CN109861511A - Current foldback circuit and Over Current Protection System - Google Patents
Current foldback circuit and Over Current Protection System Download PDFInfo
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- CN109861511A CN109861511A CN201811646441.3A CN201811646441A CN109861511A CN 109861511 A CN109861511 A CN 109861511A CN 201811646441 A CN201811646441 A CN 201811646441A CN 109861511 A CN109861511 A CN 109861511A
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- 238000005070 sampling Methods 0.000 claims abstract description 86
- 230000003321 amplification Effects 0.000 claims abstract description 45
- 238000003199 nucleic acid amplification method Methods 0.000 claims abstract description 45
- 239000003990 capacitor Substances 0.000 claims description 28
- 230000033228 biological regulation Effects 0.000 claims description 15
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
- H02H3/087—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current for dc applications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/32—Means for protecting converters other than automatic disconnection
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- Emergency Protection Circuit Devices (AREA)
Abstract
The present invention discloses a kind of current foldback circuit and Over Current Protection System; including voltage sampling module, differential amplification module, voltage comparison module and control module; two input terminals of the differential amplification module are electrically connected with the voltage sampling module respectively; the output end of the differential amplification module is electrically connected with an input terminal of the voltage comparison module; the output end of the voltage sampling module is also electrically connected with another input terminal of the voltage comparison module, and the output end of the voltage comparison module is electrically connected with the control module.The present invention is a kind of current foldback circuit and Over Current Protection System; by the way that voltage sampling module is arranged in the output end of power supply; it can make during overcurrent protection; the voltage of sampling will not be interfered by the load of output end; avoid the appearance false triggering of current foldback circuit; so that the work of the control circuit starting overcurrent protection of power supply, guarantees that printer can normally work.
Description
Technical field
The present invention relates to printer power supply fields, more particularly to a kind of current foldback circuit and Over Current Protection System.
Background technique
Many electronic equipments have a rated current, do not allow more than rated current, not so can burn out equipment.So some
Equipment has just done overcurrent protection module.When electric current is more than setting electric current, equipment is automatically powered off, to protect equipment.Such as mainboard
The usb interface of cpu generally has usb overcurrent protection, and mainboard is protected not to be burned.
In traditional printer power supply, the usually output with two-way or multichannel is the voltage that output is 40V all the way,
Another way is the voltage for exporting 22V, and for the over-current detection of this two-way or multiple-channel output, over-current detection resistance is generally required
It is placed on high-end, that is, is placed on cathode output end, does high-end detection.The reason of ground terminal detection cannot be done be multiple-channel output altogether, if
If all putting ground terminal per over-current detection resistance all the way, it can all participate in shunting per ground terminal all the way, be that can not achieve accurately mistake
Stream detection.When the load of the two output institute's bands is different, if the load regulation of power supply is not good enough, it will also tend to
The output voltage for influencing two-way is then likely to so that traditional being triggered for current foldback circuit starts overcurrent protection, this
There have been the false triggerings of overcurrent protection, so that chip is also triggered protection in the power supply, prevent power supply is from continuing work
Make, influences the use of printer.If also, the output end of 40V voltage and 20V voltage output end institute band load it is different if,
Also the precision for influencing whether current foldback circuit sampling, to the case where overcurrent protection is by false triggering may also occur.
Summary of the invention
The purpose of the present invention is overcoming shortcoming in the prior art, one kind is provided and more accurately samples, avoid the occurrence of
The current foldback circuit and Over Current Protection System of false triggering.
The purpose of the present invention is achieved through the following technical solutions:
A kind of current foldback circuit, comprising: voltage sampling module, differential amplification module, voltage comparison module and control mould
Two input terminals of block, the differential amplification module are electrically connected with the voltage sampling module respectively, the differential amplification module
Output end be electrically connected with an input terminal of the voltage comparison module, the output end of the voltage sampling module also with the electricity
Another input terminal electrical connection of comparison module is pressed, the output end of the voltage comparison module is electrically connected with the control module.
The voltage sampling module includes sample resistance R202 in one of the embodiments, the sample resistance R202
First end be electrically connected with the first input end of the differential amplification module, the second end of the sample resistance R202 and the difference
Divide the second input terminal electrical connection of amplification module.
The differential amplification module includes differential amplification unit, the first sampling unit and in one of the embodiments,
Two sampling units, the input terminal of first sampling unit are connect with the first end of the voltage sampling module, and described first takes
The output end of sample unit is electrically connected with the inverting input terminal of the differential amplification unit, the input terminal of second sampling unit with
The second end of the voltage sampling module connects, the output end and the same phase of the differential amplification unit of second sampling unit
Input terminal electrical connection, the output end of the differential amplification unit are electrically connected with the voltage comparison module.
The differential amplification unit includes amplifier U602B in one of the embodiments, the amplifier U602B's
Non-inverting input terminal is electrically connected with the output end of second sampling unit, the inverting input terminal of the amplifier U602B with it is described
The output end of first sampling unit is electrically connected, the output end of the amplifier U602B and the input terminal of the voltage comparison module
Electrical connection.
The voltage comparison module includes that voltage comparison unit, voltage regulation unit and partial pressure are single in one of the embodiments,
Member, the input terminal of the partial pressure unit are electrically connected with the output end of the voltage sampling module, the output end of the partial pressure unit
It is electrically connected with the inverting input terminal of the voltage comparison unit, the both ends of the both ends of the voltage regulation unit and the partial pressure unit are simultaneously
Connection connection, the non-inverting input terminal of the voltage comparison unit are electrically connected with the output end of the differential amplification module, the voltage
The output end of comparing unit is exported into the control module.
The voltage comparison unit includes comparator U602A and diode D606, the ratio in one of the embodiments,
Non-inverting input terminal compared with device U602A is electrically connected with the output end of the differential amplification module, and the reverse phase of the comparator U602A is defeated
Enter end to be electrically connected with the output end of the partial pressure unit, the sun of the output end of the comparator U602A and the diode D606
Pole electrical connection, the cathode of the diode D606 are electrically connected with the input terminal of the control module.
The voltage comparison module further includes current limliting filter unit in one of the embodiments, and the current limliting filtering is single
The input terminal of member is electrically connected with the output end of the voltage sampling module, the output end of the current limliting filter unit and the partial pressure
The input terminal of unit is electrically connected.
The current limliting filter unit includes current-limiting resistance R637 and filter capacitor C613, institute in one of the embodiments,
The first end for stating current-limiting resistance R637 is electrically connected with the output end of the voltage sampling module, and the second of the current-limiting resistance R637
End is electrically connected with the input terminal of the partial pressure unit, and the of the first end of the filter capacitor C613 and the current-limiting resistance R637
One end electrical connection, the second end of the filter capacitor C613 are electrically connected with the negative terminal of the voltage comparison unit.
The control module includes control circuit and optocoupler unit in one of the embodiments, the optocoupler unit
Input terminal is electrically connected with the input terminal of the voltage comparison module, the output end of the optocoupler unit and the control of the control circuit
End electrical connection processed.
The present invention also provides a kind of Over Current Protection Systems, including current foldback circuit described in any of the above one.
The present invention compared with the prior art the advantages of and have the beneficial effect that:
The present invention is a kind of current foldback circuit and Over Current Protection System, is taken by the way that voltage is arranged in the output end of power supply
Egf block can make during overcurrent protection, and the voltage of sampling will not be each to export by two-way or multiple-channel output regulation
With the influence for carrying size cases.The appearance false triggering of current foldback circuit is avoided, so that the control circuit starting overcurrent of power supply is protected
The work of shield guarantees that printer can normally work.
Detailed description of the invention
In order to illustrate the technical solution of the embodiments of the present invention more clearly, below will be to needed in the embodiment attached
Figure is briefly described, it should be understood that the following drawings illustrates only certain embodiments of the present invention, therefore is not construed as pair
The restriction of range for those of ordinary skill in the art without creative efforts, can also be according to this
A little attached drawings obtain other relevant attached drawings.
Fig. 1 is the functional block diagram of the current foldback circuit of an embodiment of the present invention；
Fig. 2 is the circuit diagram of the voltage sampling module of the output end of Over Current Protection System shown in FIG. 1；
Fig. 3 is the circuit diagram of the control module of current foldback circuit shown in FIG. 1；
Fig. 4 is the circuit diagram of current foldback circuit shown in FIG. 1；
Fig. 5 is the functional block diagram of the delay protection circuit of the Over Current Protection System of an embodiment of the present invention；
Fig. 6 is the circuit diagram of the delay protection circuit of Over Current Protection System shown in Fig. 4.
Specific embodiment
To facilitate the understanding of the present invention, a more comprehensive description of the invention is given in the following sections with reference to the relevant attached drawings.In attached drawing
Give better embodiment of the invention.But the invention can be realized in many different forms, however it is not limited to herein
Described embodiment.On the contrary, the purpose of providing these embodiments is that making to understand more the disclosure
Add thorough and comprehensive.
It should be noted that it can directly on the other element when element is referred to as " being fixed on " another element
Or there may also be elements placed in the middle.When an element is considered as " connection " another element, it, which can be, is directly connected to
To another element or it may be simultaneously present centering elements.Term as used herein " vertical ", " horizontal ", " left side ",
" right side " and similar statement for illustrative purposes only, are not meant to be the only embodiment.
Unless otherwise defined, all technical and scientific terms used herein and belong to technical field of the invention
The normally understood meaning of technical staff is identical.Term as used herein in the specification of the present invention is intended merely to description tool
The purpose of the embodiment of body, it is not intended that in the limitation present invention.Term " and or " used herein includes one or more
Any and all combinations of relevant listed item.
Referring to Fig. 1, a kind of current foldback circuit, comprising: voltage sampling module 100, differential amplification module 200, voltage
Comparison module 300 and control module 400, two input terminals of the differential amplification module 200 respectively with the voltage sampling mould
Block 100 is electrically connected, and the output end of the differential amplification module 200 is electrically connected with an input terminal of the voltage comparison module 300,
The output end of the voltage sampling module 100 is also electrically connected with another input terminal of the voltage comparison module 300, the voltage
The output end of comparison module 300 is electrically connected with the control module 400.It should be noted that the voltage sampling module 100 is used
In the voltage for obtaining power output end；The differential amplification module 200 is used to obtain the voltage at voltage sampling module both ends, and passes through
Output is into an input terminal of the voltage comparison module 300 after the circuit of itself, then by exporting with voltage sampling module
After voltage is compared, by the output of voltage comparison module 300 into control module；The control module 400 is for realizing power supply
Overcurrent protection.
In this way, can be made during overcurrent protection by the way that voltage sampling module is arranged in the output end of power supply,
The voltage of sampling will not be interfered by the load of output end, avoid the appearance false triggering of current foldback circuit, so that the control of power supply
The work of circuit start overcurrent protection processed guarantees that printer can normally work.
It should be noted that referring to Fig. 2, the voltage sampling module includes sample resistance R202, the sample resistance
The first end of R202 is electrically connected with the first input end of the differential amplification module, the second end of the sample resistance R202 and institute
State the second input terminal electrical connection of differential amplification module.By be arranged sample resistance, the voltage of available power output end, from
And it can detecte the size of current of power output end.
It should be noted that the differential amplification module includes differential amplification unit, the first sampling unit and the second sampling
Unit, the input terminal of first sampling unit are connect with the first end of the voltage sampling module, first sampling unit
Output end be electrically connected with the inverting input terminal of the differential amplification unit, the input terminal of second sampling unit and the electricity
Press the second end connection of sampling module, the output end of second sampling unit and the non-inverting input terminal of the differential amplification unit
Electrical connection, the output end of the differential amplification unit are electrically connected with the voltage comparison module.First sampling unit is used for
The first voltage 40V-2 of the side sample resistance R202 is obtained, second sampling unit is another for obtaining sample resistance R202
The second voltage 40V of side, then two obtained voltage transmissions will be sampled into differential amplification unit, if the pressure difference of the two voltages
It is linear increase if, then the voltage of the output end of differential amplification unit also will appear linear raising, then raised voltage
It is transmitted in voltage comparison module again.
Specifically, referring to Fig. 3, the differential amplification unit includes amplifier U602B, the amplifier U602B's is same
Phase input terminal is electrically connected with the output end of second sampling unit, the inverting input terminal of the amplifier U602B and described the
The output end of one sampling unit is electrically connected, the output end of the amplifier U602B and the input terminal electricity of the voltage comparison module
Connection.The amplifier U602B is used to amplify the voltage of two input terminals.
Specifically, first sampling unit includes resistance R629 and resistance R630, the first end of the resistance R629 with
The first end of the sample resistance R202 is electrically connected, and the second end of the resistance R629 is same mutually defeated with the amplifier U602B's
Enter end electrical connection, the both ends of the resistance R630 and the both ends of the resistance R629 are connected in parallel.
Specifically, second sampling unit includes capacitor C616 and resistance R623, the first end of the resistance R623 with
The second end of the sample resistance R202 is electrically connected, the second end of resistance R623 one end with the capacitor C616 respectively,
And the second end of the resistance R623 is directly electrically connected with the inverting input terminal of the amplifier U602B.Generally, in order to wait until
Higher detection accuracy, resistance R629 should be equal with the resistance value of resistance R623 with the parallel resistance value of resistance R630, resistance
R622 should be equal with the resistance value of resistance R633, and resistance R634 should be equal with the resistance value of resistance R635.So that taking
The voltage of sample is not influenced by other factors.
It should be noted that the voltage comparison module includes voltage comparison unit, voltage regulation unit and partial pressure unit, it is described
The input terminal of partial pressure unit is electrically connected with the output end of the voltage sampling module, the output end of the partial pressure unit and the electricity
The inverting input terminal electrical connection of comparing unit is pressed, the both ends of the voltage regulation unit and the both ends of the partial pressure unit are connected in parallel,
The non-inverting input terminal of the voltage comparison unit is electrically connected with the output end of the differential amplification module, the voltage comparison unit
Output end export into the control module.
Specifically, the voltage comparison unit includes comparator U602A and diode D606, the comparator U602A's
Non-inverting input terminal is electrically connected with the output end of the differential amplification module, the inverting input terminal of the comparator U602A with it is described
The output end of partial pressure unit is electrically connected, and the output end of the comparator U602A is electrically connected with the anode of the diode D606, institute
The cathode for stating diode D606 is electrically connected with the input terminal of the control module.
During the work time, in voltage comparison module, by being provided with voltage regulation unit and partial pressure unit, and list is divided
The voltage input end of member also comes from voltage sampling module, i.e., the output voltage of 40V-2 in figure, so that being input to comparator
The voltage of the inverting input terminal of U602A is remained unchanged by starting from eventually substantially.Since the voltage of the output end of amplifier U602B can be with
The first sampling unit first voltage 40V-2 and the second sampling unit second voltage 40V pressure difference increase and increase, make
The non-inverting input terminal voltage that comparator U602A must be input to also becomes larger, when the non-inverting input terminal of comparator U602A compares anti-phase input
When the voltage at end is big, i.e., when the output voltage difference of 40V-2 and 40V is greater than 0.15V in figure, then it can make comparator U602A
A high level is exported, then is transferred in control module, the overcurrent protection function of trigger control module.
Specifically, the partial pressure unit includes resistance R619 and resistance R620, the first end of the resistance R619 with it is described
The output end of voltage sampling module is electrically connected, the second end of the resistance R619 respectively with one end of the resistance R620 and described
The inverting input terminal of comparator U602A is electrically connected.In this way, by setting resistance R619 and resistance R620, and to the two resistance
It carries out setting specific parameter value, so that the voltage exported from voltage sampling module is divided by resistance R619 and resistance R620
Afterwards, keep a constant voltage (for example, the inverting input terminal that this voltage is input to comparator U602A as 2.5V) can be set
In, the two resistance mainly play the role of partial pressure.
Specifically, the voltage regulation unit includes zener diode ZD604, the cathode of the zener diode ZD604 and institute
The first end electrical connection of resistance R619 is stated, the anode of the zener diode ZD604 and the other end of the resistance R620 are electrically connected
It connects.In this way, can be kept defeated by setting zener diode ZD604 (for example using the metastable 6.2V voltage-stabiliser tube of characteristic)
The voltage entered to the inverting input terminal of comparator U602A is more stable.
It should also be noted that, the voltage comparison module further includes current limliting filter unit, the current limliting filter unit
Input terminal is electrically connected with the output end of the voltage sampling module, the output end of the current limliting filter unit and the partial pressure unit
Input terminal electrical connection.
Specifically, the current limliting filter unit includes current-limiting resistance R637 and filter capacitor C613, the current-limiting resistance
The first end of R637 is electrically connected with the output end of the voltage sampling module, the second end of the current-limiting resistance R637 with described point
The input terminal electrical connection of unit is pressed, the first end of the filter capacitor C613 and the first end of the current-limiting resistance R637 are electrically connected
It connects, the second end of the filter capacitor C613 is electrically connected with the negative terminal of the voltage comparison unit.In this way, passing through setting current limliting electricity
R637 and filter capacitor C613 is hindered, the interference for being input to the voltage of comparator U602A can be filtered out, improve the stabilization of voltage input
Property.
It should be noted that referring to Fig. 4, the control module includes control circuit and optocoupler unit, the optocoupler list
The input terminal of member is electrically connected with the input terminal of the voltage comparison module, the output end of the optocoupler unit and the control circuit
Control terminal electrical connection.In the present embodiment, there is control chip U100, the control chip is in the control circuit
U100, and using the control chip of model NCP1399A.
Specifically, the optocoupler unit includes resistance R610, resistance R100, LED P C1A and optocoupler triode
The first end of PC1B, the resistance R610 are electrically connected with the input terminal of the voltage comparison module, and the second of the resistance R610
The anode of end and the LED P C1A are electrically connected, and the LED P C1A and the optocoupler triode PC1B are electrically connected
It connects, the collector of the optocoupler triode PC1B is electrically connected with one end of the resistance R100, the other end of the resistance R100
For connecting external VCC2, and the emitter of the optocoupler triode PC1B is electrically connected with the OVP pin of the control circuit.
During the work time, as the second voltage 40V of the first voltage 40V-2 of the first sampling unit and the second sampling unit
Pressure difference be greater than 0.15V when, then can trigger comparator U602A output end output HIGH voltage so that output high voltage
It is transmitted to after zener diode ZD606 in the anode of LED P C1A, so that the conducting of optocoupler unit, i.e. optocoupler
Triode PC1B conducting, so that VCC2 is exported from the emitter of optocoupler triode PC1B to the OVP/OTP of control circuit U100
In pin, to trigger overcurrent protection function.
The present invention also provides a kind of Over Current Protection Systems, including current foldback circuit and delay protection circuit；Wherein, in order to
The function of realizing output end delay protection, improves the reliability and stability of Over Current Protection System, for example, in an embodiment
In, referring to Fig. 5, the delay protection circuit includes that anode sampling module 500, the first comparison module 600 and second compare mould
Block 700, the input terminal of the anode sampling module with voltage output end for being electrically connected, the output end of the anode sampling module
It is electrically connected with the input terminal of first comparison module, the output end of first comparison module and second comparison module
Input terminal electrical connection, the output end of second comparison module are electrically connected with the control module.It should be noted that it is described just
End sampling module is used to obtain the high-end voltage of power output end, the i.e. voltage of output plus terminal；First comparison module is used for
The voltage at anode sampling module both ends is obtained, and is exported after the circuit of itself to an input terminal of second comparison module
In, it is exported by the second comparison module into control module；The control module for realizing power supply overcurrent protection.Described second
Comparison module is time delay module.
Referring to Fig. 2, the anode sampling module 500 includes the of resistance R212 and resistance R213, the resistance R212
One end is used to be electrically connected with the anode of power output end, the second end of the resistance R212 and first comparison module 600
Input terminal electrical connection, the both ends of the resistance R213 are electrically connected with the both ends of the resistance R212 respectively, and the resistance
The first end of R212 is the sampling end of 22V-1, and the second end of the resistance R212 is the sampling end of 22V-2.In this way, by electricity
High-end voltage is taken in the output plus terminal in source, can to avoid the influence shunted due to the load bring ground terminal of multiple-channel output,
The precision of over-current detection, the i.e. precision of overcurrent sample can be improved by the way that high-end sample resistance R212 and resistance R213 is arranged,
So that the voltage of sampling will not be interfered by the load of output end during overcurrent protection, overcurrent is avoided to protect
The appearance false triggering of protection circuit, so that the work of the control circuit starting overcurrent protection of power supply, guarantees that printer can be normal
Work.
First comparison module 600 includes voltage voltage regulation unit, the first partial pressure unit, voltage input unit and the first ratio
Compared with device 600A, the input terminal of the voltage voltage regulation unit is electrically connected with the second end of the resistance R212, the voltage pressure stabilizing list
Member is electrically connected with first partial pressure unit, the voltage input unit respectively, the output end of first partial pressure unit and institute
State the inverting input terminal electrical connection of first comparator, the of another input terminal of the voltage input unit and the resistance R212
One end electrical connection, the output end of the voltage input unit is electrically connected with the non-inverting input terminal of the first comparator, and described the
The output end of one comparator is electrically connected with the input terminal of second comparison module 700.In this way, passing through setting voltage voltage regulation unit
The voltage for the inverting input terminal for being input to first comparator can be made to be stored in a fixed voltage value, first partial pressure is single
Member for realizing partial pressure function, the voltage input unit by resistance R212 first end sampling, be input to the first ratio
Compared with the non-inverting input terminal of device, and after being compared with voltage fixed value, amplify output voltage.
Specifically, referring to Fig. 6, the voltage voltage regulation unit includes Integrated circuit IC 600, the Integrated circuit IC 600
It is electrically connected respectively with the output end of the second end of the resistance R212 and first partial pressure unit.The first partial pressure unit packet
Resistance R601 and resistance R603 are included, the first end of the resistance R601 is electrically connected with one end of the Integrated circuit IC 600, described
The second end of resistance R601 is electrically connected with the first end of the resistance R603, the second end of the resistance R603 and the integrated electricity
The other end of road IC600 is electrically connected, and the first end of the resistance R601 is electrically connected with 2 feet of the first comparator U600A.Institute
Stating voltage input unit includes resistance R602, resistance R604 and resistance R611, one end of the resistance R602 and the integrated electricity
One end of road IC600 is electrically connected, and the other end of the resistance R602 is electrically connected with the resistance R604 and the resistance R611 respectively
Connect, the resistance R604 is also electrically connected with the first end of the resistance R212, the resistance R611 also with the first comparator
Non-inverting input terminal electrical connection.
Second comparison module 700 include discharge cell, delay unit, the second partial pressure unit, voltage compression limiter and
Second comparator U600B, the discharge cell, the delay unit and second partial pressure unit are respectively compared with described first
The output end of module 600 is electrically connected, the output end and the second comparator U600B of the discharge cell, the delay unit
Non-inverting input terminal electrical connection, the inverting input terminal of the output end of second partial pressure unit and the second comparator U600B
Electrical connection, the output end of the second comparator U600B are electrically connected with the control module.In this way, by setting delay unit,
Current foldback circuit can be made to have the function of delay, so that when power output end needs to carry out overcurrent protection,
It will not be protected immediately, first just can start overcurrent protection function by delay 6s~7s；The discharge cell is single for realizing delay
The electric discharge of member；Second partial pressure unit is for realizing partial pressure；The voltage compression limiter is used to limit the electricity of the second comparator
Pressure is no more than 32V, avoids the pressure difference of voltage is excessive from burning out comparator, plays the role of protection；The second comparator U600B is used
In the voltage by comparing non-inverting input terminal and inverting input terminal, and then output voltage realizes overcurrent protection into control module
Function.
Specifically, referring to Fig. 6, the delay unit includes capacitor C603, capacitor C604, resistance R607 and resistance
R627, one end of the capacitor C603 are electrically connected with the output end of the first comparator U600A, and the capacitor C603's is another
End is electrically connected with the second end of the resistance R212, and the output end of the capacitor C604 and the first comparator U600A are electrically connected
Connect, the other end of the capacitor C604 is electrically connected with the second end of the resistance R212, one end of the resistance R607 with it is described
The voltage output end of 40V-2 is electrically connected, and the other end of the resistance R607 is electric with the capacitor C604 after the resistance R627
Connection, and the resistance R627 is also electrically connected with 5 feet of the second comparator U600B；In this way, working as first comparator
When the output end of U600A exports high level, 40V-2 can be by passing through resistance R607 and resistance R627 to capacitor C603, electricity
Hold C604 to charge, in the non-inverting input terminal of obtained voltage input to the second comparator U600B.
The discharge cell includes the anode and the capacitor of diode D601 and resistance R626, the diode D601
C603 electrical connection, the cathode of the diode D601 are electrically connected after the resistance R626 with the voltage output end of the 40V-2.
In this way, system has also carried out overcurrent protection after capacitor C603 and capacitor C604 fully charged, so that it is disconnected the power supply of system,
To which the voltage of capacitor C603 and capacitor C604 will realize the function of electric discharge by diode D601 and resistance R626, for again
It carries out delay overcurrent protection and preparation is provided.
Second partial pressure unit include resistance R609 and resistance R608, the resistance R609 first end and the 40V-
2 voltage output end electrical connection, the second end of the resistance R609 respectively with the resistance R608 and second comparator
The inverting input terminal of U600B is electrically connected, in this way, the function of partial pressure may be implemented, and the second comparator is input to after partial pressure
In U600B.
The voltage compression limiter includes diode ZD601 and capacitor C605, the anode of the diode ZD601 with it is described
The second end of resistance R212 is electrically connected, i.e. voltage of the second end of resistance R212 for 22V-2, the cathode of the diode ZD601
It is electrically connected respectively with the anode connection terminal of the voltage output end of the 40V and the second comparator U600B, the capacitor C605
One end be electrically connected with the anode of the diode ZD601, the cathode of one end of the capacitor C605 and the diode ZD601
Electrical connection.In this way, after electricity under system, if the band of 22V output at this time is fully loaded, 40V output no-load, then when power supply is opened and closed
It waits, the voltage of 22V-2 may drop to the voltage close to 0V soon, and at this time if the voltage of 40V is because unloaded, power down is compared
Slowly, if its power down when also greater than 32V or more, can make second to compare when the voltage of 22V drops to 0V
Device U600B damage.Therefore after passing through setting diode ZD601, the operating voltage for being input to the second comparator U600B can be made
Clamper is in the voltage range of its safety, for example, guaranteeing the normal work of the second comparator U600B in 24V.
The present invention compared with the prior art the advantages of and have the beneficial effect that:
The present invention is a kind of current foldback circuit and Over Current Protection System, is taken by the way that voltage is arranged in the output end of power supply
Egf block can make during overcurrent protection, and the voltage of sampling will not be each to export by two-way or multiple-channel output regulation
With the influence for carrying size cases.The appearance false triggering of current foldback circuit is avoided, so that the control circuit starting overcurrent of power supply is protected
The work of shield guarantees that printer can normally work.It is suitable for output voltage is higher than the voltage application of 32V, solution
It has determined because the maximum working voltage of operational amplifier or comparator only has the shortcomings that 32V.
Only several embodiments of the present invention are expressed for embodiment described above, and the description thereof is more specific and detailed, but
It cannot be construed as a limitation to the scope of the present invention.It should be pointed out that for the ordinary skill people of this field
For member, without departing from the inventive concept of the premise, various modifications and improvements can be made, these belong to of the invention
Protection scope.Therefore, the scope of protection of the patent of the invention shall be subject to the appended claims.
Claims (10)
1. a kind of current foldback circuit characterized by comprising voltage sampling module, differential amplification module, voltage comparison module
And control module, two input terminals of the differential amplification module are electrically connected with the voltage sampling module respectively, the difference
The output end of amplification module is electrically connected with an input terminal of the voltage comparison module, and the output end of the voltage sampling module is also
It is electrically connected with another input terminal of the voltage comparison module, the output end of the voltage comparison module and control module electricity
Connection.
2. current foldback circuit according to claim 1, which is characterized in that the voltage sampling module includes sample resistance
R202, the first end of the sample resistance R202 are electrically connected with the first input end of the differential amplification module, the sampling electricity
The second end of resistance R202 is electrically connected with the second input terminal of the differential amplification module.
3. current foldback circuit according to claim 1, which is characterized in that the differential amplification module includes differential amplification
Unit, the first sampling unit and the second sampling unit, the input terminal of first sampling unit and the voltage sampling module
First end connection, the output end of first sampling unit is electrically connected with the inverting input terminal of the differential amplification unit, described
The input terminal of second sampling unit is connect with the second end of the voltage sampling module, the output end of second sampling unit with
The non-inverting input terminal of the differential amplification unit is electrically connected, the output end of the differential amplification unit and the voltage comparison module
Electrical connection.
4. current foldback circuit according to claim 3, which is characterized in that the differential amplification unit includes amplifier
U602B, the non-inverting input terminal of the amplifier U602B are electrically connected with the output end of second sampling unit, the amplifier
The inverting input terminal of U602B is electrically connected with the output end of first sampling unit, the output end of the amplifier U602B and institute
State the input terminal electrical connection of voltage comparison module.
5. current foldback circuit according to claim 1, which is characterized in that the voltage comparison module includes that voltage compares
Unit, voltage regulation unit and partial pressure unit, the input terminal of the partial pressure unit are electrically connected with the output end of the voltage sampling module,
The output end of the partial pressure unit is electrically connected with the inverting input terminal of the voltage comparison unit, the both ends of the voltage regulation unit with
The both ends of the partial pressure unit are connected in parallel, and the non-inverting input terminal of the voltage comparison unit is defeated with the differential amplification module
Outlet electrical connection, the output end of the voltage comparison unit are exported into the control module.
6. current foldback circuit according to claim 5, which is characterized in that the voltage comparison unit includes comparator
U602A and diode D606, the non-inverting input terminal of the comparator U602A and the output end of the differential amplification module are electrically connected
It connects, the inverting input terminal of the comparator U602A is electrically connected with the output end of the partial pressure unit, the comparator U602A's
Output end is electrically connected with the anode of the diode D606, the cathode of the diode D606 and the input terminal of the control module
Electrical connection.
7. current foldback circuit according to claim 5, which is characterized in that the voltage comparison module further includes current limliting filter
Wave unit, the input terminal of the current limliting filter unit are electrically connected with the output end of the voltage sampling module, the current limliting filtering
The output end of unit is electrically connected with the input terminal of the partial pressure unit.
8. current foldback circuit according to claim 7, which is characterized in that the current limliting filter unit includes current-limiting resistance
R637 and filter capacitor C613, the first end of the current-limiting resistance R637 are electrically connected with the output end of the voltage sampling module,
The second end of the current-limiting resistance R637 is electrically connected with the input terminal of the partial pressure unit, the first end of the filter capacitor C613
It is electrically connected with the first end of the current-limiting resistance R637, second end and the voltage comparison unit of the filter capacitor C613
Negative terminal electrical connection.
9. current foldback circuit according to claim 1, which is characterized in that the control module includes control circuit and light
The input terminal of coupling unit, the optocoupler unit is electrically connected with the input terminal of the voltage comparison module, the optocoupler unit it is defeated
Outlet is electrically connected with the control terminal of the control circuit.
10. a kind of Over Current Protection System, which is characterized in that including the electricity of overcurrent protection described in any one of claim 1~9
Road.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811646441.3A CN109861511A (en) | 2018-12-30 | 2018-12-30 | Current foldback circuit and Over Current Protection System |
| PCT/CN2019/121352 WO2020140656A1 (en) | 2018-12-30 | 2019-11-27 | Overcurrent protection circuit, and overcurrent protection system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811646441.3A CN109861511A (en) | 2018-12-30 | 2018-12-30 | Current foldback circuit and Over Current Protection System |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN109861511A true CN109861511A (en) | 2019-06-07 |
Family
ID=66893675
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811646441.3A Pending CN109861511A (en) | 2018-12-30 | 2018-12-30 | Current foldback circuit and Over Current Protection System |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN109861511A (en) |
| WO (1) | WO2020140656A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2020140656A1 (en) * | 2018-12-30 | 2020-07-09 | 惠州三华工业有限公司 | Overcurrent protection circuit, and overcurrent protection system |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116667268A (en) * | 2022-12-15 | 2023-08-29 | 荣耀终端有限公司 | Method for preventing triggering over-current protection and electronic equipment |
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| Publication number | Publication date |
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| WO2020140656A1 (en) | 2020-07-09 |
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Effective date of registration: 20190819 Address after: 516006 14 Districts of Zhongkai High-tech Development Zone, Huizhou City, Guangdong Province Applicant after: Huizhou Sanhua Industrial Ltd. Address before: 516006 Guangdong province Huizhou City Zhongkai high tech Development Zone Applicant before: Huizhou Huake Electrical Appliance Co. Ltd. |