CN101409044B - Backlight component and drive method thereof - Google Patents
Backlight component and drive method thereof Download PDFInfo
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- CN101409044B CN101409044B CN2007101811244A CN200710181124A CN101409044B CN 101409044 B CN101409044 B CN 101409044B CN 2007101811244 A CN2007101811244 A CN 2007101811244A CN 200710181124 A CN200710181124 A CN 200710181124A CN 101409044 B CN101409044 B CN 101409044B
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Abstract
The invention discloses a backlight module and a drive method thereof. The backlight module comprises an LED drive circuit, a DC power supply converter and a feedback compensation circuit. The LED drive circuit comprises a plurality of light-emitting elements and a plurality of dimming circuits. The backlight module divides a plurality of temperature distribution regions based on a relative relation of heat emission directions, and the region with the lowest temperature is provided with a first light-emitting element. A first feedback signal is generated at the coupling position of the first light-emitting element and a first dimming circuit. The feedback compensation circuit receives the first feedback signal and generates a voltage compensation signal. The DC power supply converter receives the voltage compensation signal, and operates according to the voltage compensation signal to provide and output an operating voltage to the LED drive circuit. Therefore, the backlight module and the drive method thereof can reduce number of the feedback signals and the feedback signal processing complexity, and enhance the system efficiency.
Description
Technical field
The invention relates to a kind of backlight assembly and driving method thereof, and particularly about a kind of light emitting diode (Light emitting diode, backlight assembly LED) and driving method thereof.
Background technology
In recent years, the backlight liquid crystal display assembly adopts the light emitting diode with long, characteristic such as efficient is high and environmental pollution is lower of life-span (Light Emitting Diode is LED) as backlight.Increasing when the liquid crystal panel of LCD, its backlight assembly also and then uses more light emitting diode that enough backlights are provided.Therefore, the circuit of driven for emitting lights diode will produce more power consumption.Please refer to Fig. 1, Fig. 1 is the Temperature Distribution graph of a relation of LED-backlit mechanism backboard 10 when thermal equilibrium.Because the LCD in general the use, its LED-backlit mechanism backboard roughly becomes vertical with desktop (or surface level), therefore under thermally equilibrated state, the heat that backlight assembly produced makes this mechanism's backboard Temperature Distribution from the bottom to top be: low toward the temperature height by temperature.
Please refer to Fig. 2, Fig. 2 is the forward conducting electric current of LED, the relativeness figure of forward voltage and environment temperature forward.Fig. 2 is painted with 3 forward curves of conducting electric current, appoints and to get wherein curve: the forward conducting electric current I FP of identical LED is in the temperature situation that rises, and the forward forward voltage of LED can rise and descend along with temperature.
Please refer to Fig. 3, Fig. 3 is the circuit diagram of traditional backlight assembly.Backlight assembly 300 comprises the LED driving circuit of N group: light-emitting component 301 to 30N couples corresponding light adjusting circuit 331 respectively to 33N.Because heat that backlight assembly produced is under thermally equilibrated state, the temperature of LED-backlit mechanism backboard can present different variations, makes that the residing environment temperature of each light-emitting component is not quite alike, and its brightness is difference to some extent also, cause easily show bad.Therefore, traditional design backlight assembly 300 is from the LED driving circuit of N group, takes out N feedback signal Vm1 to VmN and does the closed loop drive controlling, then adjusts the output of dc power converter 310.Yet the complexity that design of feedback compensating circuit 320 is handled N feedback signal Vm1 to VmN is quite high, and designs the degree of difficulty that N feedback signal can increase wiring, so the circuit cost of backlight assembly 300 also and then improves relatively.
Summary of the invention
The purpose of this invention is to provide a kind of backlight assembly, can use the feedback signal of lesser amt to do closed loop control, can reduce the complexity of design of feedback compensating circuit, also can reduce the degree of difficulty of wiring, and reduce the circuit cost of backlight assembly.
The present invention provides a kind of driving method of backlight assembly in addition, when adjusting the operating voltage of dc power converter, can use less feedback signal to do closed loop control, the temperature that can reduce backlight assembly reduces power consumption, and can promote the life-span of light emitting diode, therefore can promote the circuit performance of backlight assembly.
The present invention proposes a kind of backlight assembly, it forms a plurality of Temperature Distribution zone according to the relativeness of heat dissipation direction, one of them is the temperature lowermost extent for this a little Temperature Distribution zone, and this backlight assembly comprises LED driving circuit, dc power converter and feedback compensation circuit.LED driving circuit is in order to provide backlight and to produce first feedback signal, and LED driving circuit comprises a plurality of light-emitting components and a plurality of light adjusting circuit.These a little light-emitting components produce backlight in order to receive operating voltage, and first light-emitting component of these a little light-emitting components is configured in the temperature lowermost extent.These a little light adjusting circuits are in order to provide the drive current of these a little light-emitting components, each light adjusting circuit is coupled to one of these corresponding a little light-emitting components, and first feedback signal to be coupling of first light adjusting circuit from this a little light adjusting circuits of the first light-emitting component correspondence obtain.Dc power converter is coupled to LED driving circuit, and adjusts and output services voltage according to voltage compensation signal.The feedback compensation circuit is coupled between dc power converter and the LED driving circuit, produces voltage compensation signal in order to receive first feedback signal.
Above-mentioned backlight assembly, in one embodiment, the feedback compensation circuit comprises first error amplifier and first voltage compensator.First error amplifier receives first reference signal and first feedback signal, and relatively first reference signal obtains with first feedback signal exporting.First voltage compensator is coupled between the output terminal and dc power converter of first error amplifier, and produces and the output voltage compensation signal according to this.
Above-mentioned backlight assembly, in another embodiment, one second light-emitting component of these a little light-emitting components is configured in the temperature lowermost extent, LED driving circuit also produces one second feedback signal, obtains and second feedback signal is one second coupling of light adjusting circuit from this a little light adjusting circuits of the second light-emitting component correspondence.The feedback compensation circuit also receives second feedback signal, and produces voltage compensation signal according to the mean value of first feedback signal and second feedback signal.
From another viewpoint, the present invention proposes a kind of driving method of backlight assembly in addition.Backlight assembly comprises LED driving circuit, dc power converter and feedback compensation circuit.LED driving circuit comprises a plurality of light-emitting components and a plurality of light adjusting circuit.Driving method comprises the following steps: that backlight assembly divides a plurality of Temperature Distribution zone according to the relativeness of heat dissipation direction, and this a little Temperature Distribution zone one of them be the temperature lowermost extent; LED driving circuit produces first feedback signal, and first feedback signal to be the place of coupling of first light adjusting circuit of these a little light adjusting circuits of the first light-emitting component correspondence of from then on a little light-emitting components obtain, and first light-emitting component is configured in the temperature lowermost extent; The feedback compensation circuit receives first feedback signal, and produces voltage compensation signal; Dc power converter receives voltage compensation signal, and according to voltage compensation signal operate, provide and output services voltage to LED driving circuit.
The driving method of above-mentioned backlight assembly, in one embodiment, the feedback compensation circuit is coupled between dc power converter and the LED driving circuit, and it produces voltage compensation signal in order to receive first feedback signal.
The driving method of above-mentioned backlight assembly also comprises the following steps in another embodiment.LED driving circuit produces second feedback signal, and second feedback signal to be the place of coupling of second light adjusting circuit of these a little light adjusting circuits of the second light-emitting component correspondence of from then on a little light-emitting components obtain, and second light-emitting component is configured in the temperature lowermost extent.The feedback compensation circuit receives second feedback signal, and produces voltage compensation signal according to the mean value of first feedback signal and second feedback signal.
Backlight assembly of the present invention is divided a plurality of Temperature Distribution zone according to heat radiation, the feedback compensation circuit of backlight assembly is to deal with from temperature lowermost extent acquisition feedback signal, and produce bucking voltage and adjust operating voltage to dc power converter, thereby the quantity of simplification feedback compensation circuit receiving feedback signals, replace and compared originally and will more a plurality of feedback signals be sent to the feedback compensation circuit.Therefore, the present invention can reduce the feedback signal quantity between feedback compensation circuit and the LED driving circuit.Backlight assembly of the present invention and driving method thereof can reduce the life-span of the complexity of design of feedback compensating circuit, the degree of difficulty that reduces wiring, the circuit cost that reduces backlight assembly, the power consumption that reduces backlight assembly, the temperature that reduces the LED backlight assembly, lifting light emitting diode, and then can promote the circuit performance of entire backlight assembly.
For above-mentioned and other purposes, feature and advantage of the present invention can be become apparent, embodiments of the invention cited below particularly, and conjunction with figs. is described in detail below.
Description of drawings
Fig. 1 is the Temperature Distribution graph of a relation of LED-backlit mechanism backboard when thermal equilibrium.
Fig. 2 is the forward conducting electric current of LED, the relativeness figure of forward voltage and environment temperature forward.
Fig. 3 is the circuit diagram of traditional backlight assembly.
Fig. 4 (a) divides a plurality of Temperature Distribution areal maps for LED backlight mechanism backboard according to an embodiment of the invention.
Fig. 4 (b) is the backlight assembly circuit diagram according to a plurality of Temperature Distribution zone of Fig. 4 (a).
Fig. 4 (c) is the back light member of backlight assembly of Fig. 4 (b) and the relativeness figure of LED-backlit mechanism backboard.
Fig. 4 (d) opens the circuit controls Organization Chart for analysis chart 4 (b).
Cooling and heating machine electric characteristic figure when Fig. 4 (e) opens circuit controls for simulation.
Fig. 4 (f) is the Organization Chart of simulation closed loop control.
Fig. 4 (g) is respectively to temperature height and each voltage comparison diagram of the low zone of temperature being made feedback compensation.
Fig. 5 (a) to Fig. 5 (c) be Temperature Distribution areal map according to another embodiment of the present invention.
Fig. 5 (d) is the circuit diagram according to the backlight assembly of another embodiment of the present invention.
Embodiment
This case inventor is because the circuit design of traditional backlight assembly, and its complicacy is quite high, by analysis, various situations of simulation and produce the present invention.One of principal character of the present invention is to deal with from temperature lowermost extent acquisition feedback signal.Below begin to illustrate various embodiments of the present invention.
Please refer to Fig. 4 (a), (Lightemitting diode, LED) the back-light mechanism backboard is divided a plurality of Temperature Distribution areal maps to Fig. 4 (a) for light emitting diode according to an embodiment of the invention.In order to alleviate complexity, tradition needs N feedback signal Vm1 to VmN, and reduces the required feedback signal of conventional art in embodiments of the present invention.At first, backlight assembly forms a plurality of Temperature Distribution zone according to the relativeness of heat dissipation direction.In Fig. 4 (a), backlight assembly is configured on the LED-backlit mechanism backboard 40, and LED-backlit mechanism backboard 40 is divided 3 Temperature Distribution zones, be respectively T1 district, T2 district and T3 district.This technology has knows that usually the knowledgeable should understand, and divides the Temperature Distribution zone and can come the zoning according to simulation of Heat Balance or experimental result in advance, so do not limit the quantity of dividing the Temperature Distribution zone.Suppose general situation, LED-backlit mechanism backboard 40 stands on the situation of desktop, and the heat radiation aperture being arranged around the LED-backlit mechanism backboard 40 or have only has the heat radiation aperture topmost.Therefore, the LCD in the use is when thermal equilibrium, and LED-backlit mechanism backboard 40 can be the hottest in the T1 district, secondly be the T2 district, and the temperature province in T3 district is minimum.Design is during backlight assembly, owing to be subjected to the environment temperature difference, so the forward forward voltage of the LED in each district can be different at the LED in each district for it.In the forward forward voltage minimum of the LED in T1 district, in the forward forward voltage maximum of the LED in T3 district, and that the forward forward voltage of the LED in T2 district occupies is time big.
Hold above-mentioned, divide a lot of temperature province after, then must reduce the quantity of feedback signal.The practice that this desire will reduce feedback signal quantity is from a certain zone acquisition feedback signal, so will reduce much in the complexity of handling feedback signal, for verifying feasible Fig. 4 of please refer to (b), and carries out followingly respectively testing.Fig. 4 (b) is the backlight assembly circuit diagram according to a plurality of Temperature Distribution zone of Fig. 4 (a).Backlight assembly 42 has comprised T1 district light-emitting component, T2 district light-emitting component and T3 district light-emitting component.Wherein, T1 district light-emitting component comprises light- emitting component 41a, 41b ..., T2 district light-emitting component comprises light- emitting component 43a, 43b ..., T3 district light-emitting component comprises light-emitting component 45a, 45b ..., and each light-emitting component comprises a light emitting diode at least.
For analyze backlight assembly 42 in the T1 district the various situations to the T3 district: when first kind of situation was cold machine, circuit controls was opened in simulation; When second kind of situation is hot machine, simulation T1 district open circuit controls; When the third situation is hot machine, simulation T3 district open circuit controls.The distribution scenario of each light-emitting component of Fig. 4 (b) on the LED-backlit mechanism backboard 40 of Fig. 4 (a) can be with reference to figure 4 (c).Fig. 4 (c) is the back light member of backlight assembly 42 and the relativeness figure of LED-backlit mechanism backboard.
At this, carry out the analysis of above-mentioned various situations, suppose light-emitting component 41a～41c, 43a～43c, 45a～45c, and light-emitting component uses identical LED, and quantity is identical, and LED is connected.Please refer to Fig. 4 (d).Fig. 4 (d) opens the circuit controls Organization Chart for analysis chart 4 (b).Dc power converter 48a produces operating voltage VLED and comes driven light-emitting element 46, just lights the driving power of LED 1～LEDN.Forward forward voltage (the Vf of each light emitting diode
1, Vf
2..., Vf
N) summation be the forward forward voltage Vf_total of light-emitting component 46.Light adjusting circuit 47 comprises switch SW and constant current source I1.Voltage Vm is from the couple generation of light-emitting component 46 with light adjusting circuit 47, and relational expression is VLED=Vf_total+Vm.(suppose that light-emitting component 46 is to use 4 light emitting diodes at present, and the forward forward voltage of each light emitting diode equals 2V.)
When first kind of situation was cold machine, circuit controls was opened in simulation, so operating voltage VLED fixes.Provide a data information at this, when constant current source I1 is 20mA, when operating voltage VLED was 9V, forward forward voltage Vf_total was 8V, and voltage Vm is 1V, and its Vm consumed power is 20mV.
Then, when second kind of situation is hot machine, simulation T1 district open circuit controls.Provide a data information at this, when constant current source I1 is 20mA, when operating voltage VLED was 9V, forward forward voltage Vf_total was 6.8V, and voltage Vm is 2.2V, and its Vm consumed power is 44mV.Therefore, the forward forward voltage of every light emitting diode drops to 0.3V.
When the third situation is hot machine, simulation T3 district open circuit controls.Provide a data information at this, when constant current source I1 is 20mA, when operating voltage VLED was 9V, forward forward voltage Vf_total was 7.6V, and voltage Vm is 1.4V, and its Vm consumed power is 28mV.Therefore, the forward forward voltage of every light emitting diode drops to 0.1V.
Above-mentioned three kinds of analog case please refer to Fig. 4 (e) now behind the disposal data.Therefore learn that light-emitting component 46 makes that except rising because of system temperature forward forward voltage Vf_total descends, and makes voltage Vm rise, this causes the power consumption of switch SW to become big, makes power loss increase, and makes the efficiency of element variation.
Next carry out the 4th kind of situation and the 5th kind of situation simulation.When the 4th kind of situation was hot machine, the feedback signal in simulation acquisition T1 district was done the closed loop and is controlled; When the 5th kind of situation was hot machine, the feedback signal in simulation acquisition T3 district was done the closed loop and is controlled.Wherein, the 4th and the 5th kind of situation for only to making FEEDBACK CONTROL in a Temperature Distribution district, and two districts do not make FEEDBACK CONTROL in addition.At the mean value of the 4th kind of situation acquisition feedback signal Vm1a or Vm1b or negate feedback signal Vm1a and Vm1b, at the mean value of above-mentioned the 5th kind of situation acquisition feedback signal Vm3a or Vm3b or negate feedback signal Vm3a and Vm3b.
Please refer to Fig. 4 (f), Fig. 4 (f) is analysis chart 4 (b), the Organization Chart of the closed loop control when simulating hot machine.Originally ready-made at the voltage Vm of Fig. 4 (d) is the feedback signal of Fig. 4 (f).Light-emitting component 46 has used 4 identical light emitting diodes.Feedback compensation circuit 49 comprises error amplifier 49b and voltage compensator 49a, and voltage compensator 49a is coupled between error amplifier 49b and the dc power converter 48b.An error amplifier 49b receiving feedback signals Vm and a reference signal Vref, voltage compensator 49a then produce a voltage compensation signal 49c to dc power converter 48b.Dc power converter 48b adjusts and output services voltage VLED according to voltage compensation signal 49c.When the 4th kind of situation was hot machine, the feedback signal in simulation acquisition T1 district was done closed loop control, provides a data information at this, and when constant current source I1 is 20mA, when the operating voltage VLED of script was 9V, the operating voltage VLED after the compensation was 7.8V.The forward forward voltage Vf_total in T1 district is 6.8V, therefore the voltage Vm in T1 district is 1V, but the forward forward voltage Vf_total in T3 district is 7.6V, so cause the operating voltage deficiency of the light-emitting component of temperature lower region (T3 zone), makes the light emitting diode instability.
Then, when the 5th kind of situation was hot machine, the feedback signal in simulation acquisition T3 district was done closed loop control, provides a data information at this, and when constant current source I1 is 20mA, when the operating voltage VLED of script was 9V, the operating voltage VLED after the compensation was 8.6V.The forward forward voltage Vf_total in T3 district is 7.6V, so the voltage Vm in T3 district is 1.0V; And the T1 district forward forward voltage Vf_total be 6.8V, the voltage Vm in T1 district is 1.8V.So when operating voltage VLED down is adjusted to 8.6V, can contain the driving circuit of Fig. 4 (b) backlight assembly 42.The analog case of above-mentioned the 4th kind and the 5th kind situation, now please refer to Fig. 4 (g) behind the disposal data, wherein make feedback compensation with the higher zone of temperature, voltage difference between the forward forward voltage Vf_total of this adjusted operating voltage VLED and temperature lower region is too little, easily causes the task performance instability of light-emitting component.Proved that backlight assembly of the present invention and its driving method adopt the feedback signal of temperature lowermost extent (being the T3 district at this embodiment), the adjustment result who is done has reached Expected Results really.Therefore, the practice from " temperature lowermost extent " (T3 zone) acquisition feedback signal is feasible.In the present embodiment, the complexity of feedback compensation processing of circuit feedback signal can be reduced to below 1/3rd.
Please refer to Fig. 5 (a).Fig. 5 (a) is the Temperature Distribution areal map according to another embodiment of the present invention.We are divided into nine zones with LED-backlit mechanism backboard 50, as A1 district～A3 district, B1 district～B3 district and the C1 district～C3 district of figure.Suppose general situation, LED-backlit mechanism backboard 50 stands on the situation of desktop, and the heat radiation aperture being arranged around the LED-backlit mechanism backboard 50 or have only has the heat radiation aperture topmost.Therefore, the A1 district is the highest to the temperature in A3 district, and the temperature in B1 district to B3 district is inferior high, and the temperature in C1 district to C3 district can be minimum.Backlight assembly can be according to the Temperature Distribution situation of LED-backlit mechanism backboard 50, from being positioned at C1 district～one of them district, C3 district; get the acquisition point that is configured in its regional light-emitting component and make FEEDBACK CONTROL, adjust the co-operation voltage of all light-emitting components according to the feedback signal of acquisition point.Certainly; this technology has knows that usually the knowledgeable should understand; can also get the mean value of a plurality of acquisition points and do FEEDBACK CONTROL from being arranged in C1 district～C3 district, not depart under spirit of the present invention and the scope, protection scope of the present invention should be not limited to embodiment and disclose.
Please refer to Fig. 5 (b).Fig. 5 (b) is the Temperature Distribution areal map according to another embodiment of the present invention.We are divided into nine zones with LED-backlit mechanism backboard 50, as A1 district～A3 district, B1 district～B3 district and the C1 district～C3 district of Fig. 5 (a), but on the backboard in this C1 district and C3 district finned in addition.Therefore, when thermal equilibrium, the temperature in C1 district and C3 district is minimum.Backlight assembly can be made FEEDBACK CONTROL from being arranged in C1 district and C3 district, respectively getting an acquisition point that is configured in its regional light-emitting component, according to the feedback signal mean value of two acquisitions point, adjusts the co-operation voltage of all light-emitting components again; Or an acquisition point that only captures the light-emitting component in C1 district or C3 district makes FEEDBACK CONTROL, adjusts the co-operation voltage of all light-emitting components again.
Please refer to Fig. 5 (c).Fig. 5 (c) is the Temperature Distribution areal map according to another embodiment of the present invention.This is similar with the practice of Fig. 5 (b), in like manner can push away, and installs fan additional in the C1 district and the C3 district of LED-backlit mechanism backboard 50, when thermal equilibrium, makes that the temperature in C1 district and C3 district is minimum.Therefore, backlight assembly can be made FEEDBACK CONTROL from being arranged in C1 district and C3 district, respectively getting an acquisition point that is configured in its regional light-emitting component, according to the feedback signal mean value of two acquisitions point, adjusts the co-operation voltage of all light-emitting components again; Or an acquisition point that only captures the light-emitting component in C1 district or C3 district makes FEEDBACK CONTROL, adjusts the co-operation voltage of all light-emitting components again.
By the explanation of Fig. 5 (b) with Fig. 5 (c), this technology has knows that usually the knowledgeable should understand heat radiator or fan guarantees that C1 district and C3 are the temperature lowermost extent, can certainly use water cooling plant or other heat dissipating methods to reach.The zone that temperature is minimum is the heat dissipation design of relative and backboard.When the symmetry of considering average heat radiation, then can respectively there be a district in the zone that temperature is minimum at the dual-side of backboard.In addition, also do not limit with using heat abstractor quantity at dividing temperature province quantity, dividing temperature province quantity has many kind combinations with using heat abstractor quantity.Therefore do not departing under spirit of the present invention and the scope, protection scope of the present invention should be not limited to embodiment and disclose.
Please refer to Fig. 5 (d).Fig. 5 (d) is the circuit diagram according to the backlight assembly of another embodiment of the present invention.Backlight assembly 500 is configured on the LED-backlit mechanism backboard 50 with heat abstractor as Fig. 5 (b) or Fig. 5 (c).Backlight assembly 500 forms a plurality of Temperature Distribution zone according to the relativeness of heat dissipation direction, as Fig. 5 (a).Emphasis of the present invention is from " temperature lowermost extent " acquisition feedback signal, shown in Fig. 5 (a) and Fig. 5 (d): C1 district and C3 district are the temperature lowermost extent, and capture the first feedback signal Vmc1, the second feedback signal Vmc3 from C1 district and C3 and do the closed loop and control.
Each light adjusting circuit can provide the drive current of its corresponding light-emitting component, light-emitting component can produce backlight after receiving operating voltage VLED, and first light-emitting component 510 of these a little light-emitting components, second light-emitting component 511 are configured in the temperature lowermost extent, and wherein the temperature lowermost extent also disposes heat abstractor.The first feedback signal Vmc1 is that first the coupling of light adjusting circuit 512 from these a little light adjusting circuits of first light-emitting component, 510 correspondences obtains.Second feedback signal is that one second coupling of light adjusting circuit 514 from these a little light adjusting circuits of second light-emitting component, 511 correspondences obtains.Therefore, LED driving circuit 52 also produces the first feedback signal Vmc1 and the second feedback signal Vmc3.
Feedback compensation circuit 55 comprises error amplifier 59 and voltage compensator 57.Error amplifier 59 receives reference signal Vref, the first feedback signal Vmc1 and the second feedback signal Vmc3, and the mean value of comparison reference signal Vref, the first feedback signal Vmc1 and the second feedback signal Vmc3 and obtain exporting.Wherein, can adopt two feedback signal mean values and reference signal Vref to make comparisons, can certainly only adopt first or second feedback signal to come comparison reference signal Vref for fear of feedback signal is inaccurate.Voltage compensator 57 is coupled between the output and dc power converter 51 of error amplifier 59, and produces according to this and output one voltage compensation signal 53.
Dc power converter 51 can be adjusted input and the power supply that is output as different DC potential with pulse width modulation mode, and export an operating voltage VLED according to voltage compensation signal 53.The pattern of this dc power converter 51 can just repeat no more at this for traditional voltage boosting dc power supply changeover device, decompression DC power supply changeover device or buck dc power converter.
We come the difference of comparison diagram 3 and Fig. 5 (d), and in the conventional art, the backlight assembly 300 of Fig. 3 is the feedback signals that adopt quite a lot of quantity, and in the backlight assembly 300 of heavy feedback signal quantity, it is excessive to make traditional feedback compensation circuit 320 therefore to load.It is simple that the backlight assembly 500 of Fig. 5 (d), the structure of its feedback compensation circuit 55 just seem relatively down, and feedback compensation circuit 55 handled feedback signal quantity seem considerably less compared to feedback compensation circuit 320.Therefore, the feedback signal quantity of the embodiment of the invention reduces, and can lower the complexity of design of feedback compensating circuit 55, also reduces the degree of difficulty of wiring, and the circuit cost of backlight assembly 500 also and then reduces compared to backlight assembly 300.
Except the backlight assembly of the foregoing description, the present invention also comprises a kind of driving method of backlight assembly of correspondence.Usually know and by the backlight assembly embodiment of front, should implement the driving method of backlight assembly of the present invention for the knowledgeable for having, therefore will not give unnecessary details at correlative technology field of the present invention.
Comprehensively above-mentioned, the present invention is because of simplifying the quantity of feedback compensation circuit institute receiving feedback signals, and backlight assembly adopts from " temperature lowermost extent " acquisition feedback signal and does closed loop control, replaces and will transmit quite a plurality of feedback compensation circuit that feed back signal to originally.Therefore, the present invention can reduce feedback signal quantity and the circuit between feedback compensation circuit and the LED driving circuit.Backlight assembly of the present invention and driving method thereof have the following advantages at least:
1. use less feedback signal to do closed loop control;
2. reduce the complexity of design of feedback compensating circuit;
3. reduce the degree of difficulty of wiring;
4. reduce the circuit cost of backlight assembly;
5. reduce the power consumption of backlight assembly;
6. reduce the temperature of LED backlight assembly;
7 promote the life-span of light emitting diode;
8. significantly promote the circuit performance of backlight assembly.
Though the present invention discloses as above with embodiment; right its is not in order to limit the present invention; have in the technical field under any and know the knowledgeable usually; without departing from the spirit and scope of the present invention; when can doing a little change and retouching, so protection scope of the present invention is when with being as the criterion that claim was defined.
Claims (22)
1. backlight assembly, this backlight assembly forms a plurality of Temperature Distribution zone according to the relativeness of heat dissipation direction, and one of them is a temperature lowermost extent for those Temperature Distribution zones, and this backlight assembly comprises:
One LED driving circuit, in order to backlight to be provided and to produce one first feedback signal, this LED driving circuit comprises:
A plurality of light-emitting components produce backlight in order to receive an operating voltage, and one first light-emitting component of those light-emitting components is configured in this temperature lowermost extent; And
A plurality of light adjusting circuits, in order to the drive current of those light-emitting components to be provided, each light adjusting circuit is coupled to one of those corresponding light-emitting components, and this first feedback signal to be one first coupling of light adjusting circuit from those light adjusting circuits of this first light-emitting component correspondence obtain;
One direct current power supply changeover device is coupled to this LED driving circuit, and adjusts and export this operating voltage according to a voltage compensation signal; And
One feedback compensation circuit is coupled between this dc power converter and this LED driving circuit, in order to receive this first feedback signal, produces this voltage compensation signal according to this.
2. backlight assembly as claimed in claim 1 is characterized in that, this feedback compensation circuit comprises:
One first error amplifier receives one first reference signal and this first feedback signal, and relatively this first reference signal and this first feedback signal and obtain output; And
One first voltage compensator is coupled between the output and this dc power converter of this first error amplifier, and produces according to this and this voltage compensation signal of output.
3. backlight assembly as claimed in claim 1 is characterized in that, this temperature lowermost extent disposes a heat abstractor, and wherein this heat abstractor is a heat radiator, a fan or a water cooling plant.
4. backlight assembly as claimed in claim 1 is characterized in that, in those light-emitting components, each light-emitting component comprises a light emitting diode at least.
5. backlight assembly as claimed in claim 1 is characterized in that, in those light adjusting circuits, each light adjusting circuit comprises:
One switch, one end are coupled to one of those corresponding light-emitting components; And
One constant current source is coupled between this switch and the ground connection.
6. backlight assembly as claimed in claim 1, it is characterized in that, one second light-emitting component of those light-emitting components is configured in this temperature lowermost extent, this LED driving circuit also produces one second feedback signal, obtains and this second feedback signal is one second coupling of light adjusting circuit from those light adjusting circuits of this second light-emitting component correspondence.
7. backlight assembly as claimed in claim 6 is characterized in that, this feedback compensation circuit also receives this second feedback signal, and produces this voltage compensation signal according to the mean value of this first feedback signal and this second feedback signal.
8. backlight assembly as claimed in claim 6 is characterized in that, this feedback compensation circuit comprises:
One second error amplifier receives one second reference signal, this first feedback signal and this second feedback signal, and relatively this first reference signal, this first feedback signal and this second feedback signal mean value and obtain output; And
One second voltage compensator is coupled between the output and this dc power converter of this second error amplifier, and produces according to this and this voltage compensation signal of output.
9. backlight assembly as claimed in claim 1 is characterized in that this dc power converter is adjusted this operating voltage with pulse width modulation mode.
10. backlight assembly as claimed in claim 1 is characterized in that, this dc power converter is a voltage boosting dc power supply changeover device, a decompression DC power supply changeover device or a buck dc power converter.
11. the driving method of a backlight assembly, this backlight assembly comprises a LED driving circuit, a direct current power supply changeover device and a feedback compensation circuit, this LED driving circuit comprises a plurality of light-emitting components and a plurality of light adjusting circuit, and this driving method comprises:
A. this backlight assembly is divided a plurality of Temperature Distribution zone according to the relativeness of heat dissipation direction, and those Temperature Distribution zone one of them be a temperature lowermost extent;
B. this LED driving circuit produces one first feedback signal, obtain and this first feedback signal is one first coupling of light adjusting circuit from those light adjusting circuits of one first light-emitting component correspondence of those light-emitting components, and this first light-emitting component is configured in this temperature lowermost extent;
C. this feedback compensation circuit receives this first feedback signal, and produces a voltage compensation signal; And
D. this dc power converter receives this voltage compensation signal, and operates according to this voltage compensation signal, provides and exports an operating voltage to this LED driving circuit.
12. the driving method of backlight assembly as claimed in claim 11, it is characterized in that, those light-emitting components receive this operating voltage and produce backlight, and those light adjusting circuits are coupled to those light-emitting components, and each light adjusting circuit is coupled to one of those corresponding light-emitting components, and those light adjusting circuits are in order to provide the drive current of those light-emitting components.
13. the driving method of backlight assembly as claimed in claim 11, it is characterized in that, this feedback compensation circuit is coupled between this dc power converter and this LED driving circuit, in order to receive this first feedback signal, produces this voltage compensation signal according to this.
14. the driving method of backlight assembly as claimed in claim 11 is characterized in that, this dc power converter is coupled to this LED driving circuit, and adjusts and export this operating voltage according to this voltage compensation signal.
15. the driving method of backlight assembly as claimed in claim 11 is characterized in that, this feedback compensation circuit comprises:
One first error amplifier receives one first reference signal and this first feedback signal, and relatively this second reference signal and this first feedback signal and obtain output; And
One first voltage compensator is coupled between the output and this dc power converter of this first error amplifier, and produces according to this and this voltage compensation signal of output.
16. the driving method of backlight assembly as claimed in claim 11 is characterized in that, also comprises:
B1. this LED driving circuit produces one second feedback signal, obtain and this second feedback signal is one second coupling of light adjusting circuit from those light adjusting circuits of one second light-emitting component correspondence of those light-emitting components, and this second light-emitting component is configured in this temperature lowermost extent; And
C1. this feedback compensation circuit receives this second feedback signal, and produces this voltage compensation signal according to the mean value of this first feedback signal and this second feedback signal.
17. the driving method of backlight assembly as claimed in claim 16 is characterized in that, this feedback compensation circuit comprises:
One second error amplifier receives one second reference signal, this first feedback signal and this second feedback signal, and relatively this second reference signal, this first feedback signal and this second feedback signal mean value and obtain output; And
One second voltage compensator is coupled between the output and this dc power converter of this second error amplifier, and produces according to this and this voltage compensation signal of output.
18. the driving method of backlight assembly as claimed in claim 11 is characterized in that, this temperature lowermost extent disposes a heat abstractor, and wherein this heat abstractor is a heat radiator, a fan or a water cooling plant.
19. the driving method of backlight assembly as claimed in claim 11 is characterized in that, in those light-emitting components, each light-emitting component comprises a light emitting diode at least.
20. the driving method of backlight assembly as claimed in claim 11 is characterized in that, in those light adjusting circuits, each light adjusting circuit comprises:
One switch, one end are coupled to one of those corresponding light-emitting components; And
One constant current source is coupled between this switch and the ground connection.
21. the driving method of backlight assembly as claimed in claim 11 is characterized in that, this dc power converter is adjusted this operating voltage with pulse width modulation mode.
22. the driving method of backlight assembly as claimed in claim 11 is characterized in that, this dc power converter is a voltage boosting dc power supply changeover device, a decompression DC power supply changeover device or a buck dc power converter.
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| Application Number | Priority Date | Filing Date | Title |
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| CN2007101811244A CN101409044B (en) | 2007-10-08 | 2007-10-08 | Backlight component and drive method thereof |
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| CN2007101811244A CN101409044B (en) | 2007-10-08 | 2007-10-08 | Backlight component and drive method thereof |
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| CN101409044B true CN101409044B (en) | 2011-07-13 |
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Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101990337B (en) * | 2009-08-03 | 2014-03-26 | 联咏科技股份有限公司 | Light source drive device capable of dynamically maintaining constant current drive and related method thereof |
| CN101998725A (en) * | 2009-08-24 | 2011-03-30 | 华映视讯（吴江）有限公司 | Drive circuit of light-emitting diode |
| CN101763838B (en) * | 2010-01-15 | 2013-11-06 | 友达光电股份有限公司 | Backlight module and method for setting drive current thereof |
| CN101950541B (en) * | 2010-07-12 | 2013-03-27 | 深圳市华星光电技术有限公司 | Backlight module and liquid crystal display |
| CN102705753B (en) * | 2012-04-28 | 2014-09-17 | 深圳市兆驰股份有限公司 | Display device and backlight module thereof |
| CN109699107B (en) * | 2019-02-15 | 2021-02-19 | 上海艾为电子技术股份有限公司 | Charging circuit and LED drive circuit |
| CN110299113B (en) * | 2019-05-09 | 2020-12-11 | 京东方科技集团股份有限公司 | Backlight driving system, backlight driving method and display device |
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| CN1619606A (en) * | 2003-11-21 | 2005-05-25 | 株式会社日立显示器 | Image display device |
| CN1648976A (en) * | 2004-01-30 | 2005-08-03 | Lg电子株式会社 | Contrast compensating apparatus for PDP module and method thereof |
| CN1721943A (en) * | 2004-07-12 | 2006-01-18 | 索尼株式会社 | Display unit and backlight unit |
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| CN1619606A (en) * | 2003-11-21 | 2005-05-25 | 株式会社日立显示器 | Image display device |
| CN1648976A (en) * | 2004-01-30 | 2005-08-03 | Lg电子株式会社 | Contrast compensating apparatus for PDP module and method thereof |
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