CN107276421A - Backlight drive circuit - Google Patents
Backlight drive circuit Download PDFInfo
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- CN107276421A CN107276421A CN201710651630.9A CN201710651630A CN107276421A CN 107276421 A CN107276421 A CN 107276421A CN 201710651630 A CN201710651630 A CN 201710651630A CN 107276421 A CN107276421 A CN 107276421A
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/30—Driver circuits
- H05B45/37—Converter circuits
- H05B45/3725—Switched mode power supply [SMPS]
- H05B45/385—Switched mode power supply [SMPS] using flyback topology
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M5/00—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases
- H02M5/02—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc
- H02M5/04—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc by static converters
- H02M5/10—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc by static converters using transformers
- H02M5/12—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc by static converters using transformers for conversion of voltage or current amplitude only
-
- 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
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
- H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
- H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
- H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
- H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
- H02M3/33576—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements having at least one active switching element at the secondary side of an isolation transformer
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/30—Driver circuits
- H05B45/395—Linear regulators
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/0067—Converter structures employing plural converter units, other than for parallel operation of the units on a single load
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Circuit Arrangement For Electric Light Sources In General (AREA)
Abstract
The invention discloses a kind of backlight drive circuit, including：Input block；Transformer, it includes：First armature winding, it is electrically connected with the output end of the input block；First secondary windings, it is coupled with first armature winding；First assists winding, itself and first level winding coupled；Voltage output unit；Control driver element；Wherein, the transformer also includes the second assists winding unit, the second assists winding unit and first level winding coupled, the second assists winding unit is electrically connected with the control driver element, the output voltage of first assists winding is less than the output voltage of the second assists winding unit, and first assists winding is commonly connected to the voltage controling end of the control driver element with the second assists winding unit.Using the present invention, there is the output voltage range for the voltage output unit that can expand backlight drive circuit.
Description
Technical field
The present invention relates to display technology field, more particularly to a kind of backlight drive circuit.
Background technology
With the continuous progress of technology, the backlight technology of liquid crystal display device is continuously available development.Traditional liquid crystal display
The backlight of device uses cold-cathode fluorescence lamp (FL).But it is due to that FL backlights have that color restoration capability is poor, luminous effect
Rate is low, flash-over characteristic is poor under discharge voltage high and low temperature, heating reaches the shortcomings of stable gray scale time is long, has currently developed
Use the back light source technique of LED backlight.
, it is necessary to provide the driving of its normal luminous by special backlight drive circuit for LED strip in LED backlight
Voltage.Existing backlight drive circuit refers to Fig. 1, it include input block 110, transformer T ', voltage output unit 120,
Driver element 130, constant current driving unit 140 are controlled, wherein, the input block 110 is used for the access of power supply, the transformer
T ' is electrically connected with the input block 110, and the output end of the transformer T ' drives with voltage output unit 120, control respectively
Unit 130 is electrically connected, and the voltage output unit 120 is used to provide driving voltage, institute to backlight and constant-current control unit 140
Stating control driver element 130 is used for the output of control voltage output unit 120, and the constant current driving unit 140 is used to control institute
State the current range flowed through on backlight.
Wherein, the transformer T ' includes armature winding P ', secondary windings S1 ' and assists winding S2 ', the secondary windings
S1 ' couples the armature winding P ', and the assists winding S2 ' couples the secondary windings S1 ', in the present embodiment, described first
Level winding P ' coil turn/secondary windings S1 ' coil turn is 1/1, the coil turn of the secondary windings S1 '/described
Assists winding S2 ' coil turn is 3/1, namely the coil turn of the secondary windings S1 ' is more than the assists winding S2's '
Coil turn, so that, when secondary windings S1 ' output voltage is 30V, assists winding S2 ' output voltage is 10V.Typically
In fact, the existing control driver element 130 is general can control in design to secondary windings S1 ' output voltage range
System, the output voltage range for for example controlling assists winding S2 ' is 9V-12V, controls driver element 130 then to control when less than 9V
Backlight drive circuit is closed, the no longer output voltage of voltage output unit 120 of backlight drive circuit, so that secondary windings S1 '
Output voltage range is 27V-36V.However, due to the requirement of different product, backlight typically also can be different, cause backlight institute
The voltage needed also can be different, such as the backlight required voltage more than LED is larger, the few backlight required voltage of LED
It is smaller, so that, when secondary windings S1 ' output voltage is less than 27V, now assists winding S2 ' output voltage is less than 9V, no
In 9V-12V voltage range, now control the control backlight drive circuit of driver element 130 not work, cause such a backlight to be driven
The secondary windings S1 ' of dynamic circuit output voltage range is narrower, so that the output voltage range of voltage output unit 120 compares
It is narrow, be not suitable for the larger product of voltage differences or the larger product of voltage pulsation shares this kind of backlight drive circuit, so as to limit
The use of this kind of backlight drive circuit is made.
The content of the invention
The technical problems to be solved by the invention are that there is provided a kind of backlight drive circuit.Backlight drive circuit can be expanded
Voltage output unit output voltage range.
In order to solve the above-mentioned technical problem, the invention provides a kind of backlight drive circuit, including：
Input block, it is used for the access of power supply；
Transformer, it includes：
First armature winding, it is electrically connected with the output end of the input block；
First secondary windings, it is coupled with first armature winding；
First assists winding, itself and first level winding coupled；
Voltage output unit, it is electrically connected with the output end of first secondary windings, and it is used to export backlight drive electricity
Pressure；
Driver element is controlled, it is electrically connected with first assists winding；
Wherein, the transformer also includes the second assists winding unit, the second assists winding unit and described first
Secondary windings is coupled, and the second assists winding unit is electrically connected with the control driver element, first assists winding
Output voltage be less than the second assists winding unit output voltage, and first assists winding with described second auxiliary around
Group unit is commonly connected to the voltage controling end of the control driver element.
In an embodiment of the present invention, the second assists winding unit includes：
Second auxiliary primary winding, itself and first level winding coupled；
Second auxiliary secondary winding, itself and the second auxiliary primary winding coupled, the second auxiliary secondary winding with
The voltage controling end electrical connection of the control driver element.
In an embodiment of the present invention, the output voltage of the second auxiliary secondary winding is more than first assists winding
Output voltage.
In an embodiment of the present invention, the coil turn of the second auxiliary primary winding is more than first secondary windings
Coil turn.
In an embodiment of the present invention, the coil of the coil turn of first secondary windings/first assists winding
The number of turn is more than the coil turn of coil turn/the second auxiliary secondary winding of the second auxiliary primary winding.
In an embodiment of the present invention, the backlight drive circuit also includes constant current driving unit, and the constant current driving is single
Output end, the voltage output unit of member respectively with the second auxiliary primary winding are electrically connected.
In an embodiment of the present invention, in addition to reduction voltage circuit, described reduction voltage circuit one end and second auxiliary primary
The output end electrical connection of winding, the reduction voltage circuit other end electrically connects with constant current driving unit, second auxiliary primary around
The voltage of group output is exported to constant current driving unit after being depressured via reduction voltage circuit.
In an embodiment of the present invention, the voltage output unit and the reduction voltage circuit are commonly connected to constant current driving list
The voltage input end of member, the reduction voltage circuit is exported is more than the voltage output to the voltage of constant current driving unit voltage input end
Unit exports the voltage to constant current driving unit voltage input end.
In an embodiment of the present invention, the reduction voltage circuit includes the second triode, the 35th resistance and the pole of voltage stabilizing two
Pipe, the colelctor electrode of second triode electrically connects the output end of the second auxiliary primary winding, second triode
The 35th resistance is electrically connected between colelctor electrode and base stage, the base stage of second triode electrically connects the moon of voltage-regulator diode
Pole, the plus earth of the voltage-regulator diode, the emitter stage electrical connection constant current driving unit of second triode.
In an embodiment of the present invention, in addition to the 15th diode, the 17th diode and electric capacity, the described 15th
The anode of pole pipe electrically connects the first end of the second auxiliary primary winding, and the electric capacity is connected electrically in the 15th diode
Anode and the second auxiliary primary winding the second end between, the anode of the 17th diode electrically connects the two or three pole
The emitter stage of pipe, the negative electrode electrical connection constant current driving unit of the 17th diode.
Implement the present invention, have the advantages that：
Because the transformer also includes the second assists winding unit, the second assists winding unit and first level around
Group coupling, the second assists winding unit is electrically connected with control driver element, and the output voltage of first assists winding is small
In the output voltage of the second assists winding unit, and first assists winding and the second assists winding unit are common
It is connected to the voltage controling end of control driver element；The voltage controling end of driver element is controlled to receive the second assists winding unit
Output voltage, the lower limit of the output voltage of the first secondary coil can be widened, so that the output voltage of voltage output unit
The lower limit of scope can be widened, and can be applicable the demand of different backlights, improve the application model of backlight drive circuit
Enclose.
Brief description of the drawings
, below will be to embodiment or prior art in order to illustrate more clearly of technical scheme of the invention or of the prior art
The accompanying drawing used required in description is briefly described, it should be apparent that, drawings in the following description are only the present invention's
Some embodiments, for those of ordinary skill in the art, on the premise of not paying creative work, can also be according to this
A little accompanying drawings obtain other accompanying drawings.
Fig. 1 is a kind of circuit diagram of backlight drive circuit of prior art；
Fig. 2 is the circuit diagram of one embodiment of the invention backlight drive circuit；
Shown by reference numeral：
110th, 210- input blocks；120th, 220- voltage output units；211-LC wave filters；212-RCD absorbing circuits；
213- bridge rectifiers；130th, 230- controls driver element；140th, 240- constant current driving units；250- reduction voltage circuits；R1-
R35- resistance；C1-C17- electric capacity；D1-D17- diodes；T ', T- transformers；Q1, Q2- triode；Q3-MOS is managed；U- optocouplers；
L- inductance；The operational amplifiers of OP1- first；The operational amplifiers of OP2- second.
Embodiment
Below in conjunction with the accompanying drawing in the present invention, the technical scheme in the present invention is clearly and completely described, shown
So, described embodiment is only a part of embodiment of the invention, rather than whole embodiments.Based on the reality in the present invention
Example is applied, the every other embodiment that those of ordinary skill in the art are obtained under the premise of creative work is not made all belongs to
In the scope of protection of the invention.
The term " comprising " and " having " occurred in present specification, claims and accompanying drawing and their any changes
Shape, it is intended that covering is non-exclusive to be included.For example contain the process of series of steps or unit, method, system, product or
The step of equipment is not limited to list or unit, but alternatively also include the step of do not list or unit, or it is optional
Ground is also included for the intrinsic other steps of these processes, method, product or equipment or unit.In addition, term " first ", " the
Two " and " the 3rd " etc. be, for distinguishing different objects, and to be not intended to describe specific order.
The present invention provides a kind of backlight drive circuit, refers to Fig. 2, including input block 210, transformer T, voltage output
Unit 220 and control driver element 230.
The input block 210 is used for the access of power supply, and the input block 210 can connect the power supply electricity of display device
Road, the voltage that can also directly connect on power supply, power supply is input in backlight drive circuit by input block 210.In this implementation
In example, the input block 210 includes current rectifying and wave filtering circuit and RCD absorbing circuits 212, and the current rectifying and wave filtering circuit is used for power supply
Access, the current rectifying and wave filtering circuit include bridge rectifier 213 and LC wave filters 211, particularly, the bridge rectifier
Circuit 213 is formed by connecting by diode D1-D4, two inputs for connecting the input block 210, the LC wave filters
211 electrically connect with two output ends of bridge rectifier 213, and the LC wave filters 211 include inductance L and the first electric capacity C1,
The inductance L is electrically connected with the first output end of bridge rectifier 213, and the two ends of the first electric capacity C1 are defeated with inductance L's
The second output end for going out end and bridge rectifier 213 is electrically connected, and the of the first electric capacity C1 and bridge rectifier 213
One end electrical ground of two output ends electrical connection；The RCD absorbing circuits 212 are electrically connected with the output end of current rectifying and wave filtering circuit,
Specifically the output end with the LC wave filters 211 is electrically connected, and the RCD absorbing circuits 212 are used to filter on input block 210
Sharp wave voltage, the RCD absorbing circuits 212 include the 6th resistance R6, the second electric capacity C2, the 3rd electric capacity C3, the 4th electric capacity C4 and
5th diode D5, wherein, the 6th resistance R6, the output of the second electric capacity C2 and the 4th electric capacity C4 with LC wave filters 211
End electrical connection, and the 6th resistance R6, the second electric capacity C2 and the common one end of the 4th electric capacity C4 form the of RCD absorbing circuits 212
One output end, the negative electrode of the 5th diode D5 is connected with the 6th resistance R6, the 3rd electric capacity C3 and the second electric capacity C2 string
Join, and the circuit between the circuit and the 6th resistance R6 and the 5th diode D5 between the 3rd electric capacity C3 and the second electric capacity C2 passes through
Wire is electrically connected, and the non-one end being connected with the second electric capacity C2 of the 3rd electric capacity C3 and the 5th diode D5 anode pass through wire
It is electrically connected to form the second output end of RCD absorbing circuits 212, the output ends of the 4th electric capacity C4 not with LC wave filters 211
One end electrical ground of electrical connection.
The transformer T is electrically connected with input block 210, particularly, the transformer T and RCD absorbing circuits 212
Output end is electrically connected, and the transformer T includes the first armature winding P, the first secondary windings S1, the first assists winding S2.Wherein,
The electrical connection corresponding with the first output end, the second output end of RCD absorbing circuits 212 of the two ends of the first armature winding P, it is described
First secondary windings S1 is coupled with the first armature winding P, in the present embodiment, the coil turn of the first secondary windings S1
The/the first armature winding P of number coil turn is 1/1, and the first assists winding S2 is coupled with the first secondary windings S1,
In the present embodiment, the first secondary windings S1 coil turn/first assists winding S2 coil turn is 3/1, Ye Ji
One secondary windings S1 coil turn is more than the first assists winding S2 coil turn.For example, when defeated on the first armature winding P
When going out voltage for 30V, the output voltage on the first secondary windings S1 is also that the output voltage on 30V, the first assists winding S2 is
10V.In the present embodiment, the transformer T also includes iron core, the first armature winding P, the first secondary windings S1, first
Assists winding S2 is wound on iron core.
The voltage output unit 220 is electrically connected with the first secondary windings S1 two output ends, the voltage output unit
220 are used for output voltage to backlight, namely provide power to the emitting components such as LED in backlight.In the present embodiment
In, the voltage output unit 220 includes commutation diode D6, the 5th electric capacity C5, the 6th electric capacity C6, the 7th resistance R7, the 8th
Resistance R8 and two output voltage terminals, particularly, the first of the anode of the commutation diode D6 and the first secondary windings S1
Output end is electrically connected, the two ends of the 5th electric capacity C5 negative electrode respectively with commutation diode D6, the of the first secondary windings S1
Two output ends are electrically connected, the second output end electrical ground of the first secondary windings S1, the 8th resistance R8 and described the
One secondary windings S1 the second output end electrical connection, the 7th resistance is in parallel with the 8th resistance R8, the 6th electric capacity C6's
One end is electrically connected with commutation diode D6 negative electrode, the earth-free one end electricity of the other end and the 8th resistance of the 6th electric capacity C6
Connection, the two ends of the 6th electric capacity C6 are electrically connected with two output voltage terminals respectively；In the present embodiment, the pole of rectification two
Pipe D6 is used to carry out rectification to the voltage that the first secondary windings S1 is exported, and the 5th electric capacity C5, the 6th electric capacity C6 are to for the first time
The voltage of level winding S1 outputs carries out voltage stabilizing and filtering, and the output voltage terminals are used to power to backlight.
The control driver element 230 is electrically connected with the first assists winding S2, the control control voltage of driver element 230
The voltage output of output unit 220.In the present embodiment, the control driver element 230 is also electrically connected with input block 210,
Specifically electrically connected with the output end of bridge rectifier.
In order that the output voltage range of voltage output unit 220 is relatively wide, by increasing output voltage in the present embodiment
Lower limit widen output voltage range, particularly, in the present embodiment, the transformer T also includes the second assists winding
Unit, the second assists winding unit is coupled with the first secondary windings S1, and the second assists winding unit drives with control
Moving cell 230 is electrically connected, and the output voltage of the first assists winding S2 is less than the output electricity of the second assists winding unit
Pressure, and the first assists winding S2 is commonly connected to control the voltage of driver element 230 with the second assists winding unit
Control end.So as to, when the first assists winding S2 output voltage and the second assists winding unit voltage common transport to control
During the voltage controling end of driver element 230, because the output voltage of the second assists winding unit is greater than the first assists winding S2
Output voltage so that control driver element 230 voltage controling end receive the second assists winding unit output voltage so that
The lower limit of the output voltage of first secondary coil can be widened, so that the output voltage range of voltage output unit 220
Lower limit can be widened, so as to be applicable the demand of different backlights, so as to improve the application of backlight drive circuit
Scope.
Citing is got on very well, when control the voltage controling end of driver element 230 voltage range be 9-12V when, when first auxiliary around
When group S2 output voltage is less than 9V, it is assumed that be 8V, now, the output voltage of the second assists winding unit is greater than first
Assists winding S2 output voltage, for example, 9.1V, now, because the output voltage 9.1V of the second assists winding unit is more than the
One assists winding S2 output voltage 8V, so that when the voltage controling end of control driver element 230 receives 9.1V's and 8V simultaneously
During voltage, the voltage controling end of control driver element 230 can recognize 9.1V voltage, now scope of the voltage range in 9V-12V
It is interior, so that control driver element 230 backlight drive circuit will not be controlled to close, now, the first secondary windings S1 output voltage
24V can be reached, so that, the output voltage of the first secondary windings S1 compared with prior art cannot be below 27V, widen first
Secondary windings S1 output voltage range, hereafter, the first secondary windings S1 output voltage are handled by voltage output unit 220
Exported afterwards, equally, the output voltage range of voltage output unit 220 is widened, so as to be applicable the different back ofs the body
The demand of light source, so as to improve the application of backlight drive circuit.
In the present embodiment, the second assists winding unit includes the second auxiliary primary winding S4 and the second auxiliary secondary
Winding S3, the second auxiliary primary winding S4 are coupled with the first secondary windings S1, the second auxiliary secondary winding S3
Coupled with the second auxiliary primary winding S4, the second auxiliary secondary winding S3 and the control driver element 230 electricity
Control end electrical connection, namely the second auxiliary secondary winding S3 and the first assists winding S2 is pressed to be commonly connected to control driver element
230 voltage controling end.In the present embodiment, after the first secondary windings S1 output voltage is determined, second auxiliary time
Output voltage on level winding S3 is more than the output voltage of the first assists winding S2.
In order to realize that the output voltage on the second auxiliary secondary winding S3 is more than the defeated of the first assists winding S2
Go out voltage, in the present embodiment, the coil turn of the second auxiliary primary winding S4 is more than the first secondary windings S1's
Coil turn, for example, the coil turn of the second auxiliary primary winding S4/first secondary windings S1 coil turn scope
For 2:1-4:1, for example, 2:1、3:1、4:1, below with 3:Illustrated exemplified by 1.In the present embodiment, first level around
The group S1 assists winding S2 of coil turn/first coil turn ＞ the second auxiliary primary windings S4 coil turn/the second is auxiliary
Help secondary windings S3 coil turn, that is, the first assists winding S2 coil turn/first secondary windings S1 coil turn
The auxiliary primary winding S4 of ＜ the second auxiliary secondary windings S3 coil turn/second coil turn, due to the described second auxiliary
Armature winding S4 coil turn is more than the coil turn of the first secondary windings S1, so that, state the second auxiliary secondary winding
Output voltage on S3 is more than the output voltage of the first assists winding S2.
For example, the coil turn of the secondary windings S1 of coil turn/first as the second auxiliary primary winding S4
For 3:1, the first secondary windings S1 coil turn/first assists winding S2 coil turn are 3:When 1, namely second auxiliary
The auxiliary primary winding S4 of secondary windings S3 coil turn/second coil turn is helped to be greater than 1:3, such as the second auxiliary secondary
The auxiliary primary winding S4 of winding S3 coil turn/second coil turn is 1:1, so that, the first secondary windings S1 coil
The auxiliary secondary winding S3 of the number of turn/second coil turn is 1:3, so that, when the first secondary windings S1 output voltage is 3V,
Now, the output voltage of the first assists winding S2 is 1V, and the second auxiliary secondary winding S3 output voltage is 9V, so as to work as
The voltage controling end of driver element 230 is controlled while when receiving 9V and 1V voltage, controlling the voltage controling end of driver element 230
9V voltage can be recognized, now voltage range is in the range of 9V-12V, so as to control driver element 230 backlight will not be controlled to drive
Dynamic circuit is closed, and now, the first secondary windings S1 output voltage can reach 3V, so that the first secondary windings S1 output electricity
Pressure scope can reach 3V-36V scope, so as to expand the output voltage range of voltage output unit 220, can be applicable not
The need for backlight drive circuit.
In the present embodiment, the backlight drive circuit also includes constant current driving unit 240, the constant current driving unit
240 voltage input end is electrically connected with voltage output unit 220, and the constant current driving unit 240 is used to control on backlight
Current range, the output voltage of voltage output unit 220 is used to work for constant current driving unit 240.In the present embodiment, by
It can be reduced in the lower limit of the first secondary windings S1 output voltage, so as to cause voltage output unit 220 to export to perseverance
The voltage of stream driver element 240 is also reduced, so as to cause constant current driving unit 240 not work.In order to improve this
Problem, in the present embodiment, the output of the voltage input end of the constant current driving unit 240 also with the second auxiliary primary winding S4
End electrical connection, the output voltage of the second auxiliary primary winding S4 is used to be supplied to constant current driving unit 240, in the present embodiment
In, the output voltage on the second auxiliary primary winding S4 is more than the output voltage on the first secondary windings S1.
Constant current driving unit 240 is damaged in order to prevent the overtension of the second auxiliary primary winding S4 outputs, in this reality
Apply in example, the backlight drive circuit also include reduction voltage circuit 250, the reduction voltage circuit 250 be used for the second auxiliary primary around
Group S4 output voltage is depressured, and described one end of reduction voltage circuit 250 is electrically connected with the second auxiliary primary winding S4 output end,
The other end of reduction voltage circuit 250 is electrically connected with the voltage input end of constant current driving unit 240, the second auxiliary primary winding
S4 output voltage via reduction voltage circuit 250 be depressured after export to constant current driving unit 240, the reduction voltage circuit 250 export to
The voltage of the voltage input end of constant current driving unit 240 exports defeated to the voltage of constant current driving unit 240 more than voltage output unit 220
Enter the voltage at end, so as to prevent constant current driving unit 240 too low without work due to the output voltage of voltage output unit 220
Make.
Particularly, in the present embodiment, the reduction voltage circuit 250 includes the second triode Q2, resistance R35 and voltage stabilizing two
Pole pipe D16, the second triode Q2 colelctor electrode electrically connect the second auxiliary primary winding S4 output end, the two or three pole
Electric connection resistance R35 between pipe Q2 colelctor electrode and base stage, the second triode Q2 base stage electrical connection voltage-regulator diode D16
Negative electrode, the plus earth of the voltage-regulator diode D16, the second triode Q2 emitter stage electrical connection constant current driving unit
240.In the present embodiment, because voltage-regulator diode D16 has carried out pressure limiting to the second triode Q2 base stage, for example, second is limited
The voltage of triode Q2 base stage is 11V, so that the output voltage of the second triode Q2 emitter stages is limited, so as to
Prevent the second triode Q2 emitter stages are exported from damaging constant current driving unit 240 to the overtension of constant current driving unit 240.Separately
Outside, in the present embodiment, it is additionally provided with the 17th diode between the reduction voltage circuit 250 and the constant current driving unit 240
D17, the 17th diode D17 anode electrically connect the second triode Q2 emitter stage, the 17th diode D17's
Negative electrode electrically connects the constant current driving unit 240, and the 17th diode D17 is used for rectified action.In the present embodiment, institute
The second triode Q2 is stated for the triode of npn second.
In the present embodiment, the backlight drive circuit also includes the 15th diode D15 and the 17th electric capacity C17, institute
State output ends and reduction voltage circuit of the 15th diode D15 and the 17th electric capacity C17 positioned at the second auxiliary primary winding S4
Between 250 input, particularly, the anode of the 15th diode D15 is with the second auxiliary primary winding S4's
First output end is electrically connected, the second output end electrical ground of the second auxiliary primary winding S4, the 17th electric capacity C17
Two ends electrically connected respectively with the 15th diode D15 negative electrode and the second output end of the second auxiliary primary winding S4,
And the negative electrode and the second triode Q2 colelctor electrode of the 15th diode D15, the 15th diode D15 is used for the
Two auxiliary primary winding S4 output voltage carries out rectification, and the 17th electric capacity C17 is used for the second auxiliary primary winding S4
Output voltage carry out voltage stabilizing and filtering.
In addition, in the present embodiment, the constant current driving unit 240 includes the first operational amplifier OP1 and the second computing
Amplifier OP2.The backlight drive circuit also includes optocoupler U, the optocoupler U photophores and the electricity of constant current driving unit 240
Connection, the first end of the light-receiving device of the optocoupler U passes through the 13rd resistance R13, the 9th resistance R9 and the control driver element
230 are electrically connected, and the output end of the 13rd resistance is electrically connected with a port of the control driver element 230, described
9th resistance R9 output end is electrically connected with another port of the control driver element 230, moreover, the 9th resistance R9
Series arm with the 7th electric capacity C5, the tenth resistance R10 formation is in parallel, and the output end of the 13rd resistance R13 is also via the
11 resistance R11 are electrically connected with the second end of the light-receiving device of the optocoupler U, and the second end of the light-receiving device of the optocoupler U passes through
21 resistance R21 electrical grounds.
In addition, in the present embodiment, the backlight drive circuit also includes the resistance R5 of first resistor R1- the 5th, the 12nd
Resistance R12, the resistance R20 of the 14th resistance R14- the 20th, the resistance R34s of the 22nd resistance R22- the 34th, the 8th electric capacity
The components such as the electric capacity C16 of C8- the 16th, the diode D15 of the 7th diode D7- the 15th, the first triode Q1, metal-oxide-semiconductor Q3, tool
Body annexation is as follows, and continuing with referring to Fig. 2, the first output end of the bridge rectifier 213 is via first resistor R1,
Two resistance R2, the 12nd resistance R12 electrical grounds, wherein the output end of the second resistance is electrically connected with control driver element 230
Connect, the 12nd resistance R12 is in parallel with the 8th electric capacity C8；Between the first output end and inductance L of the bridge rectifier 213 also
Provided with 3rd resistor R3, the 4th resistance R4 and the 5th resistance R5, the 3rd resistor R3, the 4th resistance R4 series connection and two ends difference
Electrically connect the first output end of the bridge rectifier 213 and the first triode Q1 base stage, the two of the 5th resistance R5
End is electrically connected the first output end of the bridge rectifier 213 and the first triode Q1 colelctor electrode, wherein described the
One triode Q1 colelctor electrode electrical ground, the emitter stage of the first triode Q1 is electrically connected with control driver element 230.Institute
The second output end electrical connection metal-oxide-semiconductor Q3 of RCD absorbing circuits 212 source electrode is stated, the drain electrode of the metal-oxide-semiconductor Q3 is via the 17th electricity
Hinder R17 electrical grounds, the drain electrode of the metal-oxide-semiconductor Q3 is also via the 14th resistance R14, the 9th electric capacity C9 electrical grounds, wherein the
14 resistance R14 output end is also electrically connected with the port for controlling driver element 230, one end of the 9th electric capacity C9 ground connection and control
The another port electrical connection of driver element 230, moreover, the grid of the metal-oxide-semiconductor Q3 is via the 16th resistance R16 and the MOS
Pipe Q3 drain electrode electrical connection, the grid of the metal-oxide-semiconductor Q3 is electrically connected via the 15th resistance R15 with control driver element 230.Institute
The first assists winding S2 and the second auxiliary secondary winding S3 the second end electrical ground are stated, the first assists winding S2's
First end is electrically connected via the 19th resistance R19, the 9th diode D9, the 8th diode D8 with control driver element 230, described
One end that 8th diode D8 is electrically connected with control driver element 230 is also electrically connected the tenth electric capacity C10, the 11st electric capacity
C11 first end, the tenth electric capacity C10, the 11st electric capacity C11 the second end electrical ground, the 9th diode D9,
Circuit between eight diode D8 is electrically connected to the tenth electric capacity C10, the 11st electric capacity C11 via the 12nd electric capacity C12
Second end；Moreover, the first end of the first assists winding S2 is also via the 20th resistance R20 and the electricity of control driver element 230
Connection, the first end of the second auxiliary secondary winding S3 is electric via the 18th resistance R18 and the 19th resistance R19 output end
Connection.In the present embodiment, the first voltage lead-out terminal in two output voltage terminals of the voltage output unit 220 via
The 32nd resistance R32, the 33rd resistance R33, the electrical ground after the 34th resistance R34 of series connection, moreover, first voltage
Lead-out terminal after the 11st diode D11, the 24th resistance R24, the 12nd diode D12 of series connection also via being electrically connected with
Second voltage lead-out terminal in ground, two output voltage terminals of the voltage output unit 220 is via the 31st of series connection
Electrical ground after resistance R31, the 16th electric capacity C16.Wherein, the negative electrode and the 17th diode of the 11st diode D11
D17 negative electrode electrical connection, the negative electrode of the 11st diode D11 is also via the 25th resistance R25, the 22nd resistance
R22 is electrically connected with the first end of the photophore of the optocoupler U, and output end and the constant current of the 25th resistance R25 drive list
Member 240 is electrically connected, and the 25th resistance R25 output end respectively via the tenth diode D10 in parallel, the 13rd electricity
Hold C13 electrical grounds；Also, the output end of the 24th resistance R24 is electrically connected with the 28th resistance R28, described second
18 resistance R28 output end is electrically connected with the 29th resistance R29, the 30th resistance R30 in parallel, the 29th electricity
R29, the 30th resistance R30 output end electrical ground are hindered, the second end of the photophore of the optocoupler U is respectively via the 13rd
Pole pipe D13 is electrically connected with the first operational amplifier OP1 output end, via the 14th diode D14 and the second operational amplifier
OP2 output end electrical connection, the first end of the photophore of the optocoupler U is via the second of the 23rd resistance R23 and photophore
End electrical connection, moreover, the 33rd resistance R33 output end is electrically connected with the second operational amplifier OP2 reverse input end, the
Two operational amplifier OP2 output end is electrically connected to the second fortune via the 15th electric capacity C15, the 27th resistance R27 of series connection
Calculate amplifier OP2 reverse input end, the output end of the 31st resistance R31 is reverse with the first operational amplifier OP1's
Input is electrically connected, the 14th electric capacity C14, the 26th electricity of the output end of the first operational amplifier OP1 via series connection
The reverse input end that R26 electrically connects the first operational amplifier OP1 is hindered, moreover, the 28th resistance R28 input and the second fortune
Amplifier OP2 input in the same direction electrical connection is calculated, the 28th resistance R28 output end is same with the first operational amplifier OP1's
Electrically connected to input.Furthermore, the electrical ground of constant current driving unit 240.
It should be noted that each embodiment in this specification is described by the way of progressive, each embodiment weight
Point explanation be all between difference with other embodiments, each embodiment identical similar part mutually referring to.
For device embodiment, because it is substantially similar to embodiment of the method, so description is fairly simple, related part referring to
The part explanation of embodiment of the method.
By the description of above-described embodiment, the present invention has advantages below：
Because the transformer also includes the second assists winding unit, the second assists winding unit and first level around
Group coupling, the second assists winding unit is electrically connected with control driver element, and the output voltage of first assists winding is small
In the output voltage of the second assists winding unit, and first assists winding and the second assists winding unit are common
It is connected to the voltage controling end of control driver element.So as to control the voltage controling end of driver element to receive the second assists winding list
The output voltage of member, so that the lower limit of the output voltage of the first secondary coil can be widened, so that voltage output unit
The lower limit of output voltage range can be widened, so as to be applicable the demand of different backlights, so as to improve backlight
The application of drive circuit.
Above disclosure is only preferred embodiment of present invention, can not limit the right model of the present invention with this certainly
Enclose, therefore the equivalent variations made according to the claims in the present invention, still belong to the scope that the present invention is covered.
Claims (10)
1. a kind of backlight drive circuit, it is characterised in that including：
Input block, it is used for the access of power supply；
Transformer, it includes：
First armature winding, it is electrically connected with the output end of the input block；
First secondary windings, it is coupled with first armature winding；
First assists winding, itself and first level winding coupled；
Voltage output unit, it is electrically connected with the output end of first secondary windings, and it is used to export backlight driving voltage；
Driver element is controlled, it is electrically connected with first assists winding；
Wherein, the transformer also includes the second assists winding unit, the second assists winding unit and first level
Winding coupled, the second assists winding unit is electrically connected with the control driver element, the output of first assists winding
Voltage is less than the output voltage of the second assists winding unit, and first assists winding and the second assists winding list
Member is commonly connected to the voltage controling end of the control driver element.
2. backlight drive circuit as claimed in claim 1, it is characterised in that the second assists winding unit includes：
Second auxiliary primary winding, itself and first level winding coupled；
Second auxiliary secondary winding, itself and the second auxiliary primary winding coupled, the second auxiliary secondary winding with it is described
Control the voltage controling end electrical connection of driver element.
3. backlight drive circuit as claimed in claim 2, it is characterised in that the output voltage of the second auxiliary secondary winding
More than the output voltage of first assists winding.
4. backlight drive circuit as claimed in claim 3, it is characterised in that the coil turn of the second auxiliary primary winding
More than the coil turn of first secondary windings.
5. backlight drive circuit as claimed in claim 4, it is characterised in that coil turn/institute of first secondary windings
State the first assists winding coil turn be more than the second auxiliary primary winding coil turn/second auxiliary secondary around
The coil turn of group.
6. the backlight drive circuit as described in claim 2-5 any one, it is characterised in that the backlight drive circuit is also wrapped
Include constant current driving unit, constant current driving unit output end respectively with the second auxiliary primary winding, the voltage are defeated
Go out unit electrical connection.
7. backlight drive circuit as claimed in claim 6, it is characterised in that also including reduction voltage circuit, the reduction voltage circuit one
End is electrically connected with the output end of the second auxiliary primary winding, and the reduction voltage circuit other end is electrically connected with constant current driving unit
Connect, the voltage of the second auxiliary primary winding output is exported to constant current driving unit after being depressured via reduction voltage circuit.
8. backlight drive circuit as claimed in claim 7, it is characterised in that the voltage output unit and the reduction voltage circuit
The voltage input end of constant current driving unit is commonly connected to, the reduction voltage circuit is exported to constant current driving unit voltage input end
Voltage exports the voltage to constant current driving unit voltage input end more than the voltage output unit.
9. backlight drive circuit as claimed in claim 7, it is characterised in that the reduction voltage circuit includes the second triode, the
35 resistance and voltage-regulator diode, the colelctor electrode of second triode electrically connect the output of the second auxiliary primary winding
End, electrically connects the 35th resistance, the base of second triode between the colelctor electrode and base stage of second triode
Pole electrically connects the negative electrode of voltage-regulator diode, and the plus earth of the voltage-regulator diode, the emitter stage of second triode is electrically connected
Connect constant current driving unit.
10. backlight drive circuit as claimed in claim 9, it is characterised in that also including the 15th diode, the 17th pole
Pipe and electric capacity, the anode of the 15th diode electrically connect the first end of the second auxiliary primary winding, the electric capacity electricity
It is connected between the anode of the 15th diode and the second end of the second auxiliary primary winding, the 17th pole
The anode of pipe electrically connects the emitter stage of the second triode, the negative electrode electrical connection constant current driving unit of the 17th diode.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710651630.9A CN107276421A (en) | 2017-08-02 | 2017-08-02 | Backlight drive circuit |
| PCT/CN2017/097872 WO2019024134A1 (en) | 2017-08-02 | 2017-08-17 | Backlight driving circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710651630.9A CN107276421A (en) | 2017-08-02 | 2017-08-02 | Backlight drive circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN107276421A true CN107276421A (en) | 2017-10-20 |
Family
ID=60074800
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710651630.9A Pending CN107276421A (en) | 2017-08-02 | 2017-08-02 | Backlight drive circuit |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN107276421A (en) |
| WO (1) | WO2019024134A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109862653A (en) * | 2018-09-14 | 2019-06-07 | 苏州瑞铬优电子科技有限公司 | A kind of illumination driving circuit for High Power Factor LED |
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| CN101832479A (en) * | 2008-12-12 | 2010-09-15 | 斯皮瑞特商业集团有限公司 | LED replacement light for fluorescent lighting fixtures |
| CN103607110A (en) * | 2013-11-01 | 2014-02-26 | 东南大学 | Rapid opening switch power supply assisting winding to carry out power supply |
| CN104010406A (en) * | 2013-02-27 | 2014-08-27 | 台达电子工业股份有限公司 | Led driver |
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|---|---|---|---|---|
| US6359795B1 (en) * | 1999-03-26 | 2002-03-19 | Sarnoff Corporation | Soft-switching power supply with auxiliary resonator |
| CN102421226B (en) * | 2011-09-06 | 2014-05-07 | 上海新进半导体制造有限公司 | LED (light-emitting diode) dimming driving circuit |
| CN102420529A (en) * | 2011-12-23 | 2012-04-18 | 崧顺电子（深圳）有限公司 | Voltage conversion circuit for forward design of auxiliary winding in flyback topology |
| CN104575401B (en) * | 2013-10-29 | 2017-02-22 | 惠科股份有限公司 | Two-in-one power source for LED backlight and LED backlight display |
| CN104009638B (en) * | 2014-06-09 | 2016-08-24 | 深圳市华星光电技术有限公司 | A kind of circuit for adjusting output voltage and method |
| CN204304785U (en) * | 2014-12-05 | 2015-04-29 | 天水华天微电子股份有限公司 | By the Switching Power Supply regulating the turn ratio to realize ultra-wide input voltage range |
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- 2017-08-02 CN CN201710651630.9A patent/CN107276421A/en active Pending
- 2017-08-17 WO PCT/CN2017/097872 patent/WO2019024134A1/en active Application Filing
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101832479A (en) * | 2008-12-12 | 2010-09-15 | 斯皮瑞特商业集团有限公司 | LED replacement light for fluorescent lighting fixtures |
| CN104010406A (en) * | 2013-02-27 | 2014-08-27 | 台达电子工业股份有限公司 | Led driver |
| CN103607110A (en) * | 2013-11-01 | 2014-02-26 | 东南大学 | Rapid opening switch power supply assisting winding to carry out power supply |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109862653A (en) * | 2018-09-14 | 2019-06-07 | 苏州瑞铬优电子科技有限公司 | A kind of illumination driving circuit for High Power Factor LED |
| CN109862653B (en) * | 2018-09-14 | 2021-09-24 | 苏州瑞铬优电子科技有限公司 | Illumination driving circuit for high-power-factor LED |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2019024134A1 (en) | 2019-02-07 |
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