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Current regulator and control method thereof

A technology of a current regulator and a control method, applied in the direction of regulating electrical variables, control/regulating systems, instruments, etc., can solve problems such as waste, unused dimming steps, complex calculations, etc.

Inactive Publication Date: 2009-09-02
RICHTEK TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, no matter in the low current area or the high current area, there must be some dimming steps that are not used, thus causing waste
In addition, complex calculations are required to select an appropriate dimming step, which also increases the difficulty of design
[0009] Therefore, there are above-mentioned inconveniences and problems in the known current regulator.

Method used

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Embodiment Construction

[0113] The present invention will be further described below with reference to the embodiments and the accompanying drawings.

[0114] In the known literature, the conversion formula between brightness Y and lightness L

[0115] L=116f(Y / Yn)-16 Formula 1

[0116] Among them, Yn is the brightness when it is completely white. f(Y / Yn)=(Y / Yn)1 / 3 when (Y / Yn)>0.008856, otherwise f(Y / Yn)=7.787(Y / Yn)+16 / 116. It can be deduced from formula 1

[0117] f(Y / Yn)=((L+16) / 116) Formula 2

[0118] Since the range of (Y / Yn)<0.008856 is very small, it is negligible, so it can be further deduced

[0119] (Y / Yn)=((L+16) / 116)3 Formula 3

[0120] Therefore, as long as the brightness emitted by the light-emitting diode conforms to formula 3, it can conform to the brightness change perceived by human eyes. For more details, please refer to the webpage http: / / en.wikipedia.org / wiki / Lab_color_space.

[0121] First see Figure 7 , Figure 7It is the figure of the first embodiment of the present i...

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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 [0001] The invention relates to a current regulator for driving a white light LED, in particular to a current regulator and a control method thereof which can make the brightness change of the white light LED change linearly in human eyes. Background technique [0002] Due to the advantages of low power consumption, long life, small size and low cost, light-emitting diodes (LEDs) are attracting more and more attention. figure 1 A known current regulator 10 for driving a white LED 20 is shown, which includes a current source 12 for supplying a current IREF, the drain of a transistor 16 connected to the current IREF and the non-inverting input of an operational amplifier 14, the source of which is connected to ground GND, its gate is connected to the output of the operational amplifier 14, the drain of the transistor 18 is connected to the LED 20 and the inverting input of the operational amplifier 14, its source is connected to the ground terminal GND, its gat...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H05B37/02G05F3/26
Inventor 林水木黄宗伟陈健生朱冠任
Owner RICHTEK TECH
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