CN108599096B - Current foldback circuit and method, display device - Google Patents
Current foldback circuit and method, display device Download PDFInfo
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- CN108599096B CN108599096B CN201810717527.4A CN201810717527A CN108599096B CN 108599096 B CN108599096 B CN 108599096B CN 201810717527 A CN201810717527 A CN 201810717527A CN 108599096 B CN108599096 B CN 108599096B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0007—Details of emergency protective circuit arrangements concerning the detecting means
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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
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Abstract
This disclosure relates to field of display technology more particularly to a kind of current foldback circuit and method, display device.The circuit may include operational amplifier, the first transistor, current sensor, the first current comparator, the first current source, the second current comparator, the second current source, second transistor, first resistor, second resistance, 3rd resistor.The disclosure can guarantee that the via hole of liquid crystal display panel is not burned out and short dot temperature is no more than a certain range; the stability of liquid crystal display panel is improved, while can avoid the problem of can not implementing protection since the detecting time is longer occur, in other words; it can avoid accidentally detecting, can also implement to protect.
Description
Technical field
This disclosure relates to field of display technology more particularly to a kind of current foldback circuit and method, display device.
Background technique
Array substrate row drives (Gate Driver on Array, abbreviation GOA) technology, is to utilize existing TFT-LCD gusts
Grid (Gate) horizontal drive circuit is produced in array substrate by column (Array) processing procedure, realizes the driving progressively scanned to grid
One technology of mode.Since GOA circuit can be directly made in around liquid crystal display panel, making technology is simplified, but also can drop
Low product cost improves the integrated level of liquid crystal display panel, and panel is made to tend to be thinned.
It is desirable to which clock signal, gate drive signal etc. can drive GOA circuit.Above-mentioned clock signal, gate driving
Signal etc. is generated by sequential control circuit (TCON).Due to some processing procedures etc., may cause input GOA circuit when
Short circuit occurs for clock signal, gate drive signal etc., in turn results in the great increase of electric current.Excessive electric current will lead to liquid crystal display panel
Temperature increases, and burns out or even cause fire.In view of the above problems, usually pass through OCP (Over Current Protection, mistake
Stream protection circuit) clock signal, gate drive signal etc. inputted into GOA circuit, rather than by clock signal, gate drive signal
Etc. directly inputting GOA circuit, so that OCP opens protection when clock signal, gate drive signal etc. increase sharply, guarantee liquid crystal display panel
Via hole be not burned out and Short point temperature be no more than a certain range.
Currently, the detecting time of common OCP is longer, i.e. the time of starting protection is longer in order to avoid accidentally detecting.So
And the OCP of longer detecting time can not play real protective effect, it is therefore desirable to which providing a kind of can avoid accidentally detecting while can
Realize the OCP of protection.
It should be noted that information is only used for reinforcing the reason to the background of the disclosure disclosed in above-mentioned background technology part
Solution, therefore may include the information not constituted to the prior art known to persons of ordinary skill in the art.
Summary of the invention
The disclosure is designed to provide a kind of current foldback circuit and method, display device, and then at least in certain journey
The problems such as overcoming current foldback circuit that can not play a protective role on degree.
According to one aspect of the disclosure, a kind of current foldback circuit is provided, comprising:
Operational amplifier, first end connects first node, second end connects second node, and third end connects fourth node；
The first transistor connects the fourth node, is connected for responding the signal of the fourth node, and first
Electric current is exported to the third node under the action of power supply signal；
Current sensor, the output end of connection third node, the current foldback circuit, for third described in real-time detection
The electric current of node；
First current comparator connects the current sensor, for obtaining described the of current sensor detection in real time
The electric current of three nodes, and when the difference of the electric current of the third node at current time and last moment is more than a preset difference value
The first comparison result is generated, and generates feedback current；
First current source connects first current comparator and second node, for obtaining first comparison result,
And the first electric current is inputted to the second node according to first comparison result；
Second current comparator connects first current comparator and current sensor, passes for obtaining the electric current
The electric current and the feedback current of the third node of sensor detection, and according to the electric current of the third node, the feedback
Electric current, threshold current and a detecting time generate the second comparison result；
Second current source connects second current comparator and the 5th node, for obtaining second comparison result,
And the second electric current is inputted to the 5th node according to second comparison result；
Second transistor connects the 5th node, is connected for responding the signal of the 5th node, makes described the
The electric current of three nodes is transmitted to internal ground wire along the second transistor；
First resistor is connected between the input terminal of the current foldback circuit and the first node；
Second resistance is connected between the first node and the third node；
3rd resistor, first end connect the second node, and second end receives second source signal.
In a kind of exemplary embodiment of the disclosure,
The first transistor, the control terminal connection fourth node, first end reception first power supply signal, second
End connects the third node；
The current sensor, first end connect the third node, and second end connects the defeated of the current foldback circuit
Outlet；
First current comparator, first end connect the third end of the current sensor；
First current source, first end connect the second end of first current comparator, second end connection described the
Two nodes；
Second current comparator, first end connect first current comparator third end and the current sense
The third end of device；
Second current source, first end connect the second end of second current comparator, second end connection described the
Five nodes；
The second transistor, control terminal connect the 5th node, and first end connects the internal ground wire, and second end connects
Connect the third node.
In a kind of exemplary embodiment of the disclosure, the circuit further includes communication interface, in which:
The communication interface connects the third end of second current comparator, for will the threshold current write-in described in
Second current comparator.
In a kind of exemplary embodiment of the disclosure, the circuit further includes the 4th resistance and the 5th resistance, in which:
4th resistance is connected between the second node and the second end of first current source；
5th resistance is connected between the third node and the internal ground wire.
In a kind of exemplary embodiment of the disclosure, the circuit further includes the 6th resistance and the 7th resistance, in which:
6th resistance is connected between the 5th node and the control terminal of the second transistor；
7th resistance, is connected between the third end of the operational amplifier and the fourth node.
In a kind of exemplary embodiment of the disclosure, the generation feedback current includes:
The feedback current is calculated according to following formula:
Wherein, IfFor the feedback current, IjFor the electric current of the input terminal under non-initial state, I0For original state
Under the input terminal electric current, V0For the voltage of the input terminal, IaFor the electricity in the 3rd resistor under non-initial state
Stream, IbFor the electric current in the 3rd resistor under original state, R3For the resistance value of the 3rd resistor, R1For first electricity
The resistance value of resistance.
In a kind of exemplary embodiment of the disclosure, it is described according to the electric current of the third node, the feedback current,
Threshold current and a detecting time generate the second comparison result and include:
By the sum of the electric current of the third node and described feedback current compared with the threshold current, and in the third
When the duration that the sum of the electric current of node and the feedback current are greater than the threshold current is more than the detecting time, generate
Second comparison result.
According to one aspect of the disclosure, a kind of over-current protection method is provided, for driving described in above-mentioned any one
Current foldback circuit, comprising:
Input signal is inputted to the input terminal of current foldback circuit, so that the input signal passes through first resistor and second
Resistive transmission is to third node；
Pass through the electric current of third node described in current sensor real-time detection；
It obtains the electric current of the third node of the current sensor detection in real time using the first current comparator, and counts
The difference of the electric current of the third node of current time and last moment is calculated, and when the difference is more than a preset difference value,
The first comparison result is generated, and generates feedback current；
First comparison result is obtained by the first current source, and according to first comparison result to the second node
The first electric current is inputted, to change the voltage of the third node according to first electric current, operational amplifier, the first transistor；
Control the electric current that second current comparator obtains the third node of the current sensor detection in real time
And the feedback current, and it is greater than holding for the threshold current in the sum of the electric current of the third node and the feedback current
When the continuous time is more than the detecting time, the second comparison result is generated；
The second electric current is inputted to the 5th node according to second comparison result by the second current source；
By the second current lead-through second transistor, the electric current of the third node is passed along the second transistor
Transport to internal ground wire.
In a kind of exemplary embodiment of the disclosure, the current foldback circuit further includes communication interface；The method
Further include:
Second current comparator is written into the threshold current using the communication interface.
According to one aspect of the disclosure, a kind of display device is provided, including overcurrent described in above-mentioned any one
Protect circuit.
The current foldback circuit and method, display device that a kind of exemplary embodiment of the disclosure provides, overcurrent protection electricity
Road may include: operational amplifier, the first transistor, current sensor, the first current comparator, the first current source, the second electricity
Flow comparator, the second current source, second transistor, first resistor, second resistance, 3rd resistor.In the current foldback circuit work
During work, on the one hand, calculate the electric current of the third node of current time and last moment by the first current comparator
Difference, and when difference is greater than preset difference value, that is, when detecting that the electric current of third node increases sharply, generate the first comparison result, control
Make the first current source according to the first comparison result to second node export the first electric current, with by the first electric current, operational amplifier,
The first transistor changes the voltage of third node, to ensure that the electric current of third node is maintained at maintenance level, guarantees liquid crystal display panel
Via hole be not burned out and short dot temperature be no more than a certain range, improve the stability of liquid crystal display panel；On the other hand,
When the duration that the sum of the electric current of three nodes and the feedback current are greater than the threshold current is more than the detecting time, by the
The electric current of third node is transmitted to internal ground wire along the second transistor by two current lead-through second transistors, that is, is opened and protected
Shield guarantees that the via hole of liquid crystal display panel is not burned out and short dot temperature is no more than a certain range, improves the stabilization of liquid crystal display panel
Property；Another aspect carries out above two protected mode (i.e. the mode of the mode of adjustment third node voltage and unlatching protection)
In conjunction with, though detecting the time it is longer, can also be protected by adjusting the mode of the voltage of third node, avoid the occurrence of due to
The detecting time is longer and can not implement the problem of protecting, in other words, can avoid accidentally detecting, and can also implement to protect.
It should be noted that information is only used for reinforcing the reason to the background of the disclosure disclosed in above-mentioned background technology part
Solution, therefore may include the information not constituted to the prior art known to persons of ordinary skill in the art.
Detailed description of the invention
It is described in detail its exemplary embodiment by referring to accompanying drawing, the above and other feature and advantage of the disclosure will become
It obtains more obvious.It should be evident that the accompanying drawings in the following description is only some embodiments of the present disclosure, it is common for this field
For technical staff, without creative efforts, it is also possible to obtain other drawings based on these drawings.Attached
In figure:
Fig. 1 is a kind of schematic diagram one of current foldback circuit of the disclosure；
Fig. 2 is a kind of schematic diagram two of current foldback circuit of the disclosure；
Fig. 3 is a kind of schematic diagram three of current foldback circuit of the disclosure；
Fig. 4 is a kind of schematic diagram four of current foldback circuit of the disclosure；
Fig. 5 is a kind of flow chart of over-current protection method of the disclosure.
Specific embodiment
Example embodiment is described more fully with reference to the drawings.However, example embodiment can be real in a variety of forms
It applies, and is not understood as limited to embodiment set forth herein；On the contrary, thesing embodiments are provided so that the disclosure will be comprehensively and complete
It is whole, and the design of example embodiment is comprehensively communicated to those skilled in the art.Described feature, structure or characteristic can
Be incorporated in one or more embodiments in any suitable manner.In the following description, provide many details from
And it provides and embodiment of the disclosure is fully understood.It will be appreciated, however, by one skilled in the art that can be of the disclosure
Technical solution, or can be using other methods, constituent element, material, dress without one or more in the specific detail
It sets, step etc..In other cases, known solution is not shown in detail or describes to avoid fuzzy all aspects of this disclosure.
In addition, attached drawing is only the schematic illustrations of the disclosure, not necessarily it is drawn to scale.Identical attached drawing in figure
Label identifies the same or similar part, thus will omit repetition thereof.
In the related art, common OCP is Lever Shifter (level translator).Most of Lever Shifter
When starting protection need simultaneously meet two conditions, it may be assumed that controller electric current, overcurrent time be more than detect the time.For
It avoids accidentally detecting, the detecting overlong time of most of Lever Shifter, therefore can not play a protective role.Such as certain Lever
It is more than 100mA that Shifter, which opens the condition of protection as electric current, and the detecting time is 100us, is based on this, for full HD product, often
Capable sweep time is 14.8us, and for ultra high-definition product, the sweep time of every row then can be shorter, therefore, in Lever
When the protection of Shifter is also inactive, via hole has just been burnt and electric current is restored to normal value, and Lever Shifter can not yet
Restart, and then can not play a protective role.Further, since the resistance inside the liquid crystal display panel of different machines is inconsistent, clock
The electric current of signal, gate drive signal etc. is also inconsistent, however a threshold current is only arranged inside Lever Shifter, very
Difficulty meets the requirement of heterogenous.
To solve the above-mentioned problems, a kind of current foldback circuit is provided in this example embodiment, it is shown referring to Fig.1,
The current foldback circuit may include: operational amplifier A, the first transistor T1, current sensor 101, the first current comparator
102, the first current source 103, the second current comparator 104, the second current source 105, second transistor T2, first resistor R1,
Two resistance R2,3rd resistor R3.Wherein:
Operational amplifier A, first end connects first node N1, second end connects second node N2, third end connection the 4th
Node N4；
The first transistor T1 connects the fourth node N4, is connected for responding the signal of the fourth node N4, and
Electric current is exported to the third node N3 under the action of the first power supply signal VDD；
Current sensor 101, the output end OUTPUT of connection third node N3, the current foldback circuit, for real-time
Detect the electric current of the third node N3；
First current comparator 102 connects the current sensor 101, detects for obtaining current sensor 101 in real time
The third node N3 electric current, and calculate the difference of the electric current of the third node N3 of current time and last moment,
And when the difference of the electric current of the third node N3 at current time and last moment is more than a preset difference value, the first ratio is generated
Compared with as a result, and generation feedback current；
First current source 103 connects first current comparator 102 and second node N2, for obtaining described first
Comparison result, and the first electric current is inputted to the second node N2 according to first comparison result；
Second current comparator 104 connects first current comparator 102, the current sensor 101, for obtaining
The electric current and the feedback current for the third node N3 for taking the current sensor 101 to detect, and according to the third section
Electric current, the feedback current, threshold current and the detecting time of point N3 generates the second comparison result；
Second current source 106 connects second current comparator 104 and the 5th node N5, for obtaining described second
Comparison result, and the second electric current is inputted to the 5th node N5 according to second comparison result；
Second transistor T2 connects the 5th node N5, is connected, makes for responding the signal of the 5th node N5
The electric current of the third node N3 is transmitted to internal ground wire VL along the second transistor T2；
First resistor R1, first end connect the input terminal INPUT of the current foldback circuit, second end connection described first
Node N1；
Second resistance R2, first end connect the first node N1, and second end connects the third node N3；
3rd resistor R3, first end connect the second node N2, and second end receives second source signal VSS.
In the present example embodiment, the preset difference value can voluntarily be determined by testing crew, for example, can be
10uA, or 20uA etc., the present exemplary embodiment is not particularly limited this.May include in first comparison result
The difference of the electric current of the third node at current time and last moment.
The generation feedback current may include: to calculate the feedback current according to following formula:
Wherein, IfFor the feedback current, IjFor the electric current of the input terminal INPUT under non-initial state, I0It is initial
The electric current of the input terminal INPUT under state, V0For the voltage of the input terminal INPUT, IaDescribed under non-initial state
Electric current (i.e. electric current of the first current source 103 under non-initial state) on 3rd resistor R3, IbDescribed under original state
Electric current (i.e. the electric current of the first current source 103 in the initial state) on 3rd resistor R3, R3For the resistance of the 3rd resistor R3
Value, R1For the resistance value of the first resistor R1.
It should be noted that original state herein can be understood as the state when the electric current of third node N3 is stablized,
Non-initial state can be understood as the state when the electric current of third node N3 increases sharply.
It is described to generate the according to the electric current of the third node N3, the feedback current, threshold current and a detecting time
Two comparison results may include: by the sum of the electric current of the third node N3 and described feedback current and the threshold current ratio
Compared with, and be more than institute in the duration that the sum of the electric current of the third node N3 and the feedback current are greater than the threshold current
When stating the detecting time, the second comparison result is generated.In the present example embodiment, the detecting time can be set by developer
It sets, can be 100us, can also be 50us, the present exemplary embodiment is not particularly limited this.The threshold current can be with
According to demand be configured, the present exemplary embodiment is not particularly limited this.The input signal of the input terminal INPUT can
Think clock signal or gate drive signal etc., the present exemplary embodiment is not particularly limited this.
The specific connection type of the current foldback circuit in Fig. 1 is illustrated below.
The control terminal of the first transistor T1 connects the fourth node N4, the first termination of the first transistor T1
The first power supply signal VDD is received, the second end of the first transistor T1 connects the third node N3；The current sense
The first end of device 101 connects the third node N3, and the second end of the current sensor 101 connects the current foldback circuit
Output end OUTPUT；The first end of first current comparator 102 connects the third end of the current sensor 101；Institute
The first end for stating the first current source 103 connects the second end of first current comparator 102, first current source 103
Second end connects the second node N2；The first end of second current comparator 104 connects first current comparator
102 third end and the third end of the current sensor 101；The first end connection described second of second current source 105
The second end of the second end of current comparator 104, second current source 105 connects the 5th node N5；Described second is brilliant
The control terminal of body pipe T2 connects the 5th node N5, and the first end of the second transistor T2 connects the internal ground wire VL,
The second end of the second transistor T2 connects the third node N3.
In the present example embodiment, the first transistor T1 and second transistor T2 all have control terminal, first end
And second end, the control terminal of each transistor can be base stage, the first end of each transistor can be emitter, each transistor
Two ends can be collector；Alternatively, it can be current collection that the control terminal of each transistor, which can be base stage, the first end of each transistor,
Pole, each transistor second end can be emitter.Each transistor can be N-type transistor or P-type transistor, this example
Property embodiment is not particularly limited this.Each transistor can be depletion mode transistor and enhancement transistor, this is exemplary
Embodiment is not particularly limited this.The specific current potential of first power supply signal and second source signal can be according in circuit
The type of each element be determined, the present exemplary embodiment is to this insufficient particular determination.
The operational amplifier has first end, second end, third end.Specifically, first end can for noninverting input,
Second end can be reverse input end, and third end can be output end；Or first end can be reverse input end, second end can
Think noninverting input, third end can be output end, and the present exemplary embodiment is not particularly limited this, such as can be by developing
Personnel are determined as the case may be.The current sensor for example can be current divider, electromagnetic current transducer, electronics
Formula current transformer etc., this implementation embodiment are not particularly limited this.
On this basis, as shown in Fig. 2, the circuit can also include communication interface 106, in which: the communication interface
The third end of 106 connection second current comparators 104, for second current comparator to be written in the threshold current
106.In the present example embodiment, described to be connect by interface 106 for I2C (Inter-Integrated Circuit)
Mouthful.The writing mode of the threshold voltage may include the modes such as external burning, and the present exemplary embodiment does not make special limit to this
It is fixed.The second current comparator 104 is written into threshold current using communication interface 106, allows user according to current tool situation
Threshold current is written, even if threshold current is adjustable, and then meets the needs of heterogenous.
On this basis, as described in Figure 3, the circuit can also include the 4th resistance R4 and the 5th resistance R5, in which:
The 4th resistance R4 is connected between the second node N2 and the second end of first current source 103, i.e.,
The first end of the 4th resistance R4 connects the second node N2, the second end connection of the 4th resistance R4 first electricity
The second end in stream source 103；The 5th resistance R5 is connected between the third node N3 and the internal ground wire VL, i.e., described
The first end of 5th resistance R5 connects the third node N3, and the second end of the 5th resistance R5 connects the internal ground wire
VL。
On this basis, as shown in figure 4, the circuit can also include the 6th resistance R6 and the 7th resistance R7, in which:
The 6th resistance R6 is connected between the 5th node N5 and the control terminal of the second transistor T2, i.e. institute
The first end for stating the 6th resistance R6 connects the 5th node N5, and the second end of the 6th resistance R6 connects second crystal
The control terminal of pipe T2；The 7th resistance R7 is connected between the third end of the operational amplifier A and the fourth node N4,
The first end of the i.e. described 7th resistance R7 connects the third end of the operational amplifier A, and the second end of the 7th resistance R7 connects
Meet the fourth node N4.
In conclusion during the work of above-mentioned current foldback circuit, on the one hand, pass through the first current comparator 102
The difference of the electric current of the third node N3 of current time and last moment is calculated, and when difference is greater than preset difference value, that is, is detected
To third node N3 electric current increase sharply when, generate the first comparison result, control the first current source 103 according to the first comparison result to
Second node N2 exports the first electric current, to change third node N3 by the first electric current, operational amplifier A, the first transistor T1
Voltage, to ensure that the electric current of third node N3 is maintained at maintenance level, guarantee the via hole of liquid crystal display panel be not burned out and short circuit
Point temperature is no more than a certain range, improves the stability of liquid crystal display panel；On the other hand, the electric current of third node N3 with it is described
When the duration that the sum of feedback current is greater than the threshold current is more than the detecting time, pass through second the second crystal of current lead-through
The electric current of third node N3 is transmitted to internal ground wire VL along the second transistor T2 by pipe T2, that is, opens protection, guarantees liquid crystal
The via hole of panel is not burned out and short dot temperature is no more than a certain range, improves the stability of liquid crystal display panel；Another aspect,
Above two protected mode (i.e. the mode of the mode of adjustment third node voltage and unlatching protection) is combined, even if detecting
Time is longer, can also be protected by adjusting the mode of the voltage of third node N3, avoid the occurrence of due to detecting the time compared with
It is long and the problem of protection can not be implemented, in other words, can avoid accidentally detecting, can also implement to protect.
In an exemplary embodiment of the disclosure, a kind of over-current protection method is additionally provided, it is as described in Figure 1 for driving
Current foldback circuit, as shown in figure 5, the over-current protection method may comprise steps of:
Step S510, input signal is inputted to the input terminal INPUT of current foldback circuit, so that the input signal passes through
First resistor R1 and second resistance R2 is transmitted to third node N3.In the present example embodiment, the input signal can be
Clock signal, gate drive signal etc., the present exemplary embodiment is not particularly limited this.
Step S520, pass through the electric current of third node N3 described in 101 real-time detection of current sensor.
Step S530, the third that the current sensor 101 detects is obtained in real time using the first current comparator 102
The electric current of node N3, and the difference of the electric current of the third node N3 of current time and last moment is calculated, and in the difference
When value is more than a preset difference value, the first comparison result is generated, and generate feedback current.
In the present example embodiment, first comparison result includes the third section of current time and last moment
The difference of the electric current of point N3.The calculation of the feedback current are as follows:
Wherein, IfFor the feedback current, IjFor the electric current of the input terminal INPUT under non-initial state, I0It is initial
The electric current of the input terminal INPUT under state, V0For the voltage of the input terminal INPUT, IaDescribed under non-initial state
Electric current (i.e. electric current of the first current source 103 under non-initial state) on 3rd resistor R3, IbDescribed under original state
Electric current (i.e. the electric current of the first current source 103 in the initial state) on 3rd resistor R3, R3For the resistance of the 3rd resistor R3
Value, R1For the resistance value of the first resistor R1.
It should be noted that original state herein can be understood as the state when the electric current of third node N3 is stablized,
Non-initial state can be understood as the state when the electric current of third node N3 increases sharply.
Step S540, first comparison result is obtained by the first current source 103, and according to first comparison result to
The second node N2 inputs the first electric current, to change institute according to first electric current, operational amplifier A, the first transistor T1
State the voltage of third node N3.
In the present example embodiment, the first current source 103 (i.e. current time and last moment according to the first comparison result
The third node N3 electric current difference) calculate the first electric current numerical value, and to second node N2 input the first electric current, with
Change the voltage of second node N2 according to the first electric current, and then changes the electricity of third node N3 according to the voltage of second node N2
Pressure, to guarantee that the electric current of third node N3 maintains in stable level.The mistake of the specific voltage for changing third node N3
Journey includes: according to operational amplifier A property: the voltage V of second node N2N2With the voltage V of first node N1N1It is equal, i.e.,
VN2=VN1, the voltage V of third node N3N3With the voltage V of first node N1N1Relationship be VN3-VN1=(VN1-V0)*R2/R1, again
Due to VN2=I1*R3, above-mentioned formula is calculated it is found that VN3=(I1*R3-V0)*R2/R1+I1*R3, wherein V0It is described defeated
Enter to hold the voltage of INPUT, R1、R2、R3The respectively resistance value of first resistor R1, second resistance R2,3rd resistor R3, I1It is first
Electric current.From above-mentioned formula it is found that the voltage V of third node N3N3With the first electric current I1For positive correlation, therefore, in third section
It, can be according to the first electric current I when the electric current of point N3 increases sharply1Reduce the voltage V of third node N3N3, so that it is guaranteed that third section
The electric current of point N3 maintains in stable level.
From the foregoing, it will be observed that calculating the electricity of the third node N3 of current time and last moment by the first current comparator 102
The difference of stream, and when difference is greater than preset difference value, that is, when detecting that the electric current of third node N3 increases sharply, generates first and compare knot
Fruit, control the first current source 103 according to the first comparison result to second node N2 export the first electric current, with by the first electric current,
Operational amplifier A, the first transistor T1 change the voltage of third node N3, to ensure that the electric current of third node N3 is maintained at stable
Level guarantees that the via hole of liquid crystal display panel is not burned out and short dot temperature is no more than a certain range, improves the steady of liquid crystal display panel
It is qualitative.
It should be noted that the first transistor T1 can promote the driving capability of load.
Step S550, it controls second current comparator 104 and obtains the described of the detection of current sensor 101 in real time
The electric current and the feedback current of third node N3, and it is big in the sum of the electric current N3 of the third node and the feedback current
When the duration of the threshold current being more than the detecting time, the second comparison result is generated.
In the present example embodiment, the third node N3 that the second current comparator 104 measures current sensor inspection 101
Electric current and feedback current summation after, the third node that is compared with threshold current, and is detected in current sensor 101
When the duration that the sum of electric current and feedback current of N3 are greater than threshold current is more than the detecting time, the second comparison result is generated,
Second comparison result may include the request for opening protection.The detecting time can be configured by developer, for example, can be with
It can also be 200us etc., the present exemplary embodiment is not particularly limited this for 100us.
Step S560, by the second current source 105 according to second comparison result to the 5th node N5 input the
Two electric currents.
In the present example embodiment, the request protected in the second current source 105 according to the unlatching in the second comparison result,
The second electric current is calculated, and inputs the second electric current to the 5th node N5.It should be noted that the size of the second electric current has to be larger than
The firing current of two-transistor T2.In normal state, i.e. when the electric current of third node N3 is normal, the size of the second electric current is 0.
Step S570, by the second current lead-through second transistor T2, by the electric current of the third node N3 along institute
It states second transistor T2 and is transmitted to internal ground wire VL.
In the present example embodiment, second transistor T2 is connected by the effect of the second electric current of the 5th node N5, made
The electric current of third node N3 is transmitted to internal ground wire VL along second transistor T2, to open protection, stops to overcurrent protection electric current
Output end OUTPUT export electric current, guarantee the via hole of liquid crystal display panel be not burned out and Short point temperature be no more than a certain range,
Improve the stability of liquid crystal display panel.
In conclusion the sum of the electric current of third node N3 and the feedback current be greater than the threshold current it is lasting when
Between when being more than the detecting time, it is by the second current lead-through second transistor T2, the electric current of third node N3 is brilliant along described second
Body pipe T2 is transmitted to internal ground wire VL, that is, opens protection, guarantee that the via hole of liquid crystal display panel is not burned out and short dot temperature does not surpass
A certain range is crossed, the stability of liquid crystal display panel is improved；In addition, by above two protected mode (i.e. adjustment third node voltage
Mode and open protection mode) be combined, even if detecting the time it is longer, can also be by adjusting the electricity of third node N3
The mode of pressure is protected, and avoids the occurrence of the problem of can not implementing protection since the detecting time is longer, in other words, can avoid
It accidentally detects, can also implement to protect.
On this basis, the circuit can also include communication interface 106, be based on this, the method can also include: benefit
Second current comparator 104 is written into the threshold current with communication interface 106.
In the present example embodiment, described by interface 106 can be I2C (Inter-Integrated
Circuit) interface.The writing mode of the threshold voltage may include the modes such as external burning, and the present exemplary embodiment is to this
It is not particularly limited.The second current comparator 104 is written into threshold current using communication interface 106, allows user according to working as
Threshold current is written in preceding tool situation, even if threshold current is adjustable, and then meets the needs of heterogenous.
This example embodiment also provides a kind of display device, including above-mentioned current foldback circuit.The display device packet
It includes: multi-strip scanning line, for providing scanning signal；Multiple data lines, for providing data-signal；Multiple pixel-driving circuits,
It is electrically connected to above-mentioned scan line and data line；Multiple GOA circuits, for providing scanning signal to scan line；Overcurrent protection electricity
Road is electrically connected multiple GOA circuits, wherein the current foldback circuit is above-mentioned any in this illustrative embodiment
Middle current foldback circuit.Wherein, the display device for example may include mobile phone, tablet computer, television set, laptop,
Any products or components having a display function such as Digital Frame, navigator.
It should be understood that the detail of each modular unit is in corresponding overcurrent protection electricity in the display device
It is described in detail in road, therefore which is not described herein again.
It should be noted that although being referred to several modules or list for acting the equipment executed in the above detailed description
Member, but this division is not enforceable.In fact, according to embodiment of the present disclosure, it is above-described two or more
Module or the feature and function of unit can embody in a module or unit.Conversely, an above-described mould
The feature and function of block or unit can be to be embodied by multiple modules or unit with further division.
In addition, although describing each step of method in the disclosure in the accompanying drawings with particular order, this does not really want
These steps must be executed in this particular order by asking or implying, or having to carry out step shown in whole could realize
Desired result.Additional or alternative, it is convenient to omit multiple steps are merged into a step and executed by certain steps, and/
Or a step is decomposed into execution of multiple steps etc..
Those skilled in the art after considering the specification and implementing the invention disclosed here, will readily occur to its of the disclosure
Its embodiment.This application is intended to cover any variations, uses, or adaptations of the disclosure, these modifications, purposes or
Person's adaptive change follows the general principles of this disclosure and including the undocumented common knowledge in the art of the disclosure
Or conventional techniques.The description and examples are only to be considered as illustrative, and the true scope and spirit of the disclosure are by appended
Claim is pointed out.
Claims (10)
1. a kind of current foldback circuit characterized by comprising
Operational amplifier, first end connects first node, second end connects second node, and third end connects fourth node；
The first transistor connects the fourth node, is connected for responding the signal of the fourth node, and in the first power supply
Electric current is exported to third node under the action of signal；
Current sensor connects the output end of the third node, the current foldback circuit, for third described in real-time detection
The electric current of node；
First current comparator connects the current sensor, for obtaining the third section of current sensor detection in real time
The electric current of point, and generated when the difference of the electric current of the third node at current time and last moment is more than a preset difference value
First comparison result, and generate feedback current；
First current source connects first current comparator and second node, for obtaining first comparison result, and root
The first electric current is inputted to the second node according to first comparison result；
Second current comparator connects first current comparator and current sensor, for obtaining the current sensor
Detection the third node electric current and the feedback current, and according to the electric current of the third node, the feedback current,
Threshold current and a detecting time generate the second comparison result；
Second current source connects second current comparator and the 5th node, for obtaining second comparison result, and root
The second electric current is inputted to the 5th node according to second comparison result；
Second transistor connects the 5th node, is connected for responding the signal of the 5th node, makes the third section
The electric current of point is transmitted to internal ground wire along the second transistor；
First resistor is connected between the input terminal of the current foldback circuit and the first node；
Second resistance is connected between the first node and the third node；
3rd resistor, first end connect the second node, and second end receives second source signal.
2. current foldback circuit according to claim 1, which is characterized in that
The first transistor, control terminal connect the fourth node, and first end receives first power supply signal, and second end connects
Connect the third node；
The current sensor, first end connect the third node, and second end connects the output end of the current foldback circuit；
First current comparator, first end connect the third end of the current sensor；
First current source, first end connect the second end of first current comparator, and second end connects second section
Point；
Second current comparator, first end connect first current comparator third end and the current sensor
Third end；
Second current source, first end connect the second end of second current comparator, and second end connects described Section five
Point；
The second transistor, control terminal connect the 5th node, and first end connects the internal ground wire, and second end connects institute
State third node.
3. current foldback circuit according to claim 1 or 2, which is characterized in that the circuit further includes communication interface,
In:
The communication interface connects the third end of second current comparator, for the threshold current to be written described second
Current comparator.
4. current foldback circuit according to claim 3, which is characterized in that the circuit further includes the 4th resistance and the 5th
Resistance, in which:
4th resistance is connected between the second node and the second end of first current source；
5th resistance is connected between the third node and the internal ground wire.
5. current foldback circuit according to claim 4, which is characterized in that the circuit further includes the 6th resistance and the 7th
Resistance, in which:
6th resistance is connected between the 5th node and the control terminal of the second transistor；
7th resistance, is connected between the third end of the operational amplifier and the fourth node.
6. current foldback circuit according to claim 1, which is characterized in that the generation feedback current includes:
The feedback current is calculated according to following formula:
Wherein, IfFor the feedback current, IjFor the electric current of the input terminal under non-initial state, I0For under original state
The electric current of the input terminal, V0For the voltage of the input terminal, IaFor the electric current in the 3rd resistor under non-initial state,
IbFor the electric current in the 3rd resistor under original state, R3For the resistance value of the 3rd resistor, R1For the first resistor
Resistance value.
7. current foldback circuit according to claim 1, which is characterized in that the electric current according to the third node,
The feedback current, threshold current and a detecting time generate the second comparison result and include:
By the sum of the electric current of the third node and described feedback current compared with the threshold current, and in the third node
Electric current and the sum of feedback current when being greater than duration of the threshold current and being more than the detecting time, generation second
Comparison result.
8. a kind of over-current protection method, for driving current foldback circuit described in claim 1 characterized by comprising
Input signal is inputted to the input terminal of current foldback circuit, so that the input signal passes through first resistor and second resistance
It is transmitted to third node；
Pass through the electric current of third node described in current sensor real-time detection；
It obtains the electric current of the third node of the current sensor detection in real time using the first current comparator, and calculates and work as
The difference of the electric current of the third node at preceding moment and last moment, and when the difference is more than a preset difference value, it generates
First comparison result, and generate feedback current；
First comparison result is obtained by the first current source, and is inputted according to first comparison result to the second node
First electric current, to change the voltage of the third node according to first electric current, operational amplifier, the first transistor；
Control second current comparator obtain in real time current sensor detection the third node electric current and
The feedback current, and the sum of the electric current of the third node and the feedback current be greater than the threshold current it is lasting when
Between be more than detecting the time when, generate the second comparison result；
The second electric current is inputted to the 5th node according to second comparison result by the second current source；
By the second current lead-through second transistor, the electric current of the third node is transmitted to along the second transistor
Internal ground wire.
9. over-current protection method according to claim 8, which is characterized in that the current foldback circuit further includes that communication connects
Mouthful；The method also includes:
Second current comparator is written into the threshold current using the communication interface.
10. a kind of display device, which is characterized in that including the electricity of overcurrent protection described in any one of the claims 1~7
Road.
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| CN201810717527.4A CN108599096B (en) | 2018-07-03 | 2018-07-03 | Current foldback circuit and method, display device |
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| CN201810717527.4A CN108599096B (en) | 2018-07-03 | 2018-07-03 | Current foldback circuit and method, display device |
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| CN109713637B (en) * | 2018-12-27 | 2020-09-15 | 惠科股份有限公司 | Overcurrent protection method, overcurrent protection circuit and display device |
| CN110460016B (en) * | 2019-06-10 | 2022-07-08 | 惠科股份有限公司 | Overcurrent protection circuit, driving method of overcurrent protection circuit and display device |
| CN111627376B (en) | 2020-06-17 | 2021-11-30 | 合肥鑫晟光电科技有限公司 | Overcurrent protection circuit, display device, driving circuit of display device and overcurrent protection method |
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| CN1815838A (en) * | 2005-02-03 | 2006-08-09 | 昂宝电子（上海）有限公司 | Multi-threshold over-curreut protection system and method for switch powersupply converter |
| KR20140054754A (en) * | 2012-10-29 | 2014-05-09 | 단국대학교 산학협력단 | Over current protection circuit |
| CN107085448A (en) * | 2017-06-26 | 2017-08-22 | 中国电子科技集团公司第五十八研究所 | Low pressure difference linear voltage regulator LDO circuit comprising overcurrent protection |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1815838A (en) * | 2005-02-03 | 2006-08-09 | 昂宝电子（上海）有限公司 | Multi-threshold over-curreut protection system and method for switch powersupply converter |
| KR20140054754A (en) * | 2012-10-29 | 2014-05-09 | 단국대학교 산학협력단 | Over current protection circuit |
| CN107085448A (en) * | 2017-06-26 | 2017-08-22 | 中国电子科技集团公司第五十八研究所 | Low pressure difference linear voltage regulator LDO circuit comprising overcurrent protection |
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