CN101727805A - Drive circuit of light source - Google Patents

Abstract

A drive circuit of a light source comprises a gray scale recognition unit, a parameter optimization module, a parameter calculation unit, a light-regulation control unit ad a drive unit. The gray scale recognition unit is used for capturing the maximal gray scale values individually corresponding to a plurality of data blocks in image data. The parameter optimization module generates an optimized period value according to the ratio of a standard current value to a specific current value. The parameter calculation unit obtains a specific value according to the optimized period value and the maximal gray scale values of the image and multiplies the maximal gray scale values of the data blocks by the specific value respectively to obtain a plurality of working period values. The light-regulation control unit generates a plurality of light-regulation control signals according to the working period values and the specific current value. Thus, the drive unit generates a plurality of drive pulse waves according to the light-regulation control signals.

Description

Light source driving circuit

Technical field

The invention relates to a kind of light source driving circuit, and particularly reach the light source driving circuit that reduces power consumption relevant for a kind of optimization of parameter of utilizing.

Background technology

In recent years, LCD (LCD) with frivolous volume with than advantages such as low power consumptions, be widely used in the various electronic products that need display device.LCD system utilize liquid crystal material revolve optical activity (optical activity) and photoelectric characteristic is come show image.Yet because liquid crystal material itself do not have luminous function, so LCD must dispose a backlight module, required light source when show image is provided.

Backlight module is in providing the process of light source, and it is to utilize a light source driving circuit to come the driven for emitting lights assembly, produces light source to cause luminescence component.In addition, light source driving circuit can meet the character such as panel luminance, image quality and color saturation of LCD more in order to the characteristics such as dimming scope, luminance brightness and light uniformity coefficient of control luminescence component with the light source that causes backlight module to be provided.

Figure 1A illustrates the circuit block diagram into known light source driving circuit.With reference to Figure 1A, known light source driving circuit 100 comprises gray scale recognition unit 110, parameter calculation unit 120, dimming control unit 130 and driver element 140.At this, gray scale recognition unit 110 can be divided into an image data Data1 most data blocks, and captures the maximum gray value of each block.Wherein, if the resolution of image data Data1 is 8, and its pairing picture maximum gray value is 255.

Afterwards, as the formula (1), parameter calculation unit 120 can calculate the pairing separately work period of each block according to the maximum gray value of each block.

$D_j=\frac{{\mathrm{VG}}_j}{255}*100\%---\left(1\right)$

Wherein, D _jBe j pairing work period of data blocks, VG _jBe j the pairing maximum gray value of data block, j is a positive integer.

Moreover dimming control unit 130 can be according to a pairing work period of block and a standard current value I _Spec, and produce most brightness adjustment control signals.By this, driver element 140 can produce plurality of drive pulse wave PU according to these brightness adjustment control signals ₁₁～PU _1n, with most the light emitting diodes (not illustrating) in backlight module of drive arrangements in regular turn.Wherein, the electric current of described light emitting diode is neither greater than the standard current value I _Spec

It should be noted that owing to drive pulse wave PU ₁₁～PU _1nWork period between 0% to 100%, therefore when the maximum gray value of block is 255, it is 100% driving pulse wave that driver element 140 will produce the work period.At this moment, shown in Figure 1B, in each display cycle T, the electric current of the light emitting diode of flowing through all will maintain the standard current value I _Spec, and produce the backlight of high-high brightness by this.

Yet when the known technology desire improved the high-high brightness of backlight, known light source driving circuit 100 must improve the standard current value I _Spec, drive pulse wave PU to improve by this ₁₁～PU _1nVoltage quasi position.At this moment, the power consumption of known light source driving circuit 100 will relatively be raised.In addition, the surface temperature (junction temperature) that connects of light emitting diode also will be along with the standard current value I _SpecRaising and promote, and then reduce the serviceable life of backlight module.

Summary of the invention

The invention provides a kind of light source driving circuit, in order to reduce the power consumption of circuit itself.

The invention provides a kind of light source driving circuit, in order to reduce the system cost of backlight module.

The present invention proposes a kind of light source driving circuit, in order to drive most luminescence components.Light source driving circuit comprises a gray scale recognition unit, a parameter optimization module, a parameter calculation unit, a dimming control unit and a driver element.Wherein, gray scale recognition unit is in order to being divided into an image data most data blocks, and captures the pairing separately maximum gray value of described block.Afterwards, parameter optimization module can produce an optimization periodic quantity according to the ratio of a standard current value and a specific current value, and wherein the standard current value is less than specific current value.

On the other hand, parameter calculation unit can be according to optimization periodic quantity and a picture maximum gray value and is obtained a certain ratio.Afterwards, parameter calculation unit more multiplies each other the maximum gray value of described block respectively and obtains most working period values with certain ratio.By this, the dimming control unit meeting is according to described working period values and specific current value, and most brightness adjustment control signals of generation.Driver element then produces the required plurality of drive pulse wave of driven for emitting lights assembly according to described brightness adjustment control signal.

In one embodiment of this invention, the work period of above-mentioned driving pulse wave is equal to described working period values respectively, and the electric current of the described luminescence component of flowing through is neither greater than specific current value.

The present invention proposes a kind of light source driving circuit in addition, in order to drive most luminescence components.Light source driving circuit comprises a gray scale recognition unit, a parameter optimization module, a parameter calculation unit, a dimming control unit and a driver element.Wherein, gray scale recognition unit is in order to being divided into an image data most data blocks, and captures the pairing separately maximum gray value of described block.Moreover parameter optimization module can produce an optimization current value according to the ratio of a standard current value and a specific period value, and wherein the specific period value is less than 1.

On the other hand, parameter calculation unit can be according to optimization current value and a picture maximum gray value and is obtained a certain ratio.In addition, parameter calculation unit more multiplies each other the maximum gray value of described block respectively and obtains most current values with certain ratio.By this, the dimming control unit meeting is according to described current value and specific period value, and most brightness adjustment control signals of generation.Driver element is then in order to produce the required plurality of drive pulse wave of driven for emitting lights assembly according to described brightness adjustment control signal.

In one embodiment of this invention, the work period of above-mentioned driving pulse wave is neither greater than the specific period value, and the electric current of the described luminescence component of flowing through is equal to described current value respectively.

What deserves to be mentioned is that above-mentioned light source driving circuit is applicable to a backlight module.In addition, described luminescence component is configured in the backlight module, and is made of a light emitting diode respectively.

The present invention utilizes parameter optimization module to produce optimization periodic quantity or optimization current value.By this, light source driving circuit can be adjusted the work period or the voltage quasi position that drive pulse wave according to optimization periodic quantity or optimization current value.Wherein, the work period that drives pulse wave is all less than 100%, and the electric current of luminescence component is all greater than the standard current value.Thus, with known technology compare following, the present invention need not promote the consumed power of circuit itself, just can increase the high-high brightness of luminescence component, and and then helps to reduce the system cost of backlight module.

For above-mentioned feature and advantage of the present invention can be become apparent, preferred embodiment cited below particularly, and cooperate appended graphicly, be described in detail below.

Description of drawings

Figure 1A is the circuit block diagram of known light source driving circuit;

Figure 1B is the current waveform figure in order to explanation Figure 1A embodiment;

Fig. 2 A is the circuit framework figure according to the light source driving circuit of one embodiment of the invention;

The current waveform figure of the following luminescence component that Fig. 2 B compares for Fig. 2 A embodiment and known technology;

Fig. 3 A is the circuit framework figure according to the light source driving circuit of another embodiment of the present invention;

The current waveform figure of the following luminescence component that Fig. 3 B compares for Fig. 3 A embodiment and known technology.

Embodiment

Before spirit of the present invention being described, suppose that at first the cited light source driving circuit of each embodiment is applicable to a backlight module with embodiment.In addition, the described light source driving circuit of each embodiment more in order to most the luminescence components (do not show) of drive arrangements in backlight module, produces light source to cause described luminescence component.Wherein, described luminescence component can be made of a light emitting diode respectively.Right above-mentioned hypothesis is not in order to limit the present invention, to be familiar with this operator and can to change the application kenel of light source driving circuit according to spirit of the present invention yet.

Fig. 2 A is the circuit framework figure according to the light source driving circuit of one embodiment of the invention.With reference to Fig. 2 A, light source driving circuit 200 comprises gray scale recognition unit 210, parameter calculation unit 220, dimming control unit 230, driver element 240 and parameter optimization module 250.Wherein, gray scale recognition unit 210 is electrically connected to parameter calculation unit 220 respectively with parameter optimization module 250.Parameter calculation unit 220 is electrically connected to dimming control unit 230.Dimming control unit 230 then is electrically connected to driver element 240.

In whole start, gray scale recognition unit 210 is in order to be divided into an image data Data2 most data block DB ₂₁～DB _2nAfterwards, gray scale recognition unit 210 can comparison block DB ₂₁～DB _2nIncluded separately GTG value is to capture block DB ₂₁～DB _2nPairing separately maximum gray value VG ₂₁～VG _2nFor instance, if block DB ₂₇Comprise GTG value P21～P24, and GTG value P23＞GTG value P21＞GTG value P22＞GTG value P24.At this moment, gray scale recognition unit 210 will be compared the size of GTG value P21～P24, and therefrom capture GTG value P23 and be used as the pairing maximum gray value of block DB27 VG ₂₇

On the other hand, parameter optimization module 250 can be according to the standard current value I _SpecWith specific current value I _PreRatio and produce an optimization periodic quantity D _Op, standard current value I wherein _SpecLess than specific current value I _PreAfterwards, parameter calculation unit 220 can be according to optimization periodic quantity D _OpWith picture maximum gray value VG _MaxAnd obtain a certain ratio RT2.In addition, parameter calculation unit 220 is more with block DB ₂₁～DB _2nMaximum gray value VG ₂₁～VG _2nMultiply each other with certain ratio RT2 respectively and obtain most working period values D ₂₁～D _2n

For instance, be example with data blocks DB21.At this moment, as the formula (2), parameter calculation unit 220 can be according to optimization periodic quantity D _OpWith picture maximum gray value VG _MaxRatio and obtain certain ratio RT2.Afterwards, as the formula (3), parameter calculation unit 220 can be with maximum gray value VG ₂₁Multiply each other with certain ratio RT2 and obtain working period values D ₂₁

$\mathrm{<figure-callout\; id="2"\; label="RT"\; filenames="H2008102011541E0000021.png"\; state="\{\{state\}\}">RT</figure-callout>}2=\frac{D_{\mathrm{op}}}{{\mathrm{VG}}_{\max }}---\left(2\right)$

D ₂₁=RT2*VG ₂₁(3)

Change, if D _2iIn order to represent i working period values, VG _2iIn order to represent i maximum gray value, n is a positive integer, and i is integer and 1≤i≤n, and then parameter calculation unit 220 is to calculate working period values D according to formula (4) ₂₁～D _2nIn addition, in the present embodiment, if the resolution of image data Data2 is the k position, its pairing picture maximum gray value VG then _MaxBe 2 ^k, k is a positive integer.

D _2i∶D _op＝VG _2i∶VG _max (4)

Afterwards, dimming control unit 230 can be according to working period values D ₂₁～D _2nWith specific current value I _Pre, and produce most brightness adjustment control signal S ₂₁～S _2nBy this, driver element 240 will be according to brightness adjustment control signal S ₂₁～S _2nAnd the required plurality of drive pulse wave PU of generation driven for emitting lights assembly ₂₁～PU _2nIt should be noted that and drive pulse wave PU ₂₁～PU _2nWork period be equal to working period values D respectively ₂₁～D _2nChange speech, light source driving circuit 200 can drive pulse wave PU by adjusting ₂₁～PU _2nWork period reach the mechanism of light modulation.In addition, in the present embodiment, the electric current of described luminescence component is neither greater than specific current value I _Pre

Fig. 2 B illustrates the current waveform figure of the following luminescence component of comparing for Fig. 2 A embodiment and known technology, the current waveform that produced in order to presentation graphs 2A embodiment of label 201 wherein, and label 202 is in order to the expression current waveform that known technology produced.In Fig. 2 A embodiment, because the standard current value I _SpecLess than specific current value I _PreSo shown in current waveform 201, in each display cycle T, light source driving circuit 200 can produce the work periods less than 100% driving pulse wave, causes luminescence component to produce high-high brightness.

And know that the electric current of the luminescence component of flowing through this moment maintains specific current value I _PreAnd greater than the standard current value I _Spec, therefore with known technology compare following, Fig. 2 A embodiment can be under the consumed power that does not promote circuit itself, the high-high brightness of increase luminescence component.Comparatively speaking, adopt the backlight module of present embodiment can utilize less luminescence component to reach the backlight of same brightness, so present embodiment will help to reduce the system cost of backlight module.

Please continue the A with reference to Fig. 2, parameter optimization module 250 comprises energy calculation unit 251 and parameter generating unit 252.Wherein, as the formula (5), energy calculation unit 251 will be in order to will be worth T and standard current value I the display cycle _SpecMultiply each other, and produce a system capacity value P according to this _SysAfterwards, as the formula (6), parameter generating unit 252 can be with system capacity value P _SysDivided by display cycle value T and specific current value I _Pre, and produce optimization periodic quantity D according to this _Op

P _sys＝T×I _spec (5)

$D_{\mathrm{op}}=\frac{P_{\mathrm{sys}}}{T\&times;I_{\mathrm{pre}}}---\left(6\right)$

Change, parameter optimization module 250 mainly is to utilize the standard current value I _SpecWith specific current value I _Pre, produce optimization periodic quantity D _OpWhat deserves to be mentioned is that in the present embodiment, described display cycle value T is inversely proportional to the renewal frequency of image data Data2.

Fig. 3 A illustrates the circuit framework figure into the light source driving circuit of foundation another embodiment of the present invention.With reference to Fig. 3 A, light source driving circuit 300 comprises gray scale recognition unit 310, parameter calculation unit 320, dimming control unit 330, driver element 340 and parameter optimization module 350.Wherein, gray scale recognition unit 310 is electrically connected to parameter calculation unit 320 respectively with parameter optimization module 350.Parameter calculation unit 320 is electrically connected to dimming control unit 330.Dimming control unit 330 then is electrically connected to driver element 340.

In whole start, gray scale recognition unit 310 is in order to be divided into an image data Data3 most data block DB ₃₁～DB _3nAfterwards, gray scale recognition unit 310 can comparison block DB ₃₁～DB _3nIncluded separately GTG value is to capture block DB ₃₁～DB _3nPairing separately maximum gray value VG ₃₁～VG _3nFor instance, if block DB ₃₇Comprise GTG value P31～P34, and GTG value P32＞GTG value P34＞GTG value P33＞GTG value P31.At this moment, gray scale recognition unit 310 will be compared the size of GTG value P31～P34, and therefrom capture GTG value P32 and be used as the pairing maximum gray value of block DB37 VG37.

On the other hand, parameter optimization module 350 can be according to the standard current value I _SpecWith specific period value D _PreRatio and produce an optimization current value I _Op, specific period value D wherein _PreLess than 1.Afterwards, parameter calculation unit 320 can be according to the optimization current value I _OpWith picture maximum gray value VG _MaxAnd obtain a certain ratio RT3.Moreover parameter calculation unit 320 is more with block DB ₃₁～DB _3nMaximum gray value VG ₃₁～VG _3nMultiply each other with certain ratio RT3 respectively and obtain most current value I ₃₁～I _3n

For instance, as the formula (7), parameter calculation unit 320 can be according to the optimization current value I _OpWith picture maximum gray value VG _MaxRatio and obtain certain ratio RT3.Afterwards, as the formula (8), parameter calculation unit 320 can be with maximum gray value VG ₃₁Multiply each other with certain ratio RT3 and obtain current value I ₃₁

$\mathrm{<figure-callout\; id="3"\; label="RT"\; filenames="H2008102011541E0000041.png"\; state="\{\{state\}\}">RT</figure-callout>}3=\frac{I_{\mathrm{op}}}{V{G}_{\max }}---\left(7\right)$

I ₃₁＝RT3*VG ₃₁ (8)

In other words, if I _3iIn order to represent i current value, VG _3iIn order to represent i maximum gray value, n is a positive integer, and i is integer and 1≤i≤n, and then parameter calculation unit 320 is to calculate current value I according to formula (9) ₃₁～I _3nIn addition, in the present embodiment, if the resolution of image data Data3 is the k position, its pairing picture maximum gray value VG then _MaxBe 2 ^k, k is a positive integer.

I _3i∶I _op＝VG _3i∶VG _max (9)

Afterwards, dimming control unit 330 can be according to current value I ₃₁～I _3nWith specific period value D _Pre, and produce most brightness adjustment control signal S ₃₁～S _3nBy this, driver element 340 will be according to brightness adjustment control signal S ₃₁～S _3nAnd the required plurality of drive pulse wave PU of generation driven for emitting lights assembly ₃₁～PU _3nElectric current that it should be noted that described luminescence component is equal to current value I respectively ₃₁～I _3nChange speech, light source driving circuit 300 is to drive pulse wave PU by adjusting ₂₁～PU _2nVoltage quasi position reach the mechanism of light modulation.In addition, in the present embodiment, drive pulse wave PU ₃₁～PU _3nWork period neither greater than specific period value D _Pre

Fig. 3 B illustrates the current waveform figure of the following luminescence component of comparing for Fig. 3 A embodiment and known technology, the current waveform that produced in order to presentation graphs 3A embodiment of label 301 wherein, and label 302 is in order to the expression current waveform that known technology produced.In Fig. 3 A embodiment, shown in current waveform 301, in each display cycle T, light source driving circuit 300 can equal specific period value D the generation work period _PreThe driving pulse wave, cause luminescence component to produce high-high brightness.

In addition, because specific period value D _PreMaintain less than under 1 the situation, so the time the flow through current value I of luminescence component ₃₁Also can be greater than the standard current value I _SpecBy this, with known technology compare following, Fig. 3 A embodiment also can be under the consumed power that does not promote circuit itself, increases the high-high brightness of luminescence component.Comparatively speaking, adopt the backlight module of Fig. 3 A embodiment also can utilize less luminescence component to reach the backlight of same brightness, so Fig. 3 A embodiment also will help to reduce the system cost of backlight module.

In sum, the present invention is to be under the situation of benchmark with the standard current value, utilizes parameter optimization module to produce optimization periodic quantity or optimization current value.By this, the work period of the driving pulse wave that driver element produced is all less than 100%, and the electric current of luminescence component is all greater than the standard current value.Thus, with known technology compare following, the present invention need not promote the consumed power of circuit itself, just can increase the high-high brightness of luminescence component, and and then helps to reduce the system cost of backlight module.

Though the present invention discloses as above with preferred embodiment; right its is not in order to limit the present invention; anyly have the knack of this skill person; 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 as the criterion when looking accompanying the claim person of defining.

Claims (16)

1. a light source driving circuit is characterized in that, in order to driving most luminescence components, and this light source driving circuit comprises:

One gray scale recognition unit in order to an image data being divided into most data blocks, and captures the pairing separately maximum gray value of those block;

One parameter optimization module, in order to produce an optimization periodic quantity according to the ratio of a standard current value and a specific current value, wherein this standard current value is less than this specific current value;

One parameter calculation unit in order to obtaining a certain ratio according to this optimization periodic quantity and a picture maximum gray value, and multiplies each other the maximum gray value of those block respectively and obtains most working period values with this certain ratio;

One dimming control unit in order to according to those working period values and this specific current value, and produces most brightness adjustment control signals; And

One driver element drives the required plurality of drive pulse wave of those luminescence components in order to produce according to those brightness adjustment control signals.

2. light source driving circuit as claimed in claim 1 is characterized in that, wherein this parameter optimization module comprises:

One energy calculation unit in order to a display cycle value and this standard current value are multiplied each other, and produces a system capacity value according to this; And

One parameter generating unit, in order to this system capacity value divided by this value and this specific current value display cycle, and produce this optimization periodic quantity according to this.

3. light source driving circuit as claimed in claim 2 is characterized in that, wherein should be worth the renewal frequency that is inversely proportional to this image data the display cycle.

4. light source driving circuit as claimed in claim 1 is characterized in that, wherein the resolution of this image data is the k position, and this picture maximum gray value is 2 ^k, wherein k is a positive integer.

5. light source driving circuit as claimed in claim 1 is characterized in that, wherein those work periods that drive pulse wave are equal to those working period values respectively.

6. light source driving circuit as claimed in claim 1 is characterized in that, the electric current of those luminescence components of wherein flowing through is neither greater than this specific current value.

7. light source driving circuit as claimed in claim 1 is characterized in that wherein those luminescence components are made of a light emitting diode respectively.

8. light source driving circuit as claimed in claim 1 is characterized in that wherein this light source driving circuit is applicable to a backlight module, and those luminescence components are configured in this backlight module.

9. a light source driving circuit in order to drive a plurality of luminescence components, is characterized in that, this light source driving circuit comprises:

One gray scale recognition unit in order to an image data being divided into most data blocks, and captures the pairing separately maximum gray value of those block;

One parameter optimization module, in order to produce an optimization current value according to the ratio of a standard current value and a specific period value, wherein this specific period value is less than 1;

One parameter calculation unit in order to obtaining a certain ratio according to this optimization current value and a picture maximum gray value, and multiplies each other the maximum gray value of those block respectively and obtains most current values with this certain ratio;

One dimming control unit in order to according to those current values and this specific period value, and produces most brightness adjustment control signals; And

One driver element drives the required plurality of drive pulse wave of those luminescence components in order to produce according to those brightness adjustment control signals.

10. light source driving circuit as claimed in claim 9 is characterized in that, wherein this parameter optimization module comprises:

One energy calculation unit in order to a display cycle value and this standard current value are multiplied each other, and produces a system capacity value according to this; And

One parameter generating unit, in order to this system capacity value divided by this value and this specific period value display cycle, and produce this optimization current value according to this.

11. light source driving circuit as claimed in claim 10 is characterized in that, wherein should be worth the renewal frequency that is inversely proportional to this image data the display cycle.

12. light source driving circuit as claimed in claim 9 is characterized in that, wherein the resolution of this image data is the k position, and this picture maximum gray value is 2 ^k, wherein k is a positive integer.

13. light source driving circuit as claimed in claim 9 is characterized in that, wherein those work periods that drive pulse wave are neither greater than this specific period value.

14. light source driving circuit as claimed in claim 9 is characterized in that, the electric current of those luminescence components of wherein flowing through is equal to those current values respectively.

15. light source driving circuit as claimed in claim 9 is characterized in that, wherein those luminescence components are made of a light emitting diode respectively.

16. light source driving circuit as claimed in claim 9 is characterized in that, wherein this light source driving circuit is applicable to a backlight module, and those luminescence components are configured in this backlight module.

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