follow unit, the output end connection of the voltage follow unit it is described it is sluggish relatively
The input terminal of unit.
The error amplifying unit includes amplifier U1, resistance R212, resistance R213, resistance R215, resistance R216, resistance
R359, resistance R360, resistance R361, resistance R362, capacitor C117, capacitor C118, capacitor C190, diode D52, diode
One end of D35, the resistance R215 connect one end of the current sampling unit and one end of capacitor C118, the resistance simultaneously
One end of R213 connects the other end of the current sampling unit and the other end of capacitor C118 simultaneously, and the resistance R215's is another
One end connect the anode of capacitor C117, one end of resistance R360 and diode D52, the resistance simultaneously after connecting with resistance R212
The other end of R213 connect the other end of capacitor C117, the cathode of diode D52, resistance R359 after connecting with resistance R216 simultaneously
One end, the other end of the resistance R360 connect simultaneously the anode of diode D35, one end of capacitor C90, resistance R362 one
The inverting input terminal of end and amplifier U1, the other end of the resistance R359 connect cathode, the capacitor C90 of diode D35 simultaneously
The other end, one end of resistance R361 and the normal phase input end of amplifier U1, the resistance R361 the other end ground connection, the electricity
Hinder the output end of the other end connection amplifier U1 of R362.
The sluggishness comparing unit includes resistance R10, resistance R14, resistance R176, resistance R181, capacitor C87, capacitor
C88, capacitor C89, diode D59, diode D60 and amplifier U3, the amplifier U3 normal phase input end pass through resistance R10
The output end of the voltage follow unit is connected, the inverting input terminal of the amplifier U3 passes through resistance R176 connection reference voltage
The normal phase input end of one end connection amplifier U3 of input terminal VREF, capacitor C87, other end ground connection, the amplifier U3's is defeated
Outlet connection protection signal output end PRT, the output end of amplifier U3 are also connecting diode D59 and diode D60 just simultaneously
Pole, diode D59 connect one end of resistance R181 Yu capacitor C88, capacitor C88 and resistance with the cathode of diode D60 simultaneously
The other end of R181 is connected to the normal phase input end of amplifier U3, the resistance R14 and capacitor C89 it is in parallel after one end be connected to and put
The inverting input terminal of big device U3, other end ground connection.
The voltage follow unit includes resistance R357, resistance R363, capacitor C32 and amplifier U2, the amplifier U2
Normal phase input end connect one end of resistance R357 and resistance R263 simultaneously, it is single that the other end of resistance R367 connects the error amplification
Member, resistance R357 are grounded after passing through capacitor C32, and the inverting input terminal and output end of amplifier U2 connects the sluggishness relatively simultaneously
The input terminal of unit.
The working principle of the utility model are as follows: the current sampling unit be resistance R98 and resistance R99 parallel with one another,
For sampling to electric current in access cathode traces, current sampling unit collects the difference of resistance R98 and the both ends resistance R99
Differential signal error originated from input amplifier amplifies differential signal after signal, is then changed into amplified differential signal
Voltage signal, it should be noted that in the present embodiment, diode D52 and diode D35 are zener diode, zener diode
Protective effect can be formed to error amplifying unit, keep error amplifying unit more stable.Error amplifier is defeated by voltage signal
Enter voltage follow unit, voltage follow unit makes signal avoid noise jamming, do not influenced by late-class circuit, is able to maintain sampling letter
It is number more stable.Voltage signal is inputted the positive of amplifier U3 in sluggish comparing unit by voltage follow unit by resistance R10
Input terminal, the input terminal VREF of the inverting input terminal connection reference voltage of amplifier, by the voltage signal and reference voltage of acquisition
It is compared, it should be noted that in the present embodiment, resistance R176 and resistance R14 are adjustable resistance, by adjusting resistance R176
Overcurrent protection value is adjusted in turn with a reference value of the resistance value of resistance R14, i.e., adjustable sluggish comparing unit, when input current reaches
When the overcurrent protection value of setting, amplifier U3 overturning becomes high level and issues PRT overcurrent protection signal, so that DC enters overcurrent guarantor
Shield state.
Above-described embodiment is the preferable embodiment of the utility model, but the embodiments of the present invention is not by above-mentioned
The limitation of embodiment, it is made under other any spiritual essence and principles without departing from the utility model to change, modify, replacing
In generation, simplifies combination, should be equivalent substitute mode, is included within the protection scope of the utility model.
Claims (5)
1. a kind of current foldback circuit characterized by comprising
Current sampling unit, for obtaining current difference signal；
Error amplifying unit, for being amplified the differential signal and amplified current signal being converted to voltage letter
Number；
Voltage follow unit, for keeping the stabilization of the voltage signal；
Sluggish comparing unit issues overcurrent for the voltage signal to be compared with reference voltage, and according to comparison result
Protect signal；
The output end of the current sampling unit connects the input terminal of the error amplifying unit, the error amplifying unit it is defeated
Outlet connects the input terminal of the voltage follow unit, the output end connection of the voltage follow unit sluggish comparing unit
Input terminal.
2. a kind of current foldback circuit according to claim 1, it is characterised in that: the error amplifying unit includes amplification
Device U1, resistance R212, resistance R213, resistance R215, resistance R216, resistance R359, resistance R360, resistance R361, resistance R362,
Described in capacitor C117, capacitor C118, capacitor C190, diode D52, one end of diode D35, the resistance R215 while connection
One end of one end of current sampling unit and one end of capacitor C118, the resistance R213 connects the current sampling unit simultaneously
The other end and capacitor C118 the other end, connect capacitor simultaneously after the other end of the resistance R215 and resistance R212 series connection
The anode of C117, one end of resistance R360 and diode D52, the other end of the resistance R213 connect with resistance R216 after simultaneously
One end of the other end of capacitor C117, the cathode of diode D52, resistance R359 is connected, the other end of the resistance R360 is simultaneously
Connect the inverting input terminal of the anode of diode D35, one end of capacitor C90, one end of resistance R362 and amplifier U1, the electricity
The other end for hindering R359 connects the cathode of diode D35, the other end of capacitor C90, one end of resistance R361 and amplifier simultaneously
The normal phase input end of U1, the other end ground connection of the resistance R361, the other end connection amplifier U1's of the resistance R362 is defeated
Outlet.
3. a kind of current foldback circuit according to claim 1 or 2, it is characterised in that: it is described sluggishness comparing unit include
Resistance R10, resistance R14, resistance R176, resistance R181, capacitor C87, capacitor C88, capacitor C89, diode D59, diode D60
And amplifier U3, the normal phase input end of the amplifier U3 connect the output end of the voltage follow unit, institute by resistance R10
The inverting input terminal for stating amplifier U3 is put by one end connection of resistance R176 connection reference voltage input VREF, capacitor C87
The normal phase input end of big device U3, other end ground connection, the output end connection protection signal output end PRT of the amplifier U3, amplification
The output end of device U3 also connects the anode of diode D59 Yu diode D60 simultaneously, and diode D59 and the cathode of diode D60 are same
When connect one end of resistance R181 and capacitor C88, the positive that the other end of capacitor C88 and resistance R181 are connected to amplifier U3 is defeated
Enter end, the resistance R14 and capacitor C89 it is in parallel after one end be connected to the inverting input terminal of amplifier U3, other end ground connection.
4. a kind of current foldback circuit according to claim 3, it is characterised in that: the voltage follow unit includes resistance
R357, resistance R363, capacitor C32 and amplifier U2, the amplifier U2 normal phase input end connect resistance R357 and resistance simultaneously
One end of R263, the other end of resistance R367 connect the error amplifying unit, and resistance R357 is grounded after passing through capacitor C32, puts
The inverting input terminal and output end of big device U2 connect the input terminal of the sluggish comparing unit simultaneously.
5. a kind of according to claim 1,2,4 described in any item current foldback circuits, it is characterised in that: the current sampling list
Member is resistance R98 and resistance R99 parallel with one another.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821575647.7U CN208860891U (en) | 2018-09-27 | 2018-09-27 | A kind of current foldback circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821575647.7U CN208860891U (en) | 2018-09-27 | 2018-09-27 | A kind of current foldback circuit |
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| Publication Number | Publication Date |
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| CN208860891U true CN208860891U (en) | 2019-05-14 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201821575647.7U Active CN208860891U (en) | 2018-09-27 | 2018-09-27 | A kind of current foldback circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110369160A (en) * | 2019-06-25 | 2019-10-25 | 深圳市四方电气技术有限公司 | Centrifuge driver protects circuit |
-
2018
- 2018-09-27 CN CN201821575647.7U patent/CN208860891U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110369160A (en) * | 2019-06-25 | 2019-10-25 | 深圳市四方电气技术有限公司 | Centrifuge driver protects circuit |
| CN110369160B (en) * | 2019-06-25 | 2021-07-30 | 深圳市四方电气技术有限公司 | Centrifuge driver protection circuit |
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