CN107909972A - Current foldback circuit and method - Google Patents
Current foldback circuit and method Download PDFInfo
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- CN107909972A CN107909972A CN201711127971.2A CN201711127971A CN107909972A CN 107909972 A CN107909972 A CN 107909972A CN 201711127971 A CN201711127971 A CN 201711127971A CN 107909972 A CN107909972 A CN 107909972A
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2330/00—Aspects of power supply; Aspects of display protection and defect management
- G09G2330/04—Display protection
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- Crystallography & Structural Chemistry (AREA)
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- Theoretical Computer Science (AREA)
- Control Of Indicators Other Than Cathode Ray Tubes (AREA)
Abstract
The invention discloses a kind of current foldback circuit and method, and applied to the drive circuit of liquid crystal panel, drive circuit includes sequential control circuit, level translator and GOA circuits, and sequential control circuit and level translator is electrically connected in current foldback circuit；Current foldback circuit includes：Switch element, is electrically connected the voltage output end of mirror current source, the voltage output end of sequential control circuit and level translator；Mirror current source, is electrically connected the first end of charging capacitor, the second end ground connection of charging capacitor；Voltage comparator, first input end are electrically connected at the common port between mirror current source and the first end of charging capacitor, and the second input terminal is used to receive overcurrent protection threshold voltage, and output terminal lotus root is connected to the input terminal of level translator.The present invention solves the deficiencies in the prior art, realizes overcurrent protection and prevents false triggering overcurrent protection.
Description
Technical field
The present invention relates to technical field of liquid crystal display, more particularly, to a kind of mistake of the drive circuit applied to liquid crystal panel
Stream protection circuit and method.
Background technology
With the development of photoelectricity and semiconductor technology, panel display is also flourished.In many Display panels
In device, there is the thin film transistor (TFT) of the advantageous characteristics such as high spatial utilization ratio, low consumpting power, radiationless and low EMI
Liquid crystal display (Thin Film Transistor Liquid Crystal Display, TFT-LCD), has recently become city
The mainstream of field.Since TFT-LCD is widely used in laptop, mobile phone and TV etc. and closely bound up electronic product of living
In, requirement of the people for picture quality is higher and higher, thus the improvement of picture quality is also persistently chased after as association area always
The target asked.
Array base palte row drives (Gate Driver on Array, abbreviation GOA) technology, is to utilize existing TFT-LCD gusts
Grid (Gate) horizontal drive circuit is produced on array base palte by row (Array) processing procedure, realizes the driving to grid progressive scan
One technology of mode.Since GOA circuits can be directly made in around liquid crystal panel, making technology is simplified, but also can drop
Low product cost, improves the integrated level of liquid crystal panel, makes panel be intended to more be thinned.
With reference to figure 1, the drive circuit schematic diagram of available liquid crystal panel.The drive circuit includes sequential control circuit 11, electricity
Flat turn parallel operation 12 and GOA circuits 13, GOA circuits 13 connect each row grid line of liquid crystal panel；Sequential control circuit (TCON) 11 will
After the video frequency signal processing of input, it is converted into driving the signal of liquid crystal panel；Level translator (Level Shifter) 12 from
11 receiving voltage input signal CLK_IN of sequential control circuit (TCON), according to the voltage input signal CLK_IN received to
13 output voltage of GOA circuits output signal CLK_OUT, GOA circuit 13 is controlled according to the voltage output signal CLK_OUT received
The opening and closing of the TFT of liquid crystal panel, driving liquid crystal panel show image.
For the existing liquid crystal panel based on GOA circuits, due to some processing procedure reasons, level conversion may be made
The voltage output signal CLK_OUT output short-circuits of device, short circuit easily cause electric current increase.Excessive electric current can cause liquid crystal panel temperature
Degree is raised, burnt out, even causing fire.The output overcurrent protection (OCP) of level translator at present, is substantially and passes through detecting
The peak value (Peak) of electric current, i.e., at a time current value exceeds trigger protection after given threshold.But since voltage output is believed
Big peak point current often occurs in number CLK_OUT when voltage conversion, can so give the detecting of actual overcurrent bring
Difficulty is even detected by mistake.
Therefore, the existing overcurrent protection mode for solving the liquid crystal panel based on GOA circuits has much room for improvement and develops.
The content of the invention
It is an object of the present invention to provide a kind of current foldback circuit and method, solves the deficiencies in the prior art, realized
Stream is protected and prevents false triggering overcurrent protection.
To achieve the above object, the present invention provides a kind of current foldback circuit, applied to the drive circuit of liquid crystal panel,
The drive circuit further includes sequential control circuit, level translator and GOA circuits；The input terminal of the sequential control circuit
Receive vision signal, output terminal output voltage input signal；The level translator input terminal receives the voltage input signal,
Output terminal output voltage exports signal；The GOA circuit input ends receive the voltage output signal, output terminal connection liquid crystal surface
Each row grid line of plate；The sequential control circuit and the level translator is electrically connected in the current foldback circuit；
The current foldback circuit includes switch element, mirror current source, charging capacitor and voltage comparator；The switch element,
The voltage of the mirror current source, the voltage output end of the sequential control circuit and the level translator is electrically connected
Output terminal, the voltage input signal for the voltage output end output that the switch element is used to receive the sequential control circuit is with even
Lead to the voltage output end of the mirror current source and the level translator, export the voltage output end of the level translator
Voltage output signal corresponding with the voltage input signal is to the mirror current source；The mirror current source, is electrically connected
The first end of the charging capacitor, the second end ground connection of the charging capacitor, the mirror current source are used for described in duplication in real time
Voltage output signal charges to the charging capacitor；The voltage comparator, first input end are electrically connected at the mirror image electricity
Common port between the first end of stream source and the charging capacitor, the second input terminal is used to receive overcurrent protection threshold voltage, defeated
Outlet lotus root is connected to the input terminal of the level translator, and the voltage that the voltage comparator is used on the charging capacitor is more than
Output overcurrent protection signal during the overcurrent protection threshold voltage, to close the level translator.
To achieve the above object, present invention also offers a kind of over-current protection method, the driving electricity applied to liquid crystal panel
Road, the drive circuit further include sequential control circuit, level translator and GOA circuits；The sequential control circuit it is defeated
Enter end and receive vision signal, output terminal output voltage input signal；The level translator input terminal receives the control source
Signal, output terminal output voltage output signal；The GOA circuit input ends receive the voltage output signal, output terminal connection
Each row grid line of liquid crystal panel；The method uses current foldback circuit of the present invention, the current foldback circuit difference
The sequential control circuit and the level translator are electrically connected, the described method comprises the following steps：Pass through the switch
Unit receive the voltage input signal of the voltage output end output of the sequential control circuit with connect the mirror current source and
The voltage output end of the level translator, makes the voltage output end of the level translator export and the voltage input signal
Corresponding voltage output signal is to the mirror current source；The voltage output signal is replicated by the mirror current source in real time
Charge to the charging capacitor；Pass through the voltage and overcurrent protection threshold value on the voltage comparator charging capacitor
Voltage, and output overcurrent protection signal closes the electricity when the voltage on the charging capacitor is more than overcurrent protection threshold voltage
Flat turn parallel operation.
It is an advantage of the current invention that exported by mirror current source to replicate the voltage output end of level translator in real time
Voltage output signal carry out stored charge amount to charging capacitor charging again, the instantaneous variation of voltage to the quantity of electric charge of charging capacitor not
Have big influence；And charging capacitor just can rapidly be charged to set overcurrent protection threshold value by only lasting high current
Voltage, so as to trigger overcurrent protection.Overcurrent protection from instantaneous peak current influence, it is therefore prevented that false triggering overcurrent protection can
Can property.And charging capacitor discharge reduction is controlled when the STV signals of sequential control circuit output are high level, no longer merely only
A current value is detected to protect overcurrent, realizes and overcurrent detecting protection is carried out in each STV signal periods.
Brief description of the drawings
Fig. 1, existing GOA circuit diagrams；
Fig. 2, the configuration diagram of current foldback circuit of the present invention；
Fig. 3, the circuit diagram shown in one embodiment of current foldback circuit of the present invention.
Embodiment
Below in conjunction with the accompanying drawings and embodiment, elaborate to current foldback circuit provided by the invention and method.It is aobvious
So, described embodiment is only part of the embodiment of the present invention, instead of all the embodiments.Based on the implementation in the present invention
Example, those of ordinary skill in the art's all other embodiments obtained without making creative work, belongs to
The scope of protection of the invention.
With reference to figure 2, the configuration diagram of current foldback circuit of the present invention.The current foldback circuit 22 is applied
In the drive circuit of liquid crystal panel, the drive circuit further includes sequential control circuit 20, level translator 29 and GOA circuits
(being not illustrated on figure)；The input terminal of the sequential control circuit 20 receives vision signal, output terminal output voltage input signal
CLK_IN；29 input terminal of level translator receives the voltage input signal CLK_IN, output terminal output voltage output letter
Number CLK_OUT；The GOA circuit input ends receive the voltage output signal CLK_OUT, and output terminal connects each of liquid crystal panel
Row grid line；The sequential control circuit 20 and the level translator 29 is electrically connected in the current foldback circuit 22.
The current foldback circuit 22 includes switch element 221, mirror current source 222, charging capacitor C1 and voltage comparator 223.
The switch element 221, it is defeated to be electrically connected the mirror current source 222, the voltage of sequential control circuit 20
The voltage output end CLK_OUT of outlet and level translator 29.The switch element 221 is used to receive the sequential control circuit
The voltage input signal of 20 voltage output end output is to connect the electricity of the mirror current source 222 and the level translator 29
Output terminal is pressed, the voltage output end of the level translator 29 is exported voltage output letter corresponding with the voltage input signal
Number CLK_OUT is to the mirror current source 222.For example, when the voltage output end of the sequential control circuit 20 is high level electricity
(the high level voltage output terminal is used for output high level voltage input signal CLK_IN, i.e. CLK_IN at this time during pressure output terminal
For high level VGH), then the switch element 221 is defeated in the high level voltage for receiving the high level voltage output terminal output
When entering signal CLK_IN conductings, the voltage output end of the mirror current source 222 and the level translator 29 is connected, is made described
The voltage output end output high level voltage of level translator 29 exports signal CLK_OUT to the mirror current source 222 (at this time
CLK_OUT is high level VGH)；When the voltage output end of the sequential control circuit 20 is low level voltage output terminal (at this time
It is low level VGL that the low level voltage output terminal, which is used to export low level voltage input signal CLK_IN, i.e. CLK_IN), then
The switch element 221 is receiving the low level voltage input signal CLK_IN conductings of the low level voltage output terminal output
When, the voltage output end of the mirror current source 222 and the level translator 29 is connected, makes the electricity of the level translator 29
Pressing output terminal output low level voltage output signal CLK_OUT, (CLK_OUT is low level at this time to the mirror current source 222
VGL)。
The mirror current source 222, is electrically connected the first end of the charging capacitor C1, and the second of the charging capacitor C1
End ground connection；The mirror current source 222 is used for duplication voltage output signal CLK_OUT in real time and charges to the charging capacitor C1.
Due to detecting the voltage output signal that the voltage output end of level translator 29 exports in real time by mirror current source 222
CLK_OUT carrys out stored charge amount to charging capacitor C1 chargings again, and the instantaneous variation of voltage will not to the quantity of electric charge of charging capacitor C1
There is big influence；And charging capacitor C1 just can rapidly be charged to set overcurrent protection threshold value by only lasting high current
Voltage, so as to trigger overcurrent protection.Overcurrent protection from instantaneous peak current influence, it is therefore prevented that false triggering overcurrent protection can
Can property.
The voltage comparator 223, first input end are electrically connected at the mirror current source 222 and the charging capacitor
The common port A0 of C1, the second input terminal are used to receive overcurrent protection threshold voltage VOCP, output terminal lotus root is connected to the level translator
29 input terminal；The voltage that the voltage comparator 223 is used on the charging capacitor C1 is more than the overcurrent protection threshold value
Voltage VOCPWhen output overcurrent protection signal close the level translator 29.
Preferably, the current foldback circuit further comprises control of discharge unit 224, the sequential control circuit 20
Voltage output end includes STV signal output parts, and the STV signal output parts are used to export STV signals (starting control signal)；Institute
Control of discharge unit 224 is stated, the charging capacitor C1 and STV signal output parts, the control of discharge unit is electrically connected
224 are used to control the charging capacitor C1 to discharge when the STV signals of STV signal output parts output are high level (HIGH)
Reset, so as to achieve the purpose that each STV signal period carries out overcurrent detecting protection, no longer merely only detect an electricity
Flow valuve protects overcurrent.
With reference to figure 3, the circuit diagram shown in one embodiment of current foldback circuit of the present invention.The electricity of level translator 29
The output pin of pressure output terminal is usually to be connected to PMOS and NMOS, and when NMOS is opened, PMOS is closed, otherwise also
So.The present embodiment is illustrated so that the voltage output end of the sequential control circuit 20 is high level voltage output terminal as an example, institute
Current foldback circuit connection mode and work when the voltage output end for stating sequential control circuit 20 is low level voltage output terminal
Principle is similar to the present embodiment, no longer separately illustrates.
In the present embodiment, the switch element 221 includes the first transistor Q1, the voltage of the sequential control circuit 20
For high level voltage output terminal, (the high level voltage output terminal is used for output high level voltage input signal to output terminal at this time
CLK_IN, i.e. CLK_IN are high level VGH)；The grid of the first transistor Q1 is electrically connected the mirror current source 222,
Source electrode is electrically connected the voltage output end of the level translator 29, and drain electrode is electrically connected the high level voltage output terminal.When
The first transistor Q1 is led when receiving the high level voltage input signal CLK_IN of the high level voltage output terminal output
It is logical, the voltage output end of the mirror current source 222 and the level translator 29 is connected, makes the electricity of the level translator 29
Pressing output terminal output high level voltage output signal CLK_OUT, (CLK_OUT is high level at this time to the mirror current source 222
VGH)；The mirror current source 222 replicates the high level voltage and exports signal CLK_OUT in real time to be filled to the charging capacitor C1
Electricity.Preferably, the first transistor Q1 is NMOS tube.
The control of discharge unit 224 includes third transistor Q3, and the voltage output end of the sequential control circuit includes
STV signal output parts (the STV signal output parts are used to export STV signals)；The grid of the third transistor Q3 is used to connect
The STV signals are received, the second end that source electrode is electrically connected the charging capacitor C1 is grounded at the same time, and drain electrode is electrically connected the charging
The first end of capacitance C1.When the STV signals are high level, the third transistor Q3 conductings, the charging capacitor C1 is put
Reset.Preferably, the third transistor Q3 is NMOS tube.
Voltage comparator 223 by the voltage on charging capacitor C1 with setting overcurrent protection threshold voltage VOCPCompare, when filling
Voltage on capacitance C1 is more than overcurrent protection threshold voltage VOCPWhen, overcurrent protection is triggered, level translator 29 is closed.
In other embodiments, the switch element 221 includes second transistor Q2, the electricity of the sequential control circuit 20
For low level voltage output terminal, (the low level voltage output terminal is used to export low level voltage input signal pressure output terminal at this time
CLK_IN, i.e. CLK_IN are low level VGL)；The grid of the second transistor Q2 is electrically connected the mirror current source 222,
Source electrode is electrically connected the voltage output end of the level translator 29, and drain electrode is electrically connected the low level voltage output terminal；When
The second transistor Q2 is led when receiving the low level voltage input signal CLK_IN of the low level voltage output terminal output
It is logical, the voltage output end of the mirror current source 222 and the level translator 29 is connected, makes the electricity of the level translator 29
Pressing output terminal output low level voltage output signal CLK_OUT, (CLK_OUT is low level at this time to the mirror current source 222
VGL)；The mirror current source 222 replicates the low level voltage and exports signal CLK_OUT in real time to be filled to the charging capacitor C1
Electricity.Preferably, the second transistor Q2 is PMOS tube.The switch element 221 can only include the first transistor Q1 or only
Including second transistor Q2, the first transistor Q1 and second transistor Q2 can also be included at the same time.When the switch element 221
When including the first transistor Q1 and second transistor Q2 at the same time, the first transistor Q1 and second transistor Q2 are each configured with
Corresponding mirror current source, charging capacitor and voltage comparator.
Present invention also offers a kind of over-current protection method, applied to the drive circuit of liquid crystal panel, the drive circuit
Further include sequential control circuit, level translator and GOA circuits；The input terminal of the sequential control circuit receives video letter
Number, output terminal output voltage input signal；The level translator input terminal receives the voltage input signal, output terminal output
Voltage output signal；The GOA circuit input ends receive the voltage output signal, and output terminal connects each row grid of liquid crystal panel
Line；The method uses current foldback circuit of the present invention, and the sequential is electrically connected in the current foldback circuit
Control circuit and the level translator, the described method comprises the following steps：When receiving described by the switch element 221
The voltage input signal CLK_IN of the voltage output end output of sequence control circuit 20 is to connect the mirror current source 222 and described
The voltage output end of level translator 29, makes the voltage output end of the level translator 29 export and the voltage input signal
The corresponding voltage output signal CLK_OUT of CLK_IN are to the mirror current source 222；It is real-time by the mirror current source 222
The voltage output signal CLK_OUT is replicated to charge to the charging capacitor C1；By described in the voltage comparator 223 comparison
Voltage and overcurrent protection threshold voltage V on charging capacitor C1OCP, and the voltage on the charging capacitor C1 is more than overcurrent
Rotection thresholds voltage VOCPWhen output overcurrent protection signal close the level translator 29.
It is defeated due to detecting the voltage that the voltage output end of level translator 29 exports in real time by mirror current source 222
Go out signal CLK_OUT and come stored charge amount, the electric charge of the instantaneous variation of voltage to charging capacitor C1 to charging capacitor C1 chargings again
Amount does not have big influence；And charging capacitor C1 just rapidly can be charged to set overcurrent and protected by only lasting high current
Threshold voltage is protected, so as to trigger overcurrent protection.Overcurrent protection from instantaneous peak current influence, it is therefore prevented that false triggering overcurrent protect
The possibility of shield.
Wherein, (the height at this time when the voltage output end of the sequential control circuit 20 is high level voltage output terminal
Level voltage output terminal is high level VGH for output high level voltage input signal CLK_IN, i.e. CLK_IN), then it is described to open
Close unit 221 to turn on when receiving the high level voltage input signal CLK_IN of the high level voltage output terminal output, even
Lead to the voltage output end of the mirror current source 222 and the level translator 29, make the voltage of the level translator 29 defeated
Outlet output high level voltage exports signal CLK_OUT to the mirror current source 222 (CLK_OUT is high level VGH at this time)；
(the low level voltage output terminal at this time when the voltage output end of the sequential control circuit 20 is low level voltage output terminal
It is low level VGL for exporting low level voltage input signal CLK_IN, i.e. CLK_IN), then the switch element 221 is receiving
To the low level voltage output terminal output low level voltage input signal CLK_IN when turn on, connect the mirror current source
222 and the voltage output end of the level translator 29, the voltage output end of the level translator 29 is exported low level electricity
Pressure exports signal CLK_OUT to the mirror current source 222 (CLK_OUT is low level VGL at this time).
Preferably, when the current foldback circuit further includes control of discharge unit 224, the electricity of the sequential control circuit 20
Pressure output terminal includes STV signal output parts (the STV signal output parts are used to export STV signals), the control of discharge unit
When the charging capacitor and the STV signal output parts is electrically connected, the method is further included：Pass through the electric discharge
Control unit 224 receives the STV signals of the STV signal output parts output, when the STV signals are high level described in control
Charging capacitor C1 discharge reductions.So as to achieve the purpose that each STV signal period carries out overcurrent detecting protection, no longer merely
A current value is only detected to protect overcurrent in ground.
Current foldback circuit provided by the invention and method, level translator is replicated by mirror current source in real time
The voltage output signal of voltage output end output carrys out stored charge amount to charging capacitor charging again, and the instantaneous variation of voltage is to charging
The quantity of electric charge of capacitance does not have big influence；And only lasting high current just rapidly charging capacitor can be charged to it is set
Overcurrent protection threshold voltage, so as to trigger overcurrent protection.Overcurrent protection from instantaneous peak current influence, it is therefore prevented that false touch
Send out the possibility of overcurrent protection.And control charging capacitor electric discharge multiple when the STV signals of sequential control circuit output are high level
Position, no longer merely only detects a current value to protect overcurrent, realizes and carry out overcurrent detecting in each STV signal periods
Protection.
The above is only the preferred embodiment of the present invention, it is noted that for the ordinary skill people of the art
Member, various improvements and modifications may be made without departing from the principle of the present invention, these improvements and modifications also should be regarded as
Protection scope of the present invention.
Claims (10)
1. a kind of current foldback circuit, applied to the drive circuit of liquid crystal panel, the drive circuit further includes timing control electricity
Road, level translator and GOA circuits；The input terminal of the sequential control circuit receives vision signal, output terminal output voltage
Input signal；The level translator input terminal receives the voltage input signal, output terminal output voltage output signal；It is described
GOA circuit input ends receive the voltage output signal, and output terminal connects each row grid line of liquid crystal panel；It is characterized in that, institute
State current foldback circuit and the sequential control circuit and the level translator is electrically connected；The current foldback circuit
Including switch element, mirror current source, charging capacitor and voltage comparator；
The switch element, is electrically connected the mirror current source, the voltage output end of the sequential control circuit and institute
The voltage output end of level translator is stated, the switch element is used for the voltage output end output for receiving the sequential control circuit
Voltage input signal to connect the voltage output end of the mirror current source and the level translator, make the level conversion
The voltage output end of device exports voltage output signal corresponding with the voltage input signal to the mirror current source；
The mirror current source, is electrically connected the first end of the charging capacitor, and the second end ground connection of the charging capacitor is described
Mirror current source charges for replicating the voltage output signal in real time to the charging capacitor；
The voltage comparator, first input end be electrically connected at the mirror current source and the charging capacitor first end it
Between common port, the second input terminal be used for receive overcurrent protection threshold voltage, output terminal lotus root is connected to the defeated of the level translator
Enter end, the voltage comparator is used to export when the voltage on the charging capacitor is more than the overcurrent protection threshold voltage
Protection signal is flowed, to close the level translator.
2. current foldback circuit as claimed in claim 1, it is characterised in that the switch element includes the first transistor, institute
Stating the voltage output end of sequential control circuit includes high level voltage output terminal, and the grid of the first transistor is electrically connected institute
Mirror current source is stated, source electrode is electrically connected the voltage output end of the level translator, and drain electrode is electrically connected the high level electricity
Press output terminal；When the first transistor receives the high level voltage input signal of the high level voltage output terminal output
Conducting, connects the voltage output end of the mirror current source and the level translator, makes the voltage of the level translator defeated
Outlet output high level voltage outputs signal to the mirror current source；The mirror current source replicates the high level electricity in real time
Pressure outputs signal to the charging capacitor charging.
3. current foldback circuit as claimed in claim 2, it is characterised in that the first transistor is NMOS tube.
4. current foldback circuit as claimed in claim 1, it is characterised in that the switch element includes second transistor, institute
Stating the voltage output end of sequential control circuit includes low level voltage output terminal, and the grid of the second transistor is electrically connected institute
Mirror current source is stated, source electrode is electrically connected the voltage output end of the level translator, and drain electrode is electrically connected the low level electricity
Press output terminal；When the second transistor receives the low level voltage input signal of the low level voltage output terminal output
Conducting, connects the voltage output end of the mirror current source and the level translator, makes the voltage of the level translator defeated
Outlet output low level voltage outputs signal to the mirror current source；The mirror current source replicates the low level electricity in real time
Pressure outputs signal to the charging capacitor charging.
5. current foldback circuit as claimed in claim 4, it is characterised in that the second transistor is PMOS tube.
6. current foldback circuit as claimed in claim 1, it is characterised in that the current foldback circuit further includes control of discharge
Unit, the voltage output end of the sequential control circuit include STV signal output parts；
The control of discharge unit, is electrically connected the charging capacitor and the STV signal output parts, the control of discharge
Unit is used to control the charging capacitor discharge reduction when the STV signals of STV signal output parts output are high level.
7. current foldback circuit as claimed in claim 6, it is characterised in that the control of discharge unit includes the 3rd crystal
Pipe, the grid of the third transistor are used to receive the STV signals, and the second end that source electrode is electrically connected the charging capacitor is same
When be grounded, drain electrode is electrically connected the first end of the charging capacitor；
When the STV signals are high level, the third transistor conducting, the charging capacitor discharge reduction.
8. current foldback circuit as claimed in claim 7, it is characterised in that the third transistor is NMOS tube.
9. a kind of over-current protection method, applied to the drive circuit of liquid crystal panel, the drive circuit further includes timing control electricity
Road, level translator and GOA circuits；The input terminal of the sequential control circuit receives vision signal, output terminal output voltage
Input signal；The level translator input terminal receives the voltage input signal, output terminal output voltage output signal；It is described
GOA circuit input ends receive the voltage output signal, and output terminal connects each row grid line of liquid crystal panel；It is characterized in that, institute
Method is stated to be electrically connected using the current foldback circuit described in claim 1-5 any one, the current foldback circuit
The sequential control circuit and the level translator, the described method comprises the following steps：
Voltage input signal that the voltage output end of the sequential control circuit exports is received by the switch element to connect
The voltage output end of the mirror current source and the level translator, make the level translator voltage output end export with
The corresponding voltage output signal of voltage input signal is to the mirror current source；
The voltage output signal is replicated in real time by the mirror current source to charge to the charging capacitor；
By the voltage and overcurrent protection threshold voltage on the voltage comparator charging capacitor, and filled described
Output overcurrent protection signal closes the level translator when voltage on capacitance is more than overcurrent protection threshold voltage.
10. over-current protection method as claimed in claim 9, it is characterised in that the current foldback circuit further includes electric discharge control
Unit processed, the voltage output end of the sequential control circuit include STV signal output parts, and the control of discharge unit difference is electrical
Connect the charging capacitor and the STV signal output parts；The method is further included：
The STV signals of the STV signal output parts output are received by the control of discharge unit, are height in the STV signals
The charging capacitor discharge reduction is controlled during level.
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| CN201711127971.2A CN107909972A (en) | 2017-11-15 | 2017-11-15 | Current foldback circuit and method |
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| CN201711127971.2A CN107909972A (en) | 2017-11-15 | 2017-11-15 | Current foldback circuit and method |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109346019A (en) * | 2018-11-22 | 2019-02-15 | 深圳市华星光电技术有限公司 | Overcurrent protection control circuit for level shift circuit |
| CN109410884A (en) * | 2018-12-27 | 2019-03-01 | 惠科股份有限公司 | Overcurrent protection module and display device |
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Application publication date: 20180413 |