CN105304047A - Protection circuit and liquid crystal display with the same - Google Patents
Protection circuit and liquid crystal display with the same Download PDFInfo
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- CN105304047A CN105304047A CN201510799376.8A CN201510799376A CN105304047A CN 105304047 A CN105304047 A CN 105304047A CN 201510799376 A CN201510799376 A CN 201510799376A CN 105304047 A CN105304047 A CN 105304047A
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- management chip
- protection circuit
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Abstract
The invention provides a protection circuit used for a liquid crystal display. The liquid crystal display comprises a power management chip and load connected with the power management chip. The power management chip provides driving voltage to the load. The protection circuit is connected between the power management chip and the load. The protection circuit also comprises a control module which is used for detecting output current of the power management chip and closing the power management chip when the output current exceeds the preset current threshold. The invention also provides the liquid crystal display with the protection circuit. The protection circuit has an over-current protection function and can effectively protect the liquid crystal display against damage caused by excessive current.
Description
Technical field
The present invention relates to field of liquid crystal display, especially relate to a kind of protection circuit and there is the liquid crystal display of this protection circuit.
Background technology
The protection circuit of the part driving voltage VGH of the power management chip of existing liquid crystal display only has under-voltage protection function; not there is excess current protective function; therefore; work as circuit abnormal; when there is the impact of instantaneous large-current as short circuit, module corresponding to this power management chip may be caused to burn, power unit disabler; thus there is blank screen phenomenon, make display panel damage and cannot recover.
Summary of the invention
The invention provides a kind of protection circuit and have the liquid crystal display of this protection circuit, it has excess current protective function, can effectively avoid liquid crystal display to damage because electric current is excessive.
One aspect of the present invention provides a kind of protection circuit; it is for liquid crystal display; the load that this liquid crystal display comprises power management chip and is connected with this power management chip; this power management chip provides driving voltage to this load; this protection circuit is connected between this power management chip and this load, and this protection circuit comprises control module, and this control module detects the output current of this power management chip; and when it exceedes default current threshold, close this power management chip.
Wherein, this control module comprises the first switch and second switch, and when the electric current of this power management chip exceedes default current threshold, this first switch and this second switch conducting, to close this power management chip.
Wherein, this first switch is NPN type triode, and this second switch is PNP type triode, and the collector of this first switch is connected with this power management chip, and control it and open and close, grounded emitter, base stage is through the first resistance eutral grounding; The emitter of this second switch is connected with this power management chip, detects its output current, and collector is connected to the base stage of this first switch through the second resistance, and base stage is connected to this load.
Wherein, this protection circuit also comprises the resistive module be connected with this control module, and this resistive module arranges the size of this current threshold by the size of adjusting resistance value.
Wherein, this resistive module comprises main resistor and some resistance units, each resistance unit comprises basic resistance and gauge tap, can be in parallel with this main resistor by the basic resistance of correspondence by controlling each gauge tap, regulates the size of the resistance value of this resistive module.
Wherein, this gauge tap is N-type metal-oxide-semiconductor, and the drain electrode of the gauge tap of each resistance unit and source electrode are connected to the two ends of this basic resistance, in parallel with main resistor after every two resistance units series connection.
Wherein, the source electrode of one of them gauge tap of the resistance unit of every two series connection is connected with the drain electrode of another gauge tap, and the source electrode of the drain electrode of one of them gauge tap and another gauge tap is connected to the two ends of main resistor respectively.
The present invention provides a kind of liquid crystal display on the other hand; it comprises power management chip, the load be connected with this power management chip and the protection circuit be connected between this power management chip and this load; this power management chip provides driving voltage to this load; this protection circuit is connected between this power management chip and this load; this protection circuit comprises control module; this control module detects the output current of this power management chip; and when it exceedes default current threshold, close this power management chip.
Wherein, this power management chip comprises output pin and enable pin; this protection circuit is connected with this output pin and this enable pin, and detects this power management chip output current by this output pin, is closed by this power management chip by this enable pin.
Wherein, this liquid crystal display also comprises micro-control unit, and this micro-control unit is connected with this protection circuit, can arrange the size of the current threshold of this protection circuit.
Compared to prior art; the protection circuit of the liquid crystal display described in the embodiment of the present invention is in circuit abnormal; as short circuit there is instantaneous large-current and exceed protection circuit preset current threshold time; even if powered-down managing chip, thus liquid crystal display is effectively avoided to damage because electric current is excessive.In addition, MCU can regulate the size of current threshold, and therefore, this protection circuit has more dirigibility and practicality.
Accompanying drawing explanation
In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, be briefly described to the accompanying drawing used required in embodiment or description of the prior art below, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these accompanying drawings.
Fig. 1 is the partial circuit figure with the liquid crystal display of protection circuit of embodiments of the invention.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, be clearly and completely described the technical scheme in the embodiment of the present invention, obviously, described embodiment is only the present invention's part embodiment, instead of whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtained under creative work prerequisite, belong to the scope of protection of the invention.
In addition, the explanation of following embodiment is with reference to additional diagram, can in order to the specific embodiment implemented in order to illustrate the present invention.The direction term mentioned in the present invention, such as, " on ", D score, "front", "rear", "left", "right", " interior ", " outward ", " side " etc., it is only the direction with reference to annexed drawings, therefore, the direction term used be in order to better, be illustrated more clearly in and understand the present invention, instead of instruction or infer the device of indication or element must have specific orientation, with specific azimuth configuration and operation, therefore can not be interpreted as limitation of the present invention.
In describing the invention, it should be noted that, unless otherwise clearly defined and limited, term " installation ", " being connected ", " connection " should be interpreted broadly, and such as, can be fixedly connected with, also can be removably connect, or connect integratedly; It can be mechanical connection; Can be directly be connected, also indirectly can be connected by intermediary, can be the connection of two element internals.For the ordinary skill in the art, concrete condition above-mentioned term concrete meaning in the present invention can be understood.
In addition, in describing the invention, except as otherwise noted, the implication of " multiple " is two or more.If there is the term of " operation " in this instructions, it not only refers to independently operation, when cannot clearly distinguish with other operation, as long as the effect that can realize desired by this operation is then also included within this term.In addition, refer to by the numerical range that " ~ " 0 represents the scope that the numerical value recorded before and after " ~ " is included as minimum value and maximal value in this instructions.In the accompanying drawings, the unit that structure is similar or identical represents with identical label.
Refer to Fig. 1, Fig. 1 is the partial circuit figure with the liquid crystal display of protection circuit of the present invention.As shown in Figure 1, this liquid crystal display 100 comprises power management chip 10, load 30, protection circuit 50 and micro-control unit (MicrocontrollerUnit, MCU) 70.This power management chip 10 is connected to this load 30 through this protection circuit 50, and this micro-control unit 70 is connected with this protection circuit 50.This power management chip 10 provides driving voltage to this load 30, and this protection circuit 50 detects the output current of power management chip 10, and when it exceedes default current threshold, closes this power management chip 10, to carry out overcurrent protection.This MCU70 is used for arranging the size of the current threshold preset of this protection circuit 50, to meet different protection demands.
This power management chip 10 comprises output pin VGH and enable pin En.This output pin VGH is connected, for outputting drive voltage with this load 30 through this protection circuit 50.This Enable Pin pin En is connected with this protection circuit 50, for when the electric current of output pin VGH exceedes default current threshold, closes this power management chip 10, to provide overcurrent protection to it.In this preferred embodiment, when this power management chip 10 normally works, this enable pin En is high level, when this enable pin En is set to low level, this power management chip 10 is closed, and restart this power management chip 10, this enable pin En reverts to high level.
This protection circuit 50 comprises control module 51 and coupled resistive module 53.This control module 51 comprises the first switch T1 and second switch T2, and in this preferred embodiment, this first switch T1 is NPN type triode, and this second switch T2 is PNP type triode.The collector C of this first switch T1 is connected with this enable pin En, controls the open and close of this power management chip 10, emitter E ground connection, and base stage B is through the first resistance R1 ground connection.The emitter E of this second switch T2 is connected with this output pin VGH, detects its output current, and collector C is connected to the base stage B of this first switch T1 through the second resistance R2, and base stage B is connected to load 30.The original state of this first switch T1 and this second switch T2 is cut-off state; when the electric current of output terminal VGH exceedes default current threshold; this the first switch T1 and this second switch T2 conducting; the enable pin En of power management chip 10 is made to be converted to low level by high level; thus power management chip 10 is closed, play the effect of overcurrent protection.
This resistive module 53 comprises main resistor Rm and some resistance units 531.Between the emitter E that this main resistor R0 is connected in parallel to second switch T2 and base stage B.In this preferred embodiment, this resistive module 531 comprises 6 resistance units 531, each resistance unit 531 comprises basic resistance R0 and gauge tap Q, in this preferred embodiment, this gauge tap Q is N-type metal-oxide-semiconductor, its drain D and source S are connected to the two ends of this basic resistance R0, and grid G is connected with MCU70.Every two resistance units 531 are in parallel with main resistor R0 after connecting, particularly, the source S of one of them gauge tap Q of the resistance unit 531 of every two series connection is connected with the drain D of another gauge tap Q, and the source S of the drain D of one of them gauge tap Q and another gauge tap Q is connected to the two ends of main resistor Rm respectively.
This protection circuit 50 also comprises electric capacity C1, and this electric capacity C1 is connected in parallel to resistive module 53, in order to filtering noise information.
This MCU70 comprises some control pins corresponding with resistance unit 531, in this preferred embodiment, have 6 and control pin CK1 to CK6, be connected with the grid G of the gauge tap Q of 6 resistance units 531 respectively, corresponding basic resistance R0 access resistive module 53 by the conducting exporting low and high level and carry out gauge tap Q with cut-off state and regulates its resistance value by MCU70, thus sets the threshold value of the electric current of correspondence.Example 70 is when MCU70 output is 111111, all gauge tap Q all locate conducting state, the resistance value Rs of resistive module 53 is the resistance value of main resistor Rm, when MCU70 export be 011111 time, based on the resistance value Rs of resistive module 53 resistance R0 in parallel with main resistor Rm after resistance value.Obviously, resistance unit 531 can increase and decrease according to the demand of reality with the concrete number of the control pin of MCU70, and correspondingly, resistance unit 531 can change according to the circuit design of reality with the connected mode of main resistor Rm.
When liquid crystal display 100 of the present invention works, the enable pin En of this power management chip 10 is high level, and output pin VGH provides driving voltage to load 30.Work as circuit abnormal; as short circuit occur that instantaneous large-current exceedes the current threshold that protection circuit 50 presets time; this the first switch T1 and second switch T2 conducting; this enable pin En is converted to low level by high level; thus power management chip 10 is closed; to carry out overcurrent protection, meanwhile, basic resistance R0 is accessed resistive module 53 and sets this current threshold by the conducting and cut-off state of this MCU70 also by controlling gauge tap Q.
In sum; the protection circuit 10 of the liquid crystal display 100 described in the embodiment of the present invention is in circuit abnormal; when there is instantaneous large-current as short circuit and exceed the current threshold that protection circuit 50 presets; even if powered-down managing chip 10, thus liquid crystal display 100 is effectively avoided to damage because electric current is excessive.In addition, MCU70 can regulate the size of current threshold, and therefore, this protection circuit 50 has more dirigibility and practicality.
In the description of this instructions, specific features, structure, material or feature that the description of reference term " embodiment ", " some embodiments ", " example ", " concrete example " or " some examples " etc. means to describe in conjunction with this embodiment or example are contained at least one embodiment of the present invention or example.In this manual, identical embodiment or example are not necessarily referred to the schematic representation of above-mentioned term.And the specific features of description, structure, material or feature can combine in an appropriate manner in any one or more embodiment or example.
Above disclosedly be only a kind of preferred embodiment of the present invention, certainly the interest field of the present invention can not be limited with this, one of ordinary skill in the art will appreciate that all or part of flow process realizing above-described embodiment, and according to the equivalent variations that the claims in the present invention are done, still belong to the scope that invention is contained.
Claims (10)
1. a protection circuit; it is for liquid crystal display; the load that this liquid crystal display comprises power management chip and is connected with this power management chip; this power management chip provides driving voltage to this load, it is characterized in that, this protection circuit is connected between this power management chip and this load; this protection circuit comprises control module; this control module detects the output current of this power management chip, and when it exceedes default current threshold, closes this power management chip.
2. protection circuit as claimed in claim 1; it is characterized in that, this control module comprises the first switch and second switch, when the electric current of this power management chip exceedes default current threshold; this first switch and this second switch conducting, to close this power management chip.
3. protection circuit as claimed in claim 2, it is characterized in that, this first switch is NPN type triode, this second switch is PNP type triode, and the collector of this first switch is connected with this power management chip, controls it and opens and closes, grounded emitter, base stage is through the first resistance eutral grounding; The emitter of this second switch is connected with this power management chip, detects its output current, and collector is connected to the base stage of this first switch through the second resistance, and base stage is connected to this load.
4. protection circuit as claimed in claim 1, it is characterized in that, this protection circuit also comprises the resistive module be connected with this control module, and this resistive module arranges the size of this current threshold by the size of adjusting resistance value.
5. protection circuit as claimed in claim 4; it is characterized in that; this resistive module comprises main resistor and some resistance units; each resistance unit comprises basic resistance and gauge tap; can be in parallel with this main resistor by the basic resistance of correspondence by controlling each gauge tap, regulate the size of the resistance value of this resistive module.
6. protective resistance as claimed in claim 5, it is characterized in that, this gauge tap is N-type metal-oxide-semiconductor, and the drain electrode of the gauge tap of each resistance unit and source electrode are connected to the two ends of this basic resistance, in parallel with main resistor after every two resistance units series connection.
7. protective resistance as claimed in claim 6; it is characterized in that; the source electrode of one of them gauge tap of the resistance unit of every two series connection is connected with the drain electrode of another gauge tap, and the source electrode of the drain electrode of one of them gauge tap and another gauge tap is connected to the two ends of main resistor respectively.
8. a liquid crystal display; it comprises power management chip, the load be connected with this power management chip and the protection circuit be connected between this power management chip and this load; this power management chip provides driving voltage to this load; this protection circuit is connected between this power management chip and this load; it is characterized in that, this protection circuit is the protection circuit in claim 1-6 item described in any one.
9. liquid crystal display as claimed in claim 8; it is characterized in that; this power management chip comprises output pin and enable pin; this protection circuit is connected with this output pin and this enable pin; and detect this power management chip output current by this output pin, by this enable pin, this power management chip is closed.
10. liquid crystal display as claimed in claim 8, it is characterized in that, this liquid crystal display also comprises micro-control unit, and this micro-control unit is connected with this protection circuit, can arrange the size of the current threshold of this protection circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510799376.8A CN105304047B (en) | 2015-11-19 | 2015-11-19 | Protect circuit and the liquid crystal display with the protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510799376.8A CN105304047B (en) | 2015-11-19 | 2015-11-19 | Protect circuit and the liquid crystal display with the protection circuit |
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| Publication Number | Publication Date |
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| CN105304047A true CN105304047A (en) | 2016-02-03 |
| CN105304047B CN105304047B (en) | 2018-07-03 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201510799376.8A Active CN105304047B (en) | 2015-11-19 | 2015-11-19 | Protect circuit and the liquid crystal display with the protection circuit |
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| CN (1) | CN105304047B (en) |
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| CN106707590A (en) * | 2017-02-27 | 2017-05-24 | 深圳市华星光电技术有限公司 | Display panel over-temperature protection system and display panel over-temperature protection method |
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| CN110010099A (en) * | 2019-04-29 | 2019-07-12 | 深圳市华星光电技术有限公司 | A kind of voltage regulator circuit, control method and display device |
| CN110890052A (en) * | 2019-11-29 | 2020-03-17 | Tcl华星光电技术有限公司 | Driving circuit, driving method and display device |
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|---|---|
| CN105304047B (en) | 2018-07-03 |
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