Industry news

2016August

Design techniques and methods of LED lighting

From: www.szbako.com Data:06/08/2016

LED lighting design
a, to determine the lighting requirements:
1, this design is an alternative to the existing lighting structure or to meet the customer's special lighting to
.
2, listed in the design of the key performance requirements, minor performance requirements, the performance requirements are not important.
2, to determine the design goal:
the performance requirements of the indicators listed. For example: light output (LM), optical power ratio (W), luminous efficiency (LM /W), lighting area and shape, color index, color temperature (k), industry and trade as ring environment temperature (OC), life, into the.
3, estimation of optical, thermal and electrical system efficiency of
1, the efficiency of optical system:
optical system efficiency mainly consider light to reach the target illumination before meeting the lens, optical devices, anti light microscope in the main absorption rate or reflectivity and secondly need to consider the loss of light Zhao Mingmu standard.
2, thermal system efficiency:
according to the working environment temperature to determine the junction temperature LED → combined with LED product data to determine the relative light output at this time. The optical output of
25 degrees C should be designed with the minimum value (Minimum) instead of the typical value (Typical).
3, electrical system design
mainly consider the driving power factor, we design should make the load accounted for more than 50% of the power source of the


source, so that more efficient use of drive efficiency. Calculate the number of required led
1, according to the requirements of the optical and thermal system of the system efficiency and light output target, calculate the real needs of the luminous flux.
2, select LED
3, determine the drive current /voltage. 4, calculate the required LED number
five, considering the feasibility of the entire design and select the best design scheme
consider the design needs to comply with the standards: electromagnetic interference standards, safety standards, efficiency standards. 1, optical system design:
main considerations: * light spot shape (Illuminancedistribution), the effect (multiple-source shadow), beautiful.
scheme A, LED+ existing mirror
advantages: low cost
light loss small
assembly convenient, reduce process steps, reduce labor costs. Disadvantages: there are many shadow effects
beam angle is not controllable.
Plan B, a single led by optical elements existing in the secondary optical design + mirror
advantages: angle beam design can be free control
disadvantages: cost than a high
there are many shadow effect Mr. light loss than design: the design of a
C, led the existing mirror * lens (diffuser)
advantages: than a program can obtain more wide beam angle
does not exist defects in the shadow effect more than
: cost high
light loss big
such as the lighting requirements of the beam angle is greater than the independent LED light beam angle, this scheme is infeasible.
job requirement:
, thermal system design:
main consideration factor: lighting costs, design cycle, goals of environmental temperature scheme 1, the existing structure
scheme 2, the market purchase scheme 3, a self-designed
for independently design requires the designer will design simulation software or can use thermal design experience.
Tj= Ta+ (Rth B-A? Ptotal (Rth) + j-sp? PLED)
↓ ↓




LED junction temperature cooling system temperature resistance LED LED total power of the thermal resistance of single LED power






LED data design goal to design LED the number LED
LED number
slander IF
working current available the determination or check the products according to the data of

?

junction temperature data
working voltage of VF (@IF)
3 design, electrical system:
main factors: the efficiency of


schemes available design resources and the goal of the 1, on the market the purchase of
2, and R & D drive scheme to develop the next generation of LED drive program 3, designed by
six, the final step:
1, map 2, first, the first 3 Sample test
4, correction and out of the document 5, summed up the text in the &ldquo
; *” place, translation may be wrong, please help correct, be grateful! Personal summary of the back of the brain there are some of the following questions can not be clear, please peer guidance,
!!
1, what are the main factors that affect the heat dissipation system?
job requirement:
, led afraid of inrush current, although the current design we used is constant current or constant voltage drive, but is still often appear connected or disconnect the power when the burn led, with what method can solve this problem?
3, the number of LED layout on a circuit board, our company said its LED module. How to detect and judge the working temperature of the module automatically? How to adjust the IF according to the working temperature, so that the LED is not so serious?
RELATED NEWS