[summary of the invention]
It is an object of the invention to provide a kind of backlight drive circuit, to solve the life of the backlight drive circuit of prior artProduce relatively costly technical problem.
For solving above-mentioned technical problem, the present invention provides a kind of backlight drive circuit, comprising:
Input block, boost module, output module, the first detector unit and current adjustment unit；Described input block,Described boost module and described output module are sequentially connected with, and described output module is connected with the first end of load, described boostingModule, described first detector unit, described current adjustment unit are commonly connected to the second end of described load；
Described boost module, for generating the first control signal, and increases described input according to described first control signalThe voltage of unit input, obtains driving voltage；So that described driving voltage is corresponding with display pattern；Wherein said display pattern bagInclude two dimensional mode and three-dimensional display mode；
Described first detector unit, for detecting electric current input described load, and according to described electric current adjustment described theThe dutycycle of one control signal, so that the electric current inputting described load remains constant；
Described current adjustment unit, for adjusting the electric current inputting described load according to the second external control signal.
In the backlight drive circuit of the present invention, described current adjustment unit includes the first resistance and the first switch element,One end of described first resistance is connected with the second end of described load, the other end of described first resistance and described first switch unitThe input of part connects, and the control end of described first switch element is connected with described second control signal, described first switch unitThe output head grounding of part.
In the backlight drive circuit of the present invention, described boost module includes that boosting unit, described boosting unit include controlDevice processed, inductance and second switch element；
Described controller has the first outfan, the first test side；Described first outfan is used for exporting described first controlSignal processed；Common node between described first test side with described first resistance and described load is connected；
One end of described inductance is connected with described input module, the other end of described inductance and described second switch elementInput connects, and the control end of described second switch element is connected with described first outfan, described second switch element defeatedGo out to hold ground connection.
In the backlight drive circuit of the present invention, described boost module also includes the second detector unit, described second detectionUnit, for detecting the size of described driving voltage, when described driving voltage is more than preset value, controls described boosting unit and stopsOnly work.
In the backlight drive circuit of the present invention, described controller also has the second test side, described second detector unitIncluding the 3rd resistance, one end of described 3rd resistance is examined with the outfan of described second switch element and described second respectivelySurvey end connects, the other end ground connection of described 3rd resistance.
In the backlight drive circuit of the present invention, described first detector unit includes the second resistance, described second resistanceOne end is connected with described first test side, the other end ground connection of described second resistance.
In the backlight drive circuit of the present invention, described output module includes rectification unit, the input of described rectification unitEnd is connected with the input of described second switch element, and the outfan of described rectification unit connects described load.
In the backlight drive circuit of the present invention, described output module also includes filter capacitor, the one of described filter capacitorEnd is connected with the outfan of described rectification unit, the other end ground connection of described filter capacitor.
In the backlight drive circuit of the present invention, described backlight drive circuit also includes the 3rd switch element, the described 3rdThe input of switch element is connected with the second end of described load, and the end that controls of described 3rd switch element is controlled with the external the 3rdSignal processed connects, and the outfan of described 3rd switch element is connected with described common node.
In the backlight drive circuit of the present invention, described input block includes total input and storage electric capacity, described storageOne end of electric capacity is connected with described total input, the other end ground connection of described storage electric capacity.
The backlight drive circuit of the present invention, owing to redesigning existing backlight drive circuit, simplifies existingCircuit, thus decrease the quantity of chip, reduce production cost.
[detailed description of the invention]
The explanation of following embodiment is particular implementation that is graphic with reference to add, that implement in order to illustrate the present invention may be used toExample.The direction term that the present invention is previously mentioned, such as " on ", D score, "front", "rear", "left", "right", " interior ", " outward ", " side "Deng, it is only the direction with reference to annexed drawings.Therefore, the direction term of use is to illustrate and understand the present invention, and is not used toLimit the present invention.In the drawings, the unit that structure is similar is to represent with identical label.
Refer to the structural representation that Fig. 1, Fig. 1 are existing backlight drive circuit.
Existing backlight drive circuit include boost chip 100 (such as BOOST IC), micro-control unit 101 (MCU),Controller 102 (LED controler)；This backlight drive circuit has total input 11, at the beginning of this total input 11 is used for inputtingBeginning voltage；This backlight drive circuit also includes storing electric capacity C1 and filter capacitor C2, and commutator D1.
Wherein micro-control unit 101 includes the first outfan 15 and the second outfan 16, this first outfan 15 forBoost chip 100 provides and enables signal, works triggering boost chip 100；This second outfan 16, for showing mould by correspondenceThe data transmission such as electric current required under formula and dutycycle are to controller 102, and controller 102 is further according to the data genaration electricity of inputPressure control signal.Controller 102 has the 3rd outfan 14 and the first test side 18, and this first test side 18 is used for detecting inputVoltage on the voltage of light emitting diode, namely resistance R2, the 3rd outfan 14 is used for transmitting this voltage control signal.
Boost chip 100 has the 4th outfan 12 and the second test side 13, and the 4th outfan 12 is used for exporting boostingControl signal, voltage control signal is for adjusting the dutycycle of voltage up control signal；This second test side 13 is used for detecting processVoltage on voltage swing after boosting, namely resistance R1.
When specific works, micro-control unit 101 triggers boost chip 100 and works, and boost chip 100 is according to control afterwardsThe voltage control signal that device 102 provides controls switch and the Guan Bi of the first field-effect transistor Q1, to control the charge and discharge of inductance LThe electricity time, thus improve the size of initial voltage.This outer controller 102 also detects the size of current of input light emitting diode,When electric current is more than preset value, voltage control signal is carried out feedback control, so that input current keeps constant.Boost chip100 voltage swings that also detection inductance L1 exports, when voltage is more than preset value, controls the first field-effect transistor Q1 and disconnect,No longer promote initial voltage.
When display pattern is 3D flash pattern, controller, by the control signal of the 5th input 17 output, controls theThe opening and closing of two field-effect transistor Q2, and then make LED flash.
Refer to the structural representation of the backlight drive circuit that Fig. 2, Fig. 2 are the present invention.
The backlight drive circuit of the present invention, as in figure 2 it is shown, include: input block 201, boost module 202, output module203, the first detector unit 204 and current adjustment unit 205；Described input block 201, described boost module 202 and instituteStating output module 203 to be sequentially connected with, described output module 203 is connected with first end (such as positive pole) of load 30, and this load isThe light emitting diode of at least two series connection, described boost module 202, described first detector unit 204, described electric current adjust singleUnit 205 is commonly connected to second end (such as negative pole) of described load 30；Described input block 201 is used for providing voltage source.
Described boost module 202 is used for generating the first control signal (namely input Q1 controls voltage of end), and according to instituteState the first control signal and increase the voltage of described input block 201 input, obtain driving voltage (namely voltage of inductance output)；So that described driving voltage is corresponding with display pattern；Wherein said display pattern includes two dimensional mode and three dimensional display mouldFormula；
Described first detector unit 204, for detecting the electric current inputting described load 30, and adjusts institute according to described electric currentState the dutycycle of the first control signal, so that the electric current inputting described load remains constant；Specifically, the first detector unit 204By the voltage on detection resistance R2, obtain exporting the electric current of described load, and calculated electric current is entered with predetermined threshold valueRow compares, if being not equal to predetermined threshold value, is then adjusted the dutycycle of the first control signal, by adjusting the first control letterNumber dutycycle, namely the voltage of input load is carried out feedback control, so that the electric current inputting described load 30 keepsConstant.
Described current adjustment unit 205, for adjusting the electricity inputting described load according to the second external control signal P2Stream.Described current adjusting module 205, may be used for adjusting, according to the second external control signal, the electricity being connected with described load 30The resistance of resistance, to adjust the electric current inputting described load.Described second control signal P2 is such as square-wave signal, this second controlSignal P2 is such as according to display schema creation.When in two dimensional mode, the second control signal P2 is low level, when in three-dimensionalDuring display pattern, the second control signal P2 is high level.
Described current adjustment unit 205 includes the first resistance R3 and the first switch element Q3, the one of described first resistance R3End is connected with second end (negative pole) of described load 30, and the other end of described first resistance R3 is with described first switch element Q3'sInput connects, and the control end of described first switch element Q3 is connected with described second control signal P2, described first switch unitThe output head grounding of part Q3.This first switch element Q3 is such as field-effect transistor.
Described boost module 202 includes boosting unit, and it includes controller 20, inductance L1 and second switch element Q1,This second switch element Q1 is such as field-effect transistor.
Described controller 20 has first outfan the 21, first test side 22；Described first outfan 21 is used for exporting instituteState the first control signal；Common node N between described first test side 22 and described first resistance R3 and described load 30 is evenConnect；
One end of described inductance L1 is connected with described input module 201, and the other end of described inductance L1 is opened with described secondThe input closing element Q1 connects, and the control end of described second switch element Q1 is connected with described first outfan 21, and described theThe output head grounding of two switch element Q1.
Described boost module 202 also includes that the second detector unit 24, described second detector unit 24 are driven described in being used for detectingThe size of galvanic electricity pressure, when described driving voltage is more than preset value, controls described boosting unit and quits work.Specifically, controlDevice 20 also detects the voltage swing of inductance L1 output, when output voltage size is more than preset value so that boosting unit stops workMake, namely Q1 is disconnected.
Described controller 20 also has the second test side 23, and described second detector unit 24 includes the 3rd resistance R1, describedOne end of 3rd resistance R1 is connected with the outfan of described second switch element Q1 and described second test side 23 respectively, instituteState the other end ground connection of the 3rd resistance R1.
Described first detector unit 204 includes the second resistance R2, one end of described second resistance R2 and described first detectionEnd 22 connection, the other end ground connection of described second resistance R2.It is understood that one end of the second resistance R2 the most respectively with resistanceOne end of R3, the outfan of Q2 connect.
Described output module 203 includes rectification unit D1, the input of described rectification unit D1 and described second switch unitThe input of part Q1 connects, and the outfan of described rectification unit D1 connects described load 30.
Described output module 203 also includes filter capacitor C2, one end of described filter capacitor C2 and described rectification unit 203Outfan connect, the other end ground connection of described filter capacitor C2.
Described backlight drive circuit also includes the 3rd switch element Q2, and the input of described 3rd switch element Q2 is with describedSecond end of load 30 connects, and the end that controls of described 3rd switch element Q2 is connected with the 3rd external control signal P3, describedThe outfan of the 3rd switch element Q2 is connected with described common node N.Namely the 3rd control signal P3 be square-wave signal, work as displayWhen pattern is three-dimensional flash pattern, controlled the closed and disconnected of the 3rd switch element Q2 by the 3rd control signal P3.When the 3rdDuring switch element Q2 Guan Bi, lumination of light emitting diode.When the 3rd switch element Q2 disconnects, light emitting diode is the most luminous, namelyAchieve flicker.
Described input block 201 includes total input 25 and storage electric capacity C1, and one end of described storage electric capacity C1 is with describedTotal input 25 connects, the other end ground connection of described storage electric capacity C1.
Specifically, owing to when three-dimensional display mode, needing to input bigger electric current to load.Therefore at three dimensional display mouldDuring formula, control Q3 by outer signal and close, so that R3 with R2 is in parallel, thus reduce the electricity being connected with light emitting diodeThe resistance of resistance, and then increase the current value of input light emitting diode.Due to the drive circuit after improving, it is not necessary to arrangeMore chip, thus decrease the quantity of chip, therefore reduce production cost.
The backlight drive circuit of the present invention, owing to redesigning existing backlight drive circuit, simplifies existingCircuit, thus decrease the quantity of chip, reduce production cost.
In sum, although the present invention is disclosed above with preferred embodiment, but above preferred embodiment and be not used to limitThe present invention processed, those of ordinary skill in the art, without departing from the spirit and scope of the present invention, all can make various change and profitDecorations, therefore protection scope of the present invention defines in the range of standard with claim.