CN101521968A - Current regulator and control method thereof - Google Patents
Current regulator and control method thereof Download PDFInfo
- Publication number
- CN101521968A CN101521968A CN200810082444A CN200810082444A CN101521968A CN 101521968 A CN101521968 A CN 101521968A CN 200810082444 A CN200810082444 A CN 200810082444A CN 200810082444 A CN200810082444 A CN 200810082444A CN 101521968 A CN101521968 A CN 101521968A
- Authority
- CN
- China
- Prior art keywords
- current
- voltage
- mirror
- resistance
- regulator
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Landscapes
- Led Devices (AREA)
- Circuit Arrangement For Electric Light Sources In General (AREA)
Abstract
The invention relates to a current regulator and a control method thereof. The current regulator comprises a current source and an intensity controller. The invention has the following characteristics: the current source can provide a driving current which is in direct proportion to ((L plus a) divided by b) n, wherein L is intensity; a, b and n are constants; the intensity controller determines the value of L and is used for generating a current to drive a white LED; and as the relation curve between the current and light-regulating steps is equal to or approximates to the relation curve between the brightness in the human eyes and the intensity, when the light-regulating steps are changed, the human eyes can observe that the brightness of the white LED is linearly changed.
Description
Technical field
The present invention relates to a kind of current regulator, particularly can allow the brightness of white light LEDs change current regulator and the control method thereof that in human eye, is linear change about a kind of in order to the driving white light LEDs.
Background technology
Power consumption is low, the life-span is long, volume is little and low cost and other advantages because light-emitting diode (LED) has, and therefore more and more comes into one's own.Fig. 1 shows known to drive the current regulator 10 of white light LEDs 20, it comprises that current source 12 is in order to provide electric current I REF, the drain of transistor 16 connects the noninverting input of electric current I REF and operational amplifier 14, its source electrode connects earth terminal GND, the output of its gate concatenation operation amplifier 14, the drain of transistor 18 connects the anti-phase input of LED 20 and operational amplifier 14, its source electrode connects earth terminal GND, the output of its gate concatenation operation amplifier 14, transistor 18 mirrors produce DC driven electric current I LED to white light LEDs 20 by the electric current I REF of transistor 16.Fig. 2 shows the relation curve between electric current I REF and the light modulation step (dimming step), because light modulation step and electric current I REF are linear relationship, so can get electric current
IREF=K1 * STEP formula 1
It is characterized in that K1 is a constant, STEP is the exponent number of light modulation step.Fig. 3 shows the relation curve between DC driven electric current I LED and the light modulation step, produces because DC driven electric current I LED is mirror electric current I REF, so also has linear relationship between light modulation step and the DC driven electric current I LED, so the DC driven electric current
ILED=K1 * K2 * STEP formula 2
Wherein, K2 is the ratio of the size of transistor 16 and 18.Fig. 4 shows the luminous intensity (luminous intensity) of white light LEDs 20 and the relation curve between the DC driven electric current I LED, when DC driven electric current I LED increases, in other words the luminous intensity of LED 20, has linear relationship between the brightness of LED 20 and the light modulation step also along with increase.
Though the brightness of white light LEDs 20 is proportional to the light modulation step,, concerning human eye, the brightness that white light LEDs 20 produces is also non-linear.Fig. 5 shows the relation curve 32 between the brightness and shading value in the brightness (luminance) of white light LEDs 20 and relation curve 30 between the shading value (lightness) and the human eye, wherein, actual brightness is represented in the brightness of vertical axis, the brightness that on behalf of human eye, the shading value of trunnion axis perceive, concerning curve 30, the shading value of trunnion axis can be represented the light modulation step.Traditionally, shading value is that 0 interval scale is black entirely, and shading value is that 100 interval scales are white entirely.When the brightness of white light LEDs 20 changes Δ Y, the shading value changes delta L that human eye should be felt, shown in curve 30, in fact, the complex structure of human eye, when brightness is higher, need bigger brightness to change human eye and just can perceive the shading value change, opposite, when brightness is low, the brightness of a little changes the variation that human eye will be experienced shading value, shown in curve 32, therefore, when 1 light modulation step of change makes the brightness of LED 20 change Δ Y, it not is fixed value that the shading value that human eye is perceived changes, and in other words, the light modulation step of current regulator 10 and the shading value that human eye is perceived not are linear relationship.The error amount of brightness between the curve 30 and 32 in Fig. 6 displayed map 5, from it is evident that here, when identical shading value, the required brightness of brightness that LED 20 sends and human eye has very big gap, is near 50 in shading value particularly.
In known current regulator 10, if the shading value that human eye is perceived is linear change, then essential suitable selection light modulation step is when the low current zone, the brightness of LED 20 is as long as change a little, eye-observation to shading value just change, so the light modulation step that can select in low current zone is less, on the contrary, when high galvanic areas, the brightness of LED 20 will have bigger change, and human eye just can be experienced the variation of shading value, so selectable light modulation step is more.Yet,, thereby cause waste no matter be in low current zone or high galvanic areas must have the light modulation step of part not to be used.In addition, choose suitable light modulation step also will be through complicated calculating, and this also increases the difficulty in the design.
Therefore known current regulator exists above-mentioned all inconvenience and problem.
Summary of the invention
Purpose of the present invention is to propose a kind ofly can make the brightness of white light LEDs change current regulator and the control method thereof that is linear change in human eye.
Another object of the present invention is to propose a kind ofly can make the brightness of white light LEDs change current regulator and the control method thereof that is almost linear change in human eye.
For achieving the above object, technical solution of the present invention is:
A kind of current regulator comprises a current source and a shading value controller, it is characterized in that:
Described current source provide and one be proportional to (drive current of (L+a)/b) n, wherein L is a shading value, a, b and n are constant;
The value of described shading value controller decision L.
Current regulator of the present invention can also be further achieved by the following technical measures.
Aforesaid current regulator, wherein said constant a is 16, and constant b is 116, and constant n is 3.
Aforesaid current regulator, wherein said current source comprises:
One first functional circuit, generation is proportional to the (electric current of (L+a)/b) according to an input signal; And
One second functional circuit produces according to the output of described first functional circuit and to be proportional to (the electric current of (L+a)/b) 2.
Aforesaid current regulator, wherein said current source more comprise one the 3rd functional circuit, produce according to the output of described second functional circuit and are proportional to (the electric current of (L+a)/b) 3.
Aforesaid current regulator, wherein said current source also comprises:
One first resistance, its resistance value has proportionate relationship with ((L+16)/116);
One second resistance, its resistance value has proportionate relationship with ((L+16)/116);
One the 3rd resistance, its resistance value has proportionate relationship with ((L+16)/116);
One second current source is supplied described first electric current to the first resistance to produce one first voltage
One first voltage current adapter is in order to being one second electric current with described first voltage transitions;
One first current mirror, described second electric current of mirror produce one the 3rd electric current to the second resistance to produce one second voltage;
One second voltage current adapter is in order to being one the 4th electric current with described second voltage transitions;
One second current mirror, described the 4th electric current of mirror produce one the 5th electric current to the, three resistance to produce a tertiary voltage;
One tertiary voltage current converter is in order to be converted to described tertiary voltage in one the 6th electric current; And
One the 3rd current mirror, described the 6th electric current of mirror produces drive current.
Aforesaid current regulator, wherein said first, second and third resistance has same resistance value.
Aforesaid current regulator, wherein said current source also comprises:
One current mirror, mirror one reference current produces described drive current;
One voltage current adapter is converted to reference current with a reference voltage; And
One switch, be controlled by a control signal, in order to control the ON time of described reference current, described control signal comprises that a primary period has the work period than being ((L+16)/116), in the operating time in described primary period, comprise one first subcycle and have the work period, in the operating time of described first subcycle, comprise one second subcycle and have the work period than being ((L+16)/116) than being ((L+16)/116).
Aforesaid current regulator, wherein said current source more comprises:
One first resistance, its resistance value has proportionate relationship with ((L+16)/116);
One second resistance, its resistance value has proportionate relationship with ((L+16)/116);
One second current source, supply one first electric current to described first resistance to produce one first voltage;
One first voltage current adapter is in order to being one second electric current with described first voltage transitions;
One first current mirror, described second electric current of mirror produce one the 3rd electric current to the second resistance to produce one second voltage;
One second voltage current adapter is in order to being one the 4th electric current with described second voltage transitions;
One second current mirror, described the 4th electric current of mirror produces drive current;
One switch is controlled by a control signal, and in order to control the ON time of described the 4th electric current, described control signal has the work period than being ((L+16)/116).
Aforesaid current regulator, wherein said first and second resistance has same resistance value.
Aforesaid current regulator comprises more that wherein a low pressure spill current source produces an output current according to described drive current and gives light-emitting diode.
Aforesaid current regulator, wherein said low pressure spill current source comprises:
One operational amplifier has one first input, one second input and an output;
One the first transistor has that a drain connects described drive current and first input, one source pole connects a reference voltage and a gate and connects output;
One transistor seconds has that a drain connects described light-emitting diode and second input, one source pole connects described reference voltage and a gate and connects output, produces described output current in order to the described drive current of mirror by described the first transistor.
Aforesaid current regulator, the relation curve between wherein said drive current and the shading value approach the relation curve between the brightness and shading value in the human eye.
Aforesaid current regulator, wherein said current source provides a drive current with the light modulation step change, second relation curve in the approximate human eye of first relation curve between described drive current and the described light modulation step between brightness and the shading value; And
Described output circuit produces an output current according to described drive current and gives light-emitting diode.
Aforesaid current regulator, wherein said output circuit comprise that the described drive current of one second current source mirror produces described output current.
Aforesaid current regulator, wherein said current source also comprises:
One current mirror produces drive current in order to mirror one reference current;
One variable resistor, its resistance value is determined by described light modulation step;
One transistor is connected between described variable resistor and the described current mirror; And
One operational amplifier, have two inputs and connect variable voltage and a described variable resistor and the described transistorized gate of an output connection with described light modulation step change respectively, operational amplifier offers described variable resistor to produce reference current with described variable voltage.
Aforesaid current regulator, wherein said variable-resistance resistance value are 2 curtain power.
Aforesaid current regulator, wherein said current source also comprises:
One current mirror, mirror one reference current produces drive current;
One voltage current adapter is converted to reference current with a reference voltage; And
One switch is controlled by a control signal, and in order to control the ON time of described reference current, the operating time of described control signal and described reference voltage are all by described light modulation step decision.
Aforesaid current regulator, the wherein said operating time is 2 curtain power.
Aforesaid current regulator, wherein said second current source comprises:
One operational amplifier has one first input, one second input and an output;
One the first transistor, have a drain connect described drive current and first the input, one source pole connects a reference voltage and a gate connects described output;
One transistor seconds has that a drain connects the described light-emitting diode and second input, one source pole connects described reference voltage and a gate connects described output, produces described output current in order to the described drive current of mirror by described the first transistor.
Aforesaid current regulator, the error amount of wherein said first relation curve and described second relation curve is lower than 10%.
Aforesaid current regulator, wherein said second relation curve are Y/Yn=((L+16)/116) 3, it is characterized in that, Y is brightness, the brightness when Yn is white entirely, and L is a shading value.
A kind of control method of current regulator comprises the following steps:
First step: provide a drive current with the light modulation step change, second relation curve in the approximate human eye of first relation curve between described drive current and the described light modulation step between brightness and the shading value; And
Second step: produce an output current according to described drive current and give light-emitting diode.
The control method of aforesaid current regulator, wherein said second step comprise that the described drive current of mirror produces output current.
The control method of aforesaid current regulator, wherein said first step comprises:
Provide variable resistor that a variable voltage to that changes with described light modulation step changes with described light modulation step to produce a reference current; And
Mirror one reference current produces drive current.
The control method of aforesaid current regulator, wherein said variable-resistance resistance value are 2 curtain power.
The control method of aforesaid current regulator, wherein said first step also comprises:
One reference voltage is converted to a reference current;
The described reference current of mirror produces drive current; And
Control the ON time of described reference current;
The ON time of described reference current and described reference voltage are all by described light modulation step decision.
The control method of aforesaid current regulator, the ON time of wherein said reference current are 2 curtain power.
The control method of aforesaid current regulator, the error amount of wherein said first relation curve and described second relation curve is lower than 10%.
The control method of aforesaid current regulator, wherein said second relation curve are Y/Yn=((L+16)/116) 3, and wherein Y is brightness, the brightness when Yn is white entirely, and L is a shading value.
After adopting technique scheme, current regulator of the present invention has the following advantages:
(1). can make the brightness variation of white light LEDs in human eye, be linear change.
(2). can make the brightness variation of white light LEDs in human eye, be almost linear change.
Description of drawings
Fig. 1 shows known to drive the current regulator of white light LEDs;
Relation curve in Fig. 2 displayed map 1 between electric current I REF and the light modulation step;
Relation curve in Fig. 3 displayed map 1 between DC driven electric current I LED and the light modulation step;
Fig. 4 shows the luminous intensity of white light LEDs and the relation curve between the DC driven electric current I LED;
Fig. 5 shows the relation curve between the brightness and shading value in the brightness of white light LEDs 20 and relation curve between the shading value and the human eye;
The error amount of brightness between the curve 30 and 32 in Fig. 6 displayed map 5;
Fig. 7 is the first embodiment of the present invention;
The relation curve of the electric current of current source 42 and light modulation step in Fig. 8 displayed map 7;
Fig. 9 shows the relation curve of electric current I LED and light modulation step;
The brightness of LED 48 and the relation curve between the shading value and brightness in the human eye and the relation curve between the shading value in Figure 10 displayed map 7;
Figure 11 is the second embodiment of the present invention;
The embodiment of Figure 12 display control signal PWM;
Figure 13 is the third embodiment of the present invention;
Figure 14 shows the embodiment of control signal PWM among Figure 13;
Figure 15 is the fourth embodiment of the present invention;
Figure 16 shows in the human eye brightness of LED 48 and the relation curve between the shading value in the relation curve between the brightness and shading value and current regulator 70;
Figure 17 shows the error amount between two curves 74 and 76 among Figure 16;
Figure 18 is the fifth embodiment of the present invention;
Figure 19 shows in the human eye brightness of LED 48 and the relation curve between the shading value in the relation curve between the brightness and shading value and current regulator 80; And
Figure 20 shows the error amount between two curves 84 and 86 among Figure 19.
Embodiment
Below in conjunction with embodiment and accompanying drawing thereof the present invention is illustrated further.
In known document, the change type between brightness Y and the shading value L
L=116f (Y/Yn)-16 formula 1
Brightness when wherein, Yn is white entirely.At (Y/Yn)〉0.008856 o'clock f (Y/Yn)=(Y/Yn) 1/3, otherwise f (Y/Yn)=7.787 (Y/Yn)+16/116.Can push away by formula 1
F (Y/Yn)=((L+16)/116) formula 2
Ignore because scope (Y/Yn)＜0.008856 is very little, therefore can further push away
(Y/Yn)=((L+16)/116) 3 formula 3
Therefore, as long as the brightness coincidence formula 3 that light-emitting diode sent just can meet the shading value variation that human eye is perceived.More detailed content please refer to webpage http://en.wikipedia.org/wiki/Lab_color_space.
At first see also Fig. 7, Fig. 7 is first embodiment of the present invention figure.As shown in the figure, in described current regulator 40, current source 42 provides drive current IREF=K1 * ((L+16)/116) 3, wherein K1 is a constant, shading value controller 44 is in order to the value of decision shading value L, at this shading value L is the light modulation step, low pressure reduction (low dropout) current source 46 produces output current ILED according to electric current I REF and gives LED 48, low pressure spill current source comprises operational amplifier 4602 and transistor 4604 and 4606, wherein, transistor 4604 is connected between electric current I LED and the earth terminal GND, transistor 4606 is connected between LED 48 and the earth terminal GND, the noninverting input of operational amplifier 4602 and anti-phase input connect the drain of transistor 4604 and 4606 respectively, and the output of operational amplifier 4602 connects the gate of transistor 4604 and 4606.
Fig. 8 shows the relation curve of electric current and light modulation step in the current source 42.In current source 42, variable resistor 4204,4210 and 4216 have identical resistance value ((L+16)/116) * R, current source 4202 provide electric current I 1 to variable resistor 4204 to produce voltage V1=((L+16)/116) * R * I1, voltage current adapter 4206 is converted to electric current I 2=((L+16)/116) * I1 with voltage V1, current mirror 4208 mirror electric current I 2 produce electric current I 3=((L+16)/116) * I1 * n1 and give resistance 4210 to produce voltage V2=((L+16)/116) 2 * R * I1 * n1, the curve of electric current I 3 is shown in the curve 50 of Fig. 8, voltage current adapter 4212 is converted to electric current I 4=((L+16)/116) 2 * I1 * n1 with voltage V2, current mirror 4214 mirror electric current I 4 produce electric current I 5=((L+16)/116) 2 * I1 * n1 * n2 and give resistance 4216 to produce voltage V3=((L+16)/116) 3 * R * I1 * n1 * n2, the curve of electric current I 5 is shown in the curve 52 of Fig. 8, voltage current adapter 4218 is converted to electric current I 6=((L+16)/116) 3 * I1 * n1 * n2 with voltage V3, current mirror 4220 mirror electric current I 6 produce electric current I REF=K1 * ((L+16)/116) 3, shown in the curve 54 of Fig. 8, at this K1=I1 * n1 * n2 * n3.
Fig. 9 shows the relation curve of electric current I LED and light modulation step.In low pressure spill current source 46, operational amplifier 4602 makes the voltage between the transistor 4604 lock drains equal the voltage between the transistor 4606 lock drains, so transistor 4606 is with the electric current I REF of mirror by transistor 4604, suppose that the size ratio between transistor 4604 and 4606 is 1:K2, then can get electric current I LED=K1 * K2 * ((L+16)/116) 3, as shown in Figure 9.Relation curve between brightness and the shading value in the brightness of LED48 and relation curve between the shading value and the human eye in Figure 10 displayed map 7, wherein, article two, curves overlapped, therefore, 1 light modulation step of every change L, the shading value that human eye is discovered is changed to definite value, so the light modulation step of current regulator 40 and the shading value that human eye is perceived have linear relationship, so need not to choose suitable light modulation step via the calculating of complexity again and makes the brightness of the LED of eye-observation be changed to linearity, there is not the light modulation step by idle and cause waste yet.
Figure 11 is the second embodiment of the present invention, described current regulator 60 comprises current source 62, shading value controller 64 and low pressure spill current source 46, current source 62 provides electric current I REF=K1 * ((L+16)/116) 3, shown in the curve 54 of Fig. 8, shading value controller 64 is in order to the value of decision shading value L, at this shading value L is the light modulation step, and low pressure spill current source 46 produces electric current I LED according to electric current I REF, as shown in Figure 9.In current source 62, voltage current adapter 6202 is converted to electric current I 1 with voltage VREF, pwm signal generator 6204 switches the switch S 1 that is connected between voltage current adapter 6202 and the earth terminal GND according to the output L generation control signal PWM of shading value controller 64, the ON time of Control current I1 thus, current mirror 6206 mirror electric current I 1 produce electric current I REF.The embodiment of Figure 12 display control signal PWM, wherein, control signal PWM comprises that primary period T1 has the work period than ((L+16)/116), and comprising the first subcycle T2, the operating time of primary period T1 has the work period than ((L+16)/116), the operating time of the first subcycle T2 comprises second subcycle again and has ((L+16)/116), therefore, can learn that the average current of electric current I REF equals K1 * ((L+16)/116) 3, at this K1=I1.Because electric current I REF is proportional to ((L+16)/116) 3, so electric current I LED also is proportional to ((L+16)/116) 3, in other words, relation curve in the brightness of LED 48 among Figure 11 and relation curve between the shading value and the human eye between brightness and the shading value is overlapping, as shown in figure 10, so the light modulation step of current regulator 60 and shading value that human eye is perceived have linear relationship.
Figure 13 is the third embodiment of the present invention, described current regulator 66 comprises current source 68, shading value controller 69 and low pressure spill current source 46, current source 68 provides electric current I REF=K1 * ((L+16)/116) 3, shown in the curve 54 of Fig. 8, shading value controller 69 is in order to the value of decision shading value L, at this shading value L is the light modulation step, and low pressure spill current source 46 produces electric current I LED according to electric current I REF.In current source 68, variable resistor 6804 and 6810 has identical resistance value ((L+16)/116) * R, current source 6802 provide electric current I 1 to variable resistor 6804 to produce voltage V1=((L+16)/116) * R * I1, voltage current adapter 6806 is converted to electric current I 2=((L+16)/116) * I1 with voltage V1, current mirror 6808 mirror electric current I 2 produce electric current I 3=((L+16)/116) * I1 * n1 and give resistance 6810 to produce voltage V2=((L+16)/116) 2 * R * I1 * n1, voltage current adapter 6812 is converted to electric current I 4=((L+16)/116) 2 * I1 * n1 with voltage V2, switch S 1 is connected between voltage current adapter 6812 and the earth terminal GND, pwm signal generator 6816 produces control signal PWM diverter switch S1 according to the output L of shading value controller 69, Figure 14 shows the embodiment of control signal PWM among Figure 13, it comprises that period T 1 has the work period than ((L+16)/116), it produces electric current I REF with reference to the electric current in the branch current mirror 6814 mirrors, because the work period of control signal PWM is than being ((L+16)/116), so can learn that the average current of electric current I REF equals I4 * n2 * ((L+16)/116), electric current I 4 equals ((L+16)/116) 2 * I1 * n1 again, so the average current of electric current I REF equals K1 * ((L+16)/116) 3, at this K1=I1 * n1 * n2.
Figure 15 is the fourth embodiment of the present invention, described current regulator 70 comprises that current source 72 provides electric current I REF and low pressure spill current source 46 to produce electric current I LED to LED48 according to electric current I REF, and this embodiment utilizes the mode of fragment linear approximation (piecewise linear approach) to obtain the curve of approximate formula 3.In current source 72, voltage current adapter 7201 is converted to electric current I 1 with variable voltage V1=(N/40) * VREF, current mirror 7206 mirror electric current I 1 produce electric current I REF, in voltage current adapter 7201, operational amplifier 7202 has noninverting input and anti-phase input connects variable voltage V1 and node A respectively, in order to voltage V1 is provided to node A, wherein, N is the light modulation step, in this embodiment, N equals 21～40, a plurality of resistance R with same resistance value are connected in parallel between node A and the earth terminal GND to form equivalent resistance 7204, a plurality of switch S 1～S16 connect with a resistance separately, and diverter switch S1～S16 can change the resistance value of equivalent resistance 7204 thus, and equivalent resistance 7204 produces electric current I 1 in response to voltage V1.Figure 16 shows in the human eye brightness and the relation curve between the shading value 76 of LED48 in the relation curve 74 between the brightness and shading value and current regulator 70.With reference to Figure 15 and 16, in this embodiment, it is 5 sections that curve 76 is divided into, and the exponent number of light modulation step N totally 20 rank, so every section comprises 4 light modulation steps, in each section, the resistance value of equivalent resistance 7204 all will change to change the slope of electric current I LED, as shown in figure 16, in the 1st section, switch S 1 is opened (turn on), and all the other close (turn off), and the resistance value of equivalent resistance 7204 is R, in the 2nd section, switch S 1 and S2 open and all the other are closed, and the resistance value of equivalent resistance 7204 becomes R/2, in the 3rd section, switch S 1～S4 opens and all the other are closed, so the resistance value of equivalent resistance 7204 is R/4, in the 4th section, switch S 1～S8 opens and all the other are closed, so the resistance value of equivalent resistance 7204 is R/8, in the 5th section, switch S 1～S16 opens entirely, so the resistance value of equivalent resistance 7204 is R/16, clearly, the resistance value of equivalent resistance 7204 is 2 curtain power.In other embodiments, as long as suitable exponent number and the resistance R of choosing reference voltage VREF, light modulation step, the hop count of the curve 76 of electric current I LED is to change, and along with the increase of hop count, the curve 76 of electric current I LED can be more near curve 74.Figure 17 shows the error amount between two curves 74 and 76 among Figure 16, and wherein, the error amount between two curves 74 and 76 is no more than 10%, obvious two curves 74 and 76 quite approximate, so when light modulation step N changes, the brightness of LED 48 change in human eye, be close to linear.
Figure 18 is the fifth embodiment of the present invention, described current regulator 80 comprises that current source 82 provides electric current I REF and low pressure spill current source 46 to produce electric current I LED to LED48 according to electric current I REF, and this embodiment utilizes the mode of fragment linear approximation to obtain the curve of approximate formula 3 equally.In current source 82, voltage current adapter 8202 is converted to electric current I 1 with variable voltage V1=(N/40) * VREF, switch S 1 is connected between voltage current adapter 8202 and the earth terminal GND, be controlled by control signal PWM, in order to the ON time of Control current I1, current mirror 8204 mirror electric current I 1 produce electric current I REF.Figure 19 show in the human eye brightness of LED 48 and shading value in the relation curve 84 between the brightness and shading value and current regulator 80 relation curve 86.With reference to Figure 18 and 19, in this embodiment, the curve 86 of electric current I LED is divided into 5 sections equally, and the exponent number of light modulation step N totally 20 rank, so every section comprises 4 light modulation steps, in each section, control signal PWM has the different operating times, the work period of the control signal PWM of each section ratio is respectively (1/16), (2/16), (4/16), (8/16) and (16/16) as seen from Figure 19, the operating time of control signal PWM is 2 curtain power, when the operating time of control signal PWM increased, the slope of curve 86 also and then increased.In other embodiments, as long as suitable exponent number and the resistance R of choosing reference voltage VREF, light modulation step, the hop count of the curve 86 of electric current I LED is to change, and along with the increase of hop count, the curve 86 of electric current I LED can be more near curve 84.Figure 20 shows the error amount between two curves 84 and 86 among Figure 19, and wherein, the error amount between two curves 84 and 86 is no more than 10%, obvious two curves 84 and 86 quite approximate, so when light modulation step N changes, the brightness of LED48 change in human eye, be close to linear.
Above embodiment is only for the usefulness that the present invention is described, but not limitation of the present invention, person skilled in the relevant technique under the situation that does not break away from the spirit and scope of the present invention, can also be made various conversion or variation.Therefore, all technical schemes that are equal to also should belong to category of the present invention, should be limited by each claim.
Claims (29)
1. a current regulator comprises a current source and a shading value controller, it is characterized in that:
Described current source provide and one be proportional to (drive current of (L+a)/b) n, wherein L is a shading value, a, b and n are constant;
The value of described shading value controller decision L.
2. current regulator as claimed in claim 1 is characterized in that, described constant a is 16, and constant b is 116, and constant n is 3.
3. current regulator as claimed in claim 1 is characterized in that, described current source comprises:
One first functional circuit, generation is proportional to the (electric current of (L+a)/b) according to an input signal; And
One second functional circuit produces according to the output of described first functional circuit and to be proportional to (the electric current of (L+a)/b) 2.
4. current regulator as claimed in claim 3 is characterized in that, described current source more comprises one the 3rd functional circuit, produces according to the output of described second functional circuit and is proportional to (the electric current of (L+a)/b) 3.
5. current regulator as claimed in claim 1 is characterized in that, described current source also comprises:
One first resistance, its resistance value has proportionate relationship with ((L+16)/116);
One second resistance, its resistance value has proportionate relationship with ((L+16)/116);
One the 3rd resistance, its resistance value has proportionate relationship with ((L+16)/116);
One second current source is supplied described first electric current to the first resistance to produce one first voltage
One first voltage current adapter is in order to being one second electric current with described first voltage transitions;
One first current mirror, described second electric current of mirror produce one the 3rd electric current to the second resistance to produce one second voltage;
One second voltage current adapter is in order to being one the 4th electric current with described second voltage transitions;
One second current mirror, described the 4th electric current of mirror produce one the 5th electric current to the, three resistance to produce a tertiary voltage;
One tertiary voltage current converter is in order to be converted to described tertiary voltage in one the 6th electric current; And
One the 3rd current mirror, described the 6th electric current of mirror produces drive current.
6. current regulator as claimed in claim 5 is characterized in that, described first, second and third resistance has same resistance value.
7. current regulator as claimed in claim 1 is characterized in that, described current source also comprises:
One current mirror, mirror one reference current produces described drive current;
One voltage current adapter is converted to reference current with a reference voltage; And
One switch, be controlled by a control signal, in order to control the ON time of described reference current, described control signal comprises that a primary period has the work period than being ((L+16)/116), in the operating time in described primary period, comprise one first subcycle and have the work period, in the operating time of described first subcycle, comprise one second subcycle and have the work period than being ((L+16)/116) than being ((L+16)/116).
8. current regulator as claimed in claim 1 is characterized in that, described current source more comprises:
One first resistance, its resistance value has proportionate relationship with ((L+16)/116);
One second resistance, its resistance value has proportionate relationship with ((L+16)/116);
One second current source, supply one first electric current to described first resistance to produce one first voltage;
One first voltage current adapter is in order to being one second electric current with described first voltage transitions;
One first current mirror, described second electric current of mirror produce one the 3rd electric current to the second resistance to produce one second voltage;
One second voltage current adapter is in order to being one the 4th electric current with described second voltage transitions;
One second current mirror, described the 4th electric current of mirror produces drive current;
One switch is controlled by a control signal, in order to control the ON time of described the 4th electric current, institute
State control signal and have the work period than being ((L+16)/116).
9. current regulator as claimed in claim 8 is characterized in that, described first and second resistance has same resistance value.
10. current regulator as claimed in claim 1 comprises that more a low pressure spill current source produces an output current according to described drive current and gives light-emitting diode.
11. current regulator as claimed in claim 10 is characterized in that, described low pressure spill current source comprises:
One operational amplifier has one first input, one second input and an output;
One the first transistor has that a drain connects described drive current and first input, one source pole connects a reference voltage and a gate and connects output;
One transistor seconds has that a drain connects described light-emitting diode and second input, one source pole connects described reference voltage and a gate and connects output, produces described output current in order to the described drive current of mirror by described the first transistor.
12. current regulator as claimed in claim 1 is characterized in that, the relation curve between described drive current and the shading value approaches the relation curve between the brightness and shading value in the human eye.
13. a current regulator comprises a current source and an output circuit, it is characterized in that:
Described current source provides a drive current with the light modulation step change, second relation curve in the approximate human eye of first relation curve between described drive current and the described light modulation step between brightness and the shading value; And
Described output circuit produces an output current according to described drive current and gives light-emitting diode.
14. current regulator as claimed in claim 13 is characterized in that, described output circuit comprises that the described drive current of one second current source mirror produces described output current.
15. current regulator as claimed in claim 13 is characterized in that, described current source also comprises:
One current mirror produces drive current in order to mirror one reference current;
One variable resistor, its resistance value is determined by described light modulation step;
One transistor is connected between described variable resistor and the described current mirror; And
One operational amplifier, have two inputs and connect variable voltage and a described variable resistor and the described transistorized gate of an output connection with described light modulation step change respectively, operational amplifier offers described variable resistor to produce reference current with described variable voltage.
16. current regulator as claimed in claim 15 is characterized in that, described variable-resistance resistance value is 2 curtain power.
17. current regulator as claimed in claim 13 is characterized in that, described current source also comprises:
One current mirror, mirror one reference current produces drive current;
One voltage current adapter is converted to reference current with a reference voltage; And
One switch is controlled by a control signal, and in order to control the ON time of described reference current, the operating time of described control signal and described reference voltage are all by described light modulation step decision.
18. current regulator as claimed in claim 17 is characterized in that, the described operating time is 2 curtain power.
19. current regulator as claimed in claim 14 is characterized in that, described second current source comprises:
One operational amplifier has one first input, one second input and an output;
One the first transistor, have a drain connect described drive current and first the input, one source pole connects a reference voltage and a gate connects described output;
One transistor seconds has that a drain connects the described light-emitting diode and second input, one source pole connects described reference voltage and a gate connects described output, produces described output current in order to the described drive current of mirror by described the first transistor.
20. current regulator as claimed in claim 13 is characterized in that, the error amount of described first relation curve and described second relation curve is lower than 10%.
21. current regulator as claimed in claim 13 is characterized in that, described second relation curve is Y/Yn=((L+16)/116) 3, it is characterized in that, Y is brightness, the brightness when Yn is white entirely, and L is a shading value.
22. a control method of controlling claim 1 or 13 described current regulators is characterized in that, comprises the following steps:
First step: provide a drive current with the light modulation step change, second relation curve in the approximate human eye of first relation curve between described drive current and the described light modulation step between brightness and the shading value; And
Second step: produce an output current according to described drive current and give light-emitting diode.
23. control method as claimed in claim 22 is characterized in that, described second step comprises that the described drive current of mirror produces output current.
24. control method as claimed in claim 22 is characterized in that, described first step comprises:
Provide variable resistor that a variable voltage to that changes with described light modulation step changes with described light modulation step to produce a reference current; And
Mirror one reference current produces drive current.
25. control method as claimed in claim 24 is characterized in that, described variable-resistance resistance value is 2 curtain power.
26. control method as claimed in claim 22 is characterized in that, described first step also comprises:
One reference voltage is converted to a reference current;
The described reference current of mirror produces drive current; And
Control the ON time of described reference current;
The ON time of described reference current and described reference voltage are all by described light modulation step decision.
27. control method as claimed in claim 26 is characterized in that, the ON time of described reference current is 2 curtain power.
28. control method as claimed in claim 22 is characterized in that, the error amount of described first relation curve and described second relation curve is lower than 10%.
29. control method as claimed in claim 22 is characterized in that, described second relation curve is Y/Yn=((L+16)/116) 3, and wherein Y is brightness, the brightness when Yn is white entirely, and L is a shading value.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200810082444.9A CN101521968B (en) | 2008-02-27 | 2008-02-27 | Current regulator and control method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200810082444.9A CN101521968B (en) | 2008-02-27 | 2008-02-27 | Current regulator and control method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101521968A true CN101521968A (en) | 2009-09-02 |
| CN101521968B CN101521968B (en) | 2014-03-19 |
Family
ID=41082274
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN200810082444.9A Expired - Fee Related CN101521968B (en) | 2008-02-27 | 2008-02-27 | Current regulator and control method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN101521968B (en) |
Cited By (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101965083A (en) * | 2010-08-27 | 2011-02-02 | 深圳市佳比泰电子科技有限公司 | Dimmer remote switch control device applied to light-emitting diode (LED) and using method thereof |
| CN102065596A (en) * | 2009-11-12 | 2011-05-18 | 冠捷投资有限公司 | Driving device for light emitting diode backlight |
| CN102438367A (en) * | 2011-10-25 | 2012-05-02 | 复旦大学 | Linear dimming system based on brightness perceived by human eyes |
| CN102566643A (en) * | 2010-12-30 | 2012-07-11 | 鸿富锦精密工业（深圳）有限公司 | Driving voltage adjustment circuit |
| CN102622957A (en) * | 2011-02-01 | 2012-08-01 | 北京大学 | Multichannel LED constant current source driving circuit based on MOSFET of linear region with constant grid voltage |
| CN102681591A (en) * | 2011-01-27 | 2012-09-19 | 美士美积体产品公司 | Current mirror and current cancellation circuit |
| CN103955254A (en) * | 2014-03-18 | 2014-07-30 | 尚睿微电子（上海）有限公司 | Circuit capable of generating multiple current references |
| CN103974499A (en) * | 2013-02-01 | 2014-08-06 | 立锜科技股份有限公司 | Linear dimming circuit and method for light emitting component |
| CN105591557A (en) * | 2014-11-07 | 2016-05-18 | 电力集成公司 | Power Converter Controller With Input Current Slope Adjustment |
| CN106708165A (en) * | 2017-03-15 | 2017-05-24 | 深圳慧能泰半导体科技有限公司 | Current source circuit, chip and electronic equipment |
| CN107918439A (en) * | 2017-11-08 | 2018-04-17 | 西安电子科技大学昆山创新研究院 | APD dark current compensations analog front circuit and APD dark current compensation methods |
| CN109451622A (en) * | 2018-09-27 | 2019-03-08 | 天津华来科技有限公司 | A kind of control method of LED illumination lamp brightness change, apparatus and system |
| CN110568891A (en) * | 2019-09-24 | 2019-12-13 | 上海艾为电子技术股份有限公司 | current DAC circuit and current output method |
| CN117082673A (en) * | 2023-10-16 | 2023-11-17 | 无锡英迪芯微电子科技股份有限公司 | Method and device for controlling brightness of light-emitting device and light-emitting module |
| CN117528858A (en) * | 2024-01-08 | 2024-02-06 | 杭州罗莱迪思科技股份有限公司 | Hidden-lighting controllable dimming lamp control method |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112055454B (en) * | 2020-08-31 | 2022-09-13 | 惠州市西顿工业发展有限公司 | Method for establishing dimming curve look-up table, dimming method and dimmer |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1627343A (en) * | 2003-12-08 | 2005-06-15 | 戴洛格半导体公司 | Light show ASIC |
| US20060022915A1 (en) * | 2004-07-29 | 2006-02-02 | Sebastien Weitbruch | Method and apparatus for power level control and/or contrast control in a display device |
| CN101074762A (en) * | 2006-05-15 | 2007-11-21 | 比亚迪股份有限公司 | Image sensor testing light source system |
-
2008
- 2008-02-27 CN CN200810082444.9A patent/CN101521968B/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1627343A (en) * | 2003-12-08 | 2005-06-15 | 戴洛格半导体公司 | Light show ASIC |
| US20060022915A1 (en) * | 2004-07-29 | 2006-02-02 | Sebastien Weitbruch | Method and apparatus for power level control and/or contrast control in a display device |
| CN101074762A (en) * | 2006-05-15 | 2007-11-21 | 比亚迪股份有限公司 | Image sensor testing light source system |
Cited By (22)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102065596A (en) * | 2009-11-12 | 2011-05-18 | 冠捷投资有限公司 | Driving device for light emitting diode backlight |
| CN101965083A (en) * | 2010-08-27 | 2011-02-02 | 深圳市佳比泰电子科技有限公司 | Dimmer remote switch control device applied to light-emitting diode (LED) and using method thereof |
| CN102566643B (en) * | 2010-12-30 | 2015-04-01 | 项敬来 | Driving voltage adjustment circuit |
| CN102566643A (en) * | 2010-12-30 | 2012-07-11 | 鸿富锦精密工业（深圳）有限公司 | Driving voltage adjustment circuit |
| CN102681591A (en) * | 2011-01-27 | 2012-09-19 | 美士美积体产品公司 | Current mirror and current cancellation circuit |
| CN102622957B (en) * | 2011-02-01 | 2014-07-02 | 北京大学 | Multichannel LED constant current source driving circuit based on MOSFET of linear region with constant grid voltage |
| CN102622957A (en) * | 2011-02-01 | 2012-08-01 | 北京大学 | Multichannel LED constant current source driving circuit based on MOSFET of linear region with constant grid voltage |
| CN102438367B (en) * | 2011-10-25 | 2014-04-02 | 复旦大学 | Linear dimming system based on brightness perceived by human eyes |
| CN102438367A (en) * | 2011-10-25 | 2012-05-02 | 复旦大学 | Linear dimming system based on brightness perceived by human eyes |
| CN103974499A (en) * | 2013-02-01 | 2014-08-06 | 立锜科技股份有限公司 | Linear dimming circuit and method for light emitting component |
| CN103955254A (en) * | 2014-03-18 | 2014-07-30 | 尚睿微电子（上海）有限公司 | Circuit capable of generating multiple current references |
| CN103955254B (en) * | 2014-03-18 | 2015-11-11 | 尚睿微电子（上海）有限公司 | A kind of circuit producing multiple current reference |
| CN105591557B (en) * | 2014-11-07 | 2019-03-08 | 电力集成公司 | Power converter controller with the adjustment of input current slope |
| CN105591557A (en) * | 2014-11-07 | 2016-05-18 | 电力集成公司 | Power Converter Controller With Input Current Slope Adjustment |
| CN106708165A (en) * | 2017-03-15 | 2017-05-24 | 深圳慧能泰半导体科技有限公司 | Current source circuit, chip and electronic equipment |
| CN107918439A (en) * | 2017-11-08 | 2018-04-17 | 西安电子科技大学昆山创新研究院 | APD dark current compensations analog front circuit and APD dark current compensation methods |
| CN109451622A (en) * | 2018-09-27 | 2019-03-08 | 天津华来科技有限公司 | A kind of control method of LED illumination lamp brightness change, apparatus and system |
| CN110568891A (en) * | 2019-09-24 | 2019-12-13 | 上海艾为电子技术股份有限公司 | current DAC circuit and current output method |
| CN117082673A (en) * | 2023-10-16 | 2023-11-17 | 无锡英迪芯微电子科技股份有限公司 | Method and device for controlling brightness of light-emitting device and light-emitting module |
| CN117082673B (en) * | 2023-10-16 | 2024-01-26 | 无锡英迪芯微电子科技股份有限公司 | Method and device for controlling brightness of light-emitting device and light-emitting module |
| CN117528858A (en) * | 2024-01-08 | 2024-02-06 | 杭州罗莱迪思科技股份有限公司 | Hidden-lighting controllable dimming lamp control method |
| CN117528858B (en) * | 2024-01-08 | 2024-04-09 | 杭州罗莱迪思科技股份有限公司 | Hidden-lighting controllable dimming lamp control method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN101521968B (en) | 2014-03-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101521968B (en) | Current regulator and control method thereof | |
| TWI455646B (en) | Current regulator and its control method | |
| KR100898209B1 (en) | LED drive circuit | |
| KR101539359B1 (en) | Method for driving a light source, light source apparatus for performing the method, and display apparatus having the light source apparatus | |
| KR100867551B1 (en) | Led array driving apparatus | |
| KR100945205B1 (en) | Light emitting element drive device and mobile device using the same | |
| US8427073B2 (en) | LED driving circuit and backlight module | |
| CN101637065B (en) | Driver circuit for loads such as LED, OLED or laser diodes | |
| CN100481164C (en) | LED driver | |
| CN204244540U (en) | There is light-emitting component power supply circuit and the control circuit wherein of dimming function | |
| CN100365833C (en) | Light emitting element driving device and electronic apparatus having light emitting element | |
| KR100641260B1 (en) | Driving circuit | |
| US9257067B2 (en) | Light source driving circuit of light emitting semiconductor and backlight module | |
| US20060186830A1 (en) | Automatic voltage selection for series driven LEDs | |
| CN102237040B (en) | Driving circuit of light emitting diode, light emitting apparatus, electronic apparatus | |
| CN102088808B (en) | Contact current LED driving circuit of snap switch | |
| CN211237683U (en) | Backlight adjusting circuit and display device | |
| US9207458B2 (en) | Backlight driving board and LCD device | |
| KR20080009105A (en) | Drive circuit for supplying, based on control signal, current to load, and mobile information terminal incorporating the same | |
| KR20080026088A (en) | Light emission control circuit for lighting a plurality of light emitting elements, and illuminating apparatus and mobile information terminal having the same | |
| CN103365463A (en) | Method for controlling touch screens, controller and display system | |
| KR20120095245A (en) | Pwm controlling circuit and led driver circuit having the same in | |
| KR20130102406A (en) | Backlight unit and display apparatus having the same | |
| CN101527988B (en) | Light source driver module and circuit | |
| CN203378124U (en) | Projector LED light source drive module with single step-down converter |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20140319 Termination date: 20150227 |
|
| EXPY | Termination of patent right or utility model |