CN109272946A - A kind of backlight control circuit and liquid crystal display device - Google Patents
A kind of backlight control circuit and liquid crystal display device Download PDFInfo
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- CN109272946A CN109272946A CN201811366972.7A CN201811366972A CN109272946A CN 109272946 A CN109272946 A CN 109272946A CN 201811366972 A CN201811366972 A CN 201811366972A CN 109272946 A CN109272946 A CN 109272946A
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- backlight
- signal
- switch
- control signal
- microcontroller
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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
- G09G3/3406—Control of illumination source
-
- 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
Abstract
The present invention provides a kind of backlight control circuit and liquid crystal display device, comprising: microcontroller, LED driver and logic module；Wherein logic module includes partial pressure unit, isolated location；Partial pressure unit includes first resistor and second resistance, and isolated location includes switch tube elements, pull down resistor；Switching tube elements includes control terminal, the first path terminal and alternate path end.Wherein, the logic module is when receiving effective enable signal, if the level of the received width viewing angle control signal of microcontroller changes, then the level of the received switch control signal of the logic module also changes, so that the backlight control signal of logic module output is from effectively becoming invalid, so that the LED driver stops driving backlight.Backlight control circuit and liquid crystal display device disclosed by the invention can control backlight closing when switching width visual angle, while enable signal can not be directly entered microcontroller generation electric current and microcontroller is caused to fail.
Description
Technical field
The present invention relates to technical field of liquid crystal display more particularly to a kind of backlight control circuits and liquid crystal display device.
Background technique
Since liquid crystal display device has many advantages, such as frivolous, energy saving, Low emissivity, do not flash, it is now widely used for
The electronic equipments such as TV, computer, mobile phone, digital camera.Liquid crystal display device is broadly divided into three types currently on the market: plane
(In-Plane Switching, the IPS) type of conversion, vertical orientation (Vertical Alignment, VA) type and twisted-nematic
(Twisted Nematic, TN) type or super twisted nematic (Super Twisted Nematic, STN) type.Mix visual angle
(Hybrid Viewing Angle, HVA) type is improved a kind of liquid crystal display device on the basis of plane conversion type.HVA
Type liquid crystal display device be divided into wide viewing angle (Wide Viewing, WVA) mode and narrow viewing angle (Narrow Viewing Angle,
NVA) mode.
Of short duration closing backlight is needed when user switches between wide and narrow viewing angle modes, to block width switching wink
Between unstable state, the connection processing in existing design scheme for enable signal and microcontroller is to pass through enable signal
Resistance and diode are directly connected to microcontroller I/O port.
Fig. 1 shows the structural schematic diagram of microcontroller in the prior art, as shown in Figure 1, in the prior art, a side
Face, when system power supply Vin does not power and when enable signal EN power supply 3.3V, the supply voltage DVCC of microcontroller is 0V, micro-control
Diode inside device processed is switched on, and enable signal EN can generate electric leakage to microcontroller, will affect microcontroller for a long time
Service life causes microcontroller to fail；On the other hand, the electricity of the microcontroller input/output end port in existing design scheme
Pressure request must not be higher than its supply voltage 0.3V, but backlight module lighting different pictures power consumption is different, and line loss is not also identical, can
There can be actual power low voltage (being assumed to be 3.0V) on backlight module, and when the voltage of enable signal maintains 3.3V constant,
Then the possibility beyond 0.3V will be present in microcontroller input/output end port voltage and supply voltage, does not meet microcontroller specification
Book requirement, may bring control unknown risks.
Summary of the invention
The main purpose of the present invention is to provide a kind of backlight control circuit and liquid crystal display devices, can regard in width
Backlight is closed when the pattern switching of angle, while guaranteeing that enable signal can not be directly entered microcontroller and generate leakage current, is avoided micro-
The risk of controller failure, improves the stability of circuit.
To achieve the above object, first aspect of the embodiment of the present invention provides a kind of backlight control circuit, comprising: microcontroller
Device, including width viewing angle control signal input part, switch control signal output end；LED driver, including backlight control signal are defeated
Enter end；Logic module, the logic module include partial pressure unit, isolated location；The partial pressure unit includes first resistor and
Two resistance, the first end of the first resistor receive enable signal, the second end of the first resistor and the LED driver
Backlight enable signal input terminal is connected, and is grounded by the second resistance；The isolated location includes switch tube elements, drop-down
Resistance, the switch tube elements include control terminal, the first path terminal and alternate path end, the control terminal of the switch tube elements with
The switch control signal output end of the microcontroller is connected, the first path terminal and the first resistor of the switch tube elements
Second end be connected, the alternate path end ground connection of the switch tube elements, the pull down resistor is located at the switch tube elements
Between control terminal and ground；Wherein, the logic module is when receiving effective enable signal, if the microcontroller is received
The level of width viewing angle control signal changes, then the level of the received switch control signal of the logic module is also sent out
Changing, so that the backlight control signal of logic module output is from effectively becoming invalid, so that the LED drives
Device stops driving backlight.
Further, if the enable signal is useful signal, the switch control signal is invalid signals, the switch
Tube elements are closed and then the backlight enable signal is effective and control backlight unlatching；
If the enable signal is useful signal, the switch control signal is useful signal, and the switch tube elements are led
The logical and then described backlight enable signal is invalid and controls backlight closing.
Further, the useful signal is high level signal or low level signal.
Further, when the width viewing angle control signal converts, the switch control signal generates and maintains 100-
The useful signal of 200ms, so that the backlight control signal of logic module output generates and maintains the invalid letter of 100-200ms
Number, so that the LED driver stops driving backlight in 100-200ms.
Further, the switch tube elements are NMOS tube or PMOS tube or triode.
Further, the switch control signal output end of the microcontroller is input/output end port.
Further, the backlight control circuit further include: 3rd resistor, the 3rd resistor are located at switch control
Between signal output end processed and the switch tube elements control terminal.
Further, the backlight control circuit further include: capacitor, the capacitor are in parallel with the pull down resistor.
Further, the backlight control circuit further includes connector, the connector provide the enable signal and
The width viewing angle control signal.
In addition, to achieve the above object, second aspect of the embodiment of the present invention provides a kind of liquid crystal display device, the liquid crystal
Display device includes backlight control circuit described in backlight and first aspect.
Backlight control circuit and liquid crystal display device provided by the invention can be in width by the way that logic module is arranged
Field-of-view mode closes backlight when switching, while isolated location is arranged in logic module, and the switch tube elements in isolated location can
Guarantee that enable signal can not be directly entered microcontroller and generate leakage current, avoids microcontroller from failing, moreover it is possible to guarantee in backlight mould
Group lighting different pictures power consumption is different, in the case that line loss is different, the relatively low bring control unknown risks of the supply voltage of microcontroller,
So that the requirement of the voltage of the input/output end port of microcontroller book up to specification.In addition, the pull down resistor in isolated location is not
It is only capable of giving switch one stable state of tube elements in a flash what mould group powered on, moreover it is possible to avoid the parasitism due to switching tube elements
The influence of capacitor, and the case where cause the switch control signal output end of microcontroller to be coupled and draw high, guarantee microcontroller
The level of its switch controlled signal output port is low level when not working.Therefore the present invention significantly improves backlight
The stability of source controller circuitry, and then improve the quality of liquid crystal display device.
Detailed description of the invention
By referring to the drawings to the description of the embodiment of the present invention, above-mentioned and other purposes of the invention, feature and
Advantage will be apparent from.
Fig. 1 shows the structural schematic diagram of microcontroller in the prior art；
Fig. 2 shows the backlight control circuit structural schematic diagrams of first embodiment of the invention；
Fig. 3 shows the signal in the backlight control circuit as shown in Figure 2 of first embodiment and cuts at progress width visual angle
Logic timing figure when changing；
Fig. 4 shows the backlight control circuit structural schematic diagram of second embodiment of the invention；
Fig. 5 shows the signal in the backlight control circuit as shown in Figure 4 of second embodiment and cuts at progress width visual angle
Logic timing figure when changing.
Specific embodiment
Hereinafter reference will be made to the drawings, and the present invention will be described in more detail.In various figures, identical element is using similar attached
Icon is remembered to indicate.For the sake of clarity, the various pieces in attached drawing are not necessarily to scale.In addition, may not show in figure
Certain well known parts out.
Many specific details of the invention, such as structure, material, size, the processing work of device is described hereinafter
Skill and technology, to be more clearly understood that the present invention.But it just as the skilled person will understand, can not press
The present invention is realized according to these specific details.
First embodiment
Fig. 2 shows the backlight control circuit structural schematic diagram of first embodiment of the invention, Fig. 3 shows first embodiment
Logic timing figure of the signal when carrying out width view angle switch in backlight control circuit as shown in Figure 2, as shown in Fig. 2,
Backlight control circuit of the invention includes microcontroller 11, LED driver 12 and logic module 13.Microcontroller 11 includes width
Narrow viewing angle control signal input, switch control signal output end P1.1.LED driver 12 is inputted including backlight control signal
End.Logic module 13 includes partial pressure unit 131, isolated location 132.
Specifically, partial pressure unit 131 includes first resistor R1 and second resistance R2, and the first end reception of first resistor R1 makes
Energy signal EN, the second end of first resistor R1 is connected with the backlight control signal input terminal of LED driver, and passes through second resistance
R2 ground connection.
Specifically, isolated location 132 includes switch tube elements T1, pull down resistor R4.Switch tube elements T1 include control terminal,
First path terminal and alternate path end switch the control terminal and the switch control signal output end phase of microcontroller 11 of tube elements T1
Even, the first path terminal of switch tube elements T1 is connected with the second end of first resistor R1, switchs the alternate path end of tube elements T1
Ground connection, pull down resistor R4 are located between the control terminal and ground of switch tube elements T1.
In the present embodiment, switch tube elements T1 is preferably N-channel field-effect tube, i.e. NMOS tube.However the present invention is real
Apply that example is without being limited thereto, those skilled in the art can according to need the type for determining switch tube elements, and to the electricity of corresponding signal
It is flat to adjust accordingly.
Wherein, logic module 13 is when receiving effective enable signal EN, if the received width visual angle of microcontroller 11
The level of control signal HVA changes, then the level of the received switch control signal EN_M of logic module 13 also changes,
So that the backlight control signal EN_L that logic module 13 exports is from effectively becoming invalid, so that LED driver stops driving
Dynamic backlight.
In the present embodiment, if enable signal EN is useful signal, switch control signal EN_M is invalid signals, switch
Tube elements T1 is closed and then backlight enable signal EN_L is effective and controls backlight unlatching；
If enable signal EN be useful signal, switch control signal EN_M be useful signal, switch tube elements T1 be connected into
And backlight enable signal EN_L is invalid and controls backlight closing.
Useful signal is different with the switch selection model of tube elements T1 according to LED driver 12 in the present invention, can be height
Level signal or low level signal.
In order to better understand the present invention, specifically, it below in conjunction with Fig. 3, and to switch tube elements T1 as NMOS tube, enables
Signal EN is that high level is effective, and backlight enable signal EN_L is also to be illustrated for high level is effective.
At the A moment, supply voltage Vin is powered on, enable signal EN is high level, the level of width viewing angle control signal HVA
Do not change (width visual angle does not switch over) when, microcontroller 11 switch control signal output end P1.1 output switch
Control signal EN_M is low level, and therefore, NMOS tube T1 is closed, and backlight enable signal EN_L is enabled by first resistor R1
Signal EN is drawn high, and LED driver 12 drives backlight, so that backlight is open state.
At the B moment, the level change of width viewing angle control signal HVA, (width visual angle switches over) is for example such as Fig. 3 institute
That shows becomes high level, the switch control signal of the switch control signal output end P1.1 output of microcontroller 11 from low level
EN_M is high level and maintains 100-200ms, and then NMOS tube T1 is connected, the NMOS that backlight enable signal EN_L passes through conducting
Pipe T1 is pulled low, and LED driver 12 stops driving backlight, and backlight is closed；
At the C moment, width viewing angle control signal HVA is maintained high level (not converting), the switch control of microcontroller 11
Signal output end P1.1 processed exports low level switch control signal EN_M again, and NMOS tube T1 is again switched off, and backlight is enabled
Signal EN_L reverts to high level, and LED driver 12 drives backlight again, and backlight is again turned on.
In addition, logic module 13, when receiving invalid enable signal EN, switch tube elements T1 is regardless of conducting or closes
(i.e. regardless of whether carrying out width view angle switch) is closed, LED driver 12 receives invalid backlight enable signal EN_L, back
Light source is in close state always.
In the present embodiment, the switch control signal output end P1.1 of microcontroller 11 is input/output end port, this reality
Applying and preferably choosing P1.1 stitch in example is switch control signal output end, and defaulting output is low level.
Since in width viewing angle control signal HVA transformation, switch control signal EN_M is generated and is maintained 100-200ms's
High level signal, NMOS tube T1 conducting, enable signal EN is pulled low by the NMOS tube T1 be connected, so that logic module 13 exports
Backlight control signal EN_L be low level signal so that LED driver 12 stops in 100-200ms driving backlight.
When width viewing angle control signal HVA is without transformation, the P1.1 port signal of microcontroller 11 reverts to low level again, thus
NMOS tube T1 is closed, so that backlight control signal EN_L is high level, LED driver 12 continues to drive backlight.Therefore, originally
The backlight source driving circuit of invention can close backlight when wide and narrow viewing angle modes switch, and not cut in wide and narrow viewing angle modes
The normally-open backlight of energy, guarantees the normal work of liquid crystal display device when changing.Moreover, the switching tube member in isolated location 132
Enable signal EN and microcontroller 11 are isolated by part NMOS tube T1, are avoided enable signal EN and are generated to the generation of microcontroller 11
Leakage current is also avoided since backlight module lighting different pictures power consumption is different, practical on backlight module caused by line loss is different
Supply voltage Vin is relatively low, and then unknown brought by the voltage lower than the switch control signal output end P1.1 of microcontroller 11
Risk.Further, since the control terminal and ground of pull down resistor R4 connection NMOS tube T1 of the invention, avoid due to switching tube elements
The influence of the interelectrode capacity of T1, and cause the switch control signal output end P1.1 of microcontroller 11 to be coupled and the feelings drawn high
Condition, the level for further ensuring the switch control signal output end P1.1 when not working of microcontroller 11 is low level, in turn
Guarantee that even if switch control signal output end P1.1 is input/output end port, its voltage will not occur higher than microcontroller
The case where 11 supply voltage DVCC.
Backlight control circuit in the present embodiment can also include 3rd resistor R3, be located at switch control signal and export
Between end and the control terminal of switch tube elements NMOS tube T1, for limit switch control signal output and switch tube elements NMOS
Electric current between the control terminal of pipe T1.
Backlight control circuit further includes capacitor C1, is located at the common node and ground of 3rd resistor R3 and pull down resistor R4
Between, for reducing AC ripple ripple coefficient, smooth direct current output.
In one embodiment, backlight control circuit further includes connector 10, enable signal EN, width viewing angle control letter
Number HVA and supply voltage DVCC is provided by connector 10.
In one embodiment, the port supply voltage DVCC of microcontroller 11 is connected with the port Vin of connector 10.
Backlight control circuit provided in an embodiment of the present invention passes through setting logic module 13 and itself and microcontroller 11
With the connection type of LED driver 12, backlight can be closed when wide and narrow viewing angle modes switch, while logic module 13 is arranged
Isolated location 132, the switch tube elements T1 in isolated location 132 both can guarantee that enable signal EN can not be directly entered microcontroller
11 generate leakage current, and microcontroller 11 is avoided to fail, moreover it is possible to guarantee that line loss is not in backlight module lighting different pictures power consumption difference
With in the case where, the relatively low bring control unknown risks of supply voltage Vin of microcontroller 11 are inputted, so that microcontroller 11 is defeated
Enter/the requirement of the voltage book up to specification of output port P1.1.In addition, pull down resistor R4 in isolated location 132 can not only be
What backlight source driving circuit powered on gives in a flash switch mono- stable state of tube elements T1, moreover it is possible to avoid due to switching tube elements
The influence of the interelectrode capacity of T1, and cause the switch control signal output end P1.1 of microcontroller 11 to be coupled and the feelings drawn high
Condition guarantees that the level of its switch controlled signal output port P1.1 when microcontroller 11 does not work is low level.Therefore, this hair
The bright stability for significantly improving backlight control circuit, and then improve the quality of liquid crystal display device.
Second embodiment
Fig. 4 shows the backlight control circuit structural schematic diagram of second embodiment of the invention, and Fig. 5 shows second embodiment
Logic timing figure of the signal when carrying out width view angle switch in backlight control circuit as shown in Figure 4, as shown in figure 4,
Backlight control circuit in the present embodiment is roughly the same with the backlight control circuit in first embodiment, and difference is this reality
Applying the switch tube elements T1 in example is PMOS tube, the default output level of the switch control signal output end P1.1 of microcontroller 11
For high level.
In the present embodiment, switch tube elements T1 is P-channel field-effect transistor (PEFT) pipe, i.e. PMOS tube.However the embodiment of the present invention is not
It is limited to this, those skilled in the art can according to need the type for determining switch tube elements, and do phase to the level of corresponding signal
It should adjust.
Wherein, logic module 13 is when receiving effective enable signal EN, if the received width visual angle of microcontroller 11
The level of control signal HVA changes, then the level of the received switch control signal EN_M of logic module 13 also changes,
So that the backlight control signal EN_L that logic module 13 exports is from effectively becoming invalid, so that LED driver stops driving
Dynamic backlight.
In the present embodiment, if enable signal EN is useful signal, switch control signal EN_M is invalid signals, switch
Tube elements T1 is closed and then backlight enable signal EN_L is effective and controls backlight unlatching；
If enable signal EN be useful signal, switch control signal EN_M be useful signal, switch tube elements T1 be connected into
And backlight enable signal EN_L is invalid and controls backlight closing.
Useful signal is different with the switch selection model of tube elements T1 according to LED driver 12 in the present invention, can be height
Level signal or low level signal.
In order to better understand the present invention, specifically, it below in conjunction with Fig. 5, and to switch tube elements T1 as PMOS tube, enables
Signal EN is that high level is effective, and backlight enable signal EN_L is also to be illustrated for high level is effective.
At the A moment, supply voltage Vin is powered on, enable signal EN is high level, the level of width viewing angle control signal HVA
Do not change (width visual angle does not switch over) when, microcontroller 11 switch control signal output end P1.1 output switch
Control signal EN_M is high level, and therefore, PMOS tube T1 is closed, and backlight enable signal EN_L is enabled by first resistor R1
Signal EN is drawn high, and LED driver 12 drives backlight, so that backlight is open state.
At the B moment, the level change of width viewing angle control signal HVA, (width visual angle switches over) is for example such as Fig. 5 institute
That shows becomes high level, the switch control signal of the switch control signal output end P1.1 output of microcontroller 11 from low level
EN_M is low level and maintains 100-200ms, and then PMOS tube T1 is connected, the PMOS that backlight enable signal EN_L passes through conducting
Pipe T1 is pulled low, and LED driver 12 stops driving backlight, and backlight is closed；
At the C moment, width viewing angle control signal HVA is maintained high level (not converting), the switch control of microcontroller 11
Signal output end P1.1 processed exports the switch control signal EN_M of high level again, and PMOS tube T1 is again switched off, and backlight is enabled
Signal EN_L reverts to high level, and LED driver 12 drives backlight again, and backlight is again turned on.
In addition, logic module 13, when receiving invalid enable signal EN, switch tube elements T1 is regardless of conducting or closes
(i.e. regardless of whether carrying out width view angle switch) is closed, LED driver 12 receives invalid backlight enable signal EN_L, back
Light source is in close state always.
In the present embodiment, the switch control signal output end P1.1 of microcontroller 11 is input/output end port, this reality
Applying and preferably choosing P1.1 stitch in example is switch control signal output end, and defaulting output is low level.
Since in width viewing angle control signal HVA transformation, switch control signal EN_M is generated and is maintained 100-200ms's
Low level signal, PMOS tube T1 conducting, enable signal EN is pulled low by the PMOS tube T1 be connected, so that logic module 13 exports
Backlight control signal EN_L be low level signal so that LED driver 12 stops in 100-200ms driving backlight.
When width viewing angle control signal HVA is without transformation, the P1.1 port signal of microcontroller 11 reverts to high level again, thus
PMOS tube T1 is closed, so that backlight control signal EN_L is high level, LED driver 12 continues to drive backlight.Therefore, originally
The backlight source driving circuit of invention can close backlight when wide and narrow viewing angle modes switch, and not cut in wide and narrow viewing angle modes
The normally-open backlight of energy, guarantees the normal work of liquid crystal display device when changing.Moreover, the switching tube member in isolated location 132
Enable signal EN and microcontroller 11 are isolated by part PMOS tube T1, are avoided enable signal EN and are generated to the generation of microcontroller 11
Leakage current is also avoided since backlight module lighting different pictures power consumption is different, practical on backlight module caused by line loss is different
Supply voltage Vin is relatively low, and then unknown brought by the voltage lower than the switch control signal output end P1.1 of microcontroller 11
Risk.Further, since the control terminal and ground of pull down resistor R4 connection PMOS tube T1 of the invention, avoid due to switching tube elements
The influence of the interelectrode capacity of T1, and cause the switch control signal output end P1.1 of microcontroller 11 to be coupled and the feelings drawn high
Condition, the level for further ensuring the switch control signal output end P1.1 when not working of microcontroller 11 is low level, in turn
Guarantee that even if switch control signal output end P1.1 is input/output end port, its voltage will not occur higher than microcontroller
The case where 11 supply voltage DVCC.
Backlight control circuit in the present embodiment can also include 3rd resistor R3, be located at switch control signal and export
Between end and the control terminal of switch tube elements PMOS tube T1, for limit switch control signal output and switch tube elements PMOS
Electric current between the control terminal of pipe T1.
Backlight control circuit further includes capacitor C1, is located at the common node and ground of 3rd resistor R3 and pull down resistor R4
Between, for reducing AC ripple ripple coefficient, smooth direct current output.
In one embodiment, backlight control circuit further includes connector 10, enable signal EN, width viewing angle control letter
Number HVA and supply voltage DVCC is provided by connector 10.
In one embodiment, the port supply voltage DVCC of microcontroller 11 is connected with the port Vin of connector 10.
Backlight control circuit provided in an embodiment of the present invention passes through setting logic module 13 and itself and microcontroller 11
With the connection type of LED driver 12, backlight can be closed when wide and narrow viewing angle modes switch, while logic module 13 is arranged
Isolated location 132, the switch tube elements T1 in isolated location 132 both can guarantee that enable signal EN can not be directly entered microcontroller
11 generate leakage current, and microcontroller 11 is avoided to fail, and can guarantee that line loss is not in backlight module lighting different pictures power consumption difference
With in the case where, the relatively low bring control unknown risks of supply voltage Vin of microcontroller 11 are inputted, so that microcontroller 11 is defeated
Enter/the requirement of the voltage book up to specification of output port P1.1.In addition, pull down resistor R4 in isolated location 132 can not only be
What backlight source driving circuit powered on gives in a flash switch mono- stable state of tube elements T1, moreover it is possible to avoid due to switching tube elements
The influence of the interelectrode capacity of T1, and cause the switch control signal output end P1.1 of microcontroller 11 to be coupled and the feelings drawn high
Condition guarantees that the level of its switch controlled signal output port P1.1 when microcontroller 11 does not work is low level.Therefore, this hair
The bright stability for significantly improving backlight control circuit, and then improve the quality of liquid crystal display device.
3rd embodiment
Third embodiment of the invention provides a kind of liquid crystal display device, liquid crystal display device include backlight control module and
Backlight.Wherein, the structure and working principle of backlight control module please refers to the description of above-mentioned backlight control module, herein
It repeats no more.
Backlight control circuit and liquid crystal display device provided by the invention, by setting logic module 13 and its with it is micro-
The connection type of controller 11 and LED driver 12 can close backlight, while logic mould when wide and narrow viewing angle modes switch
Isolated location 132 is arranged in block 13, and the switch tube elements T1 in isolated location 132 both can guarantee that enable signal EN can not be directly entered
Microcontroller 11 generate leakage current, avoid microcontroller 11 fail, moreover it is possible to guarantee backlight module lighting different pictures power consumption not
Together, in the case that line loss is different, the relatively low bring control unknown risks of supply voltage Vin of microcontroller 11 are inputted, so that microcontroller
The requirement of the voltage book up to specification of the input/output end port P1.1 of device 11.In addition, the pull down resistor R4 in isolated location 132
Switch one stable state of tube elements can not only be given in a flash what mould group powered on, moreover it is possible to avoid due to switch tube elements T1's
The influence of parasitic capacitance, and the case where cause the switch control signal output end P1.1 of microcontroller 11 to be coupled and draw high, it protects
The level of its switch controlled signal output port P1.1 is low level when card microcontroller 11 does not work.Therefore the present invention is very big
Degree improves the stability of backlight control circuit, and then improves the quality of liquid crystal display device.
It should be noted that herein, relational terms such as first and second and the like are used merely to a reality
Body or operation are distinguished with another entity or operation, are deposited without necessarily requiring or implying between these entities or operation
In any actual relationship or order or sequence.Moreover, the terms "include", "comprise" or its any other variant are intended to
Non-exclusive inclusion, so that the process, method, article or equipment including a series of elements is not only wanted including those
Element, but also including other elements that are not explicitly listed, or further include for this process, method, article or equipment
Intrinsic element.In the absence of more restrictions, the element limited by sentence "including a ...", it is not excluded that
There is also other identical elements in process, method, article or equipment including the element.
It is as described above according to the embodiment of the present invention, these embodiments there is no detailed descriptionthe thus details, also not
Limiting the invention is only the specific embodiment.Obviously, as described above, can make many modifications and variations.This explanation
These embodiments are chosen and specifically described to book, is to cough up and preferably explaining the principle of the present invention and practical application, thus belonging to making
Technical field technical staff can be used using modification of the invention and on the basis of the present invention well.The present invention is only by right
The limitation of claim and its full scope and equivalent.
Claims (10)
1. a kind of backlight control circuit characterized by comprising
Microcontroller, including width viewing angle control signal input part, switch control signal output end；
LED driver, including backlight control signal input terminal；
Logic module, the logic module include partial pressure unit, isolated location；
The partial pressure unit includes first resistor and second resistance, and the first end of the first resistor receives enable signal, described
The second end of first resistor is connected with the backlight enable signal input terminal of the LED driver, and is connect by the second resistance
Ground；
The isolated location include switch tube elements, pull down resistor, the switch tube elements include control terminal, the first path terminal and
The control terminal at alternate path end, the switch tube elements is connected with the switch control signal output end of the microcontroller, described
First path terminal of switch tube elements is connected with the second end of the first resistor, the alternate path termination of the switch tube elements
Ground, the pull down resistor are located between the control terminal and ground of the switch tube elements；
Wherein, the logic module is when receiving effective enable signal, if the received width visual angle control of the microcontroller
The level of signal processed changes, then the level of the received switch control signal of the logic module also changes, from
And make the backlight control signal of the logic module output from effectively becoming invalid, so that the LED driver stops driving
Dynamic backlight.
2. backlight control circuit according to claim 1, which is characterized in that
If the enable signal be useful signal, the switch control signal be invalid signals, the switch tube elements close into
And the backlight enable signal is effective and controls backlight unlatching；
If the enable signal be useful signal, the switch control signal be useful signal, the switching tube element conductive into
And the backlight enable signal is invalid and controls backlight closing.
3. backlight control circuit according to claim 2, which is characterized in that
The useful signal is high level signal or low level signal.
4. backlight control circuit according to claim 2, which is characterized in that
In width viewing angle control signal transformation, the switch control signal generates and maintains effective letter of 100-200ms
Number, so that the backlight control signal of logic module output generates and maintains the invalid signals of 100-200ms, so that described
LED driver stops driving backlight in 100-200ms.
5. backlight control circuit according to claim 1, which is characterized in that
The switch tube elements are NMOS tube or PMOS tube or triode.
6. backlight control circuit according to claim 1, which is characterized in that
The switch control signal output end of the microcontroller is input/output end port.
7. backlight control circuit according to claim 1, which is characterized in that the backlight control circuit further include:
3rd resistor, the 3rd resistor is between the switch control signal output end and the switch tube elements control terminal.
8. backlight control circuit according to claim 7, which is characterized in that the backlight control circuit further include:
Capacitor, the capacitor is between the 3rd resistor and the common node and ground of the pull down resistor.
9. backlight control circuit according to claim 1, which is characterized in that the backlight control circuit further includes connecting
Device is connect, the connector provides the enable signal and the width viewing angle control signal.
10. a kind of liquid crystal display device characterized by comprising
Backlight control circuit and backlight as described in any one of claim 1 to 9.
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| CN201811366972.7A CN109272946B (en) | 2018-11-16 | 2018-11-16 | Backlight source control circuit and liquid crystal display device |
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| CN201811366972.7A CN109272946B (en) | 2018-11-16 | 2018-11-16 | Backlight source control circuit and liquid crystal display device |
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| CN109272946B (en) | 2020-06-05 |
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Address after: 215301, 1, Longteng Road, Kunshan, Jiangsu, Suzhou Applicant after: Kunshan Longteng Au Optronics Co Address before: 215301, 1, Longteng Road, Kunshan, Jiangsu, Suzhou Applicant before: Kunshan Longteng Optronics Co., Ltd. |
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