CN102685985A

CN102685985A - High-visual lighting effect driving method for LED

Info

Publication number: CN102685985A
Application number: CN2012101242013A
Authority: CN
Inventors: 邢先锋; 刘义芳
Original assignee: Xi'an Tesemi Technology Co Ltd
Current assignee: Xi'an Tesemi Technology Co Ltd
Priority date: 2012-04-25
Filing date: 2012-04-25
Publication date: 2012-09-19

Abstract

The invention discloses a high-visual lighting effect driving method for an LED (light-emitting diode). For an LED light source matrix, a 50Hz-400Hz pulse driving way with the duty ratio of above 50% is adopted for realizing high pulse luminous intensity under the same power, and a human eye visual persistence principle is utilized for realizing a high visual sensory lighting effect. According to the method disclosed by the invention, under the same power of the LED, the pulse current can be improved by 1/0.7 times, namely 1.4 times, although the absolute luminous intensity is reduced by 3%, the pulse luminous intensity is improved to be 1.35 times that during constant-current working, that is, the human eye visual brightness is theoretically improved by 35%, and the visual luminous efficiency is greatly improved; and by considering that the LEDs can be manufactured by different manufacturers, the LEDs have different working current properties, the visual luminous efficiency can be improved by 20% according to conservative prediction, the visual luminous efficiency and the energy-saving effect are significant, the human eye visual lighting effect can be greatly improved and a new way is provided for further energy conservation.

Description

The driving method of the high vision illuminating effect of a kind of LED

Technical field

The invention belongs to LED semiconductor solid state lighting technical field, relate to the driving method of the high vision illuminating effect of a kind of LED.

Background technology

Since the tradition, LED adopts constant current driven, and the luminous light intensity of LED is constant output.Illumination after all is people visual perception's a effect; It is that illuminating effect provides new approaches that human eye vision persists phenomenon; Human eye has the 0.1-0.4 retentivity time of eye of second, allows illumination can adopt frequency to be not less than the 24Hz pulsing light, simultaneously; The forward conduction frequency characteristic that LED is good makes pulsed drive become possibility.

Summary of the invention

The driving method that the purpose of this invention is to provide the high vision illuminating effect of a kind of LED can significantly improve the human eye vision illuminating effect, for further energy-conservation a kind of new way is provided.

The technical scheme that the present invention adopted is that the driving method of the high vision illuminating effect of a kind of LED is promptly for the led light source matrix; Adopt duty ratio more than 50%; The 50Hz-400Hz pulse drive mode under constant power, is realized the high impulse light intensity; Utilize human eye vision to persist principle, realize high visual perception's illuminating effect.

The invention has the beneficial effects as follows, through adopting duty ratio more than 50%, the 50Hz-400Hz pulsed drive; LED is with under the constant power; Pulse current has improved 1/0.7=1.4 doubly, though absolute light intensity has reduced by 3%, and when the pulse light intensity is brought up to constant current work 1.35 times; Human eye vision brightness has just improved 35% in theory, has improved the vision light efficiency greatly.Consider that LED has different manufacturing firms, different operating current characteristics, vision light efficiency improve 20% and belong to conservative and estimates, and vision light efficiency and energy-saving effect are remarkable, can significantly improve the human eye vision illuminating effect, for further energy-conservation a kind of new way are provided.

Description of drawings

Fig. 1 is existing C REE XP-ELED relative light intensity and drive current graph of a relation;

Fig. 2 is the type of drive oscillogram of the embodiment 1 of the inventive method, and T is the 100Hz driving pulse cycle, and duty ratio is 75%, and pulse current is 520mA, and 350mA is the manufacturer's standard drive current.

Embodiment

Below in conjunction with accompanying drawing and embodiment the present invention is elaborated.

The present invention is the driving method of the high vision illuminating effect of a kind of LED, is a kind of LED bright pulse driving method to the human eye vision organoleptic attribute, and its operation principle is:

Under the equal power condition of LED, establishing its power is P, and constant current value is IH during constant current work, and the forward operating voltage is VF; P=IH * VF so, during pulsed operation (referring to Fig. 2), pulse current is IM; It is little to consider that LED forward operating voltage changes with operating current, and the forward operating voltage still is VF when getting pulsed operation, and the pulsed operation duty ratio is D; P=IM * VF * D so, two kinds of patterns are compared, when power equates; IH * VF=IM * VF * D releases IM=IH/D, and visible impulse drives operating current can be bigger than constant-current driving;

The big drive current of LED can reduce absolute luminous efficiency, so must consider the luminosity curve like the LED of Fig. 1.Fig. 1 is an existing C REE XP-ELED product luminosity curve, and transverse axis is the constant-current driving electric current, and the longitudinal axis is luminous relative intensity; Can find out that drive current increases light intensity and also increasing, but the two is not in direct ratio; Relative intensity is 1 during 350mA, though also increasing greater than the 350mA luminous intensity, is not that direct proportion increases; Its light efficiency is reducing, and during 1A work, its relative luminous efficiency with 350mA light efficiency ratio is: 240% * (350/1000)=84%; Just light efficiency has reduced by 16%, in the practical engineering application, must consider this point;

So duty ratio is considered LED safety peak operation current (pulsed operation electric current) and light efficiency; The engineering limes superiors is not less than 50%, generally by about 75% designs, like this with under the constant power; According to IM=IH/D; Pulse current is no more than 2 times when adopting constant current, and with reference to Fig. 1, its absolute light efficiency is not less than 180% of constant current light efficiency * (350/700)=90%.When duty ratio was 70%, pulse current was that 1.4 of constant current is accompanied, 135% * (350/490)=97% when absolute light efficiency is not less than constant current;

Consider the LED switching characteristic, can ignore, consider the retentivity time of eye simultaneously less than 400Hz LED switching loss, adopt the 50Hz-400Hz pulsed drive all can, 2 times of power frequencies of the general preferred employing of engineering, i.e. 100Hz or 120Hz.

In sum, the technical scheme of the driving method of the high vision illuminating effect of LED of the present invention is, for led light source (matrix); Adopt duty ratio more than 50% (is example with 70%), 50Hz-400Hz pulsed drive (with 2 times of power frequencies, 100Hz/120Hz is an example); LED is with under the constant power, pulse current high during to constant current work 1/0.7=1.4 doubly, though absolute light intensity low 3%; But pulse light intensity (can know with reference to Fig. 1 curve) is high to 1.35 times, and this high light intensity pulse train is because the persistence of vision phenomenon of human eye; Human visual experience's brightness is high in theory 35%, has improved the vision light efficiency greatly.Consider that LED makes different manufacturers, the different operating current characteristics is conservatively estimated visual light usefulness and is enough improved 20%.

Embodiment 1

100W LED street lamp adopts 84 CREE XP-E LED, and 42 strings 2 are also made light source; Be equivalent to every LEDs and be operated in P=1.19W, LED forward operating voltage VF generally gets 3.1V, continuous current IH=P/VF=1.19W/3.1V=390mA; 100Hz frequency after the driving employing 50Hz rectification; Duty ratio is D=75%, and its pulse current is IM=IH/D=520mA, within the trouble free service electric current of XP-E 1A.

Drive waveforms in the practical application is as shown in Figure 2, and the relative light intensity that 390mA is corresponding is 110%, and the relative light intensity that 520mA is corresponding is 150%, and the pulse light intensity has improved 150%-110%=40%, and whole lamp visual effect is equivalent to 140W street lamp visual effect.Promptly adopt above-mentioned type of drive, people's vision increases 40% intensity according to effect, and theory is energy-conservation to reach 40%, and vision light efficiency and energy-saving effect are obvious.

Embodiment 2

Adopt the LED of 36 peak value constant current 800mA; Design the driving that a visual effect is equivalent to 50W: at first get frequency 100Hz, duty ratio D=80%, it is 50W that so actual 50W visual effect light fixture is equivalent to pulse peak power; Needing average power is 50W * 80%=40W

Every LEDs driving power is: P=40W/36=1.12W,

Need the driving pulse electric current to be: IM=(1.12W/3.1V)/80%=460mA,

Within the 800mA safe current, just adopt 100Hz, 80% duty ratio drives 36 (full string) LED, pulse current 460mA, actual power only needs 40W, just can realize the vision illuminating effect of 50W, energy-saving efficiency 20%, vision light efficiency and energy-saving effect are obvious.

Claims

1. the driving method of the high vision illuminating effect of LED is characterized in that: for the led light source matrix, adopt duty ratio more than 50%; The 50Hz-400Hz pulse drive mode under constant power, is realized the high impulse light intensity; Utilize human eye vision to persist principle, realize high visual perception's illuminating effect.

2. the driving method of the high vision illuminating effect of LED according to claim 1 is characterized in that: described duty ratio is preferred 70%, the preferred 100/120Hz type of drive of pulse.