led lamp detailed design parameters

8/22/2019 LED Lamp Detailed Design Parameters

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International Journal of Engineering Trends and Technology (IJETT) - Volume4Issue5- May 2013

ISSN: 2231-5381 http://www.ijettjournal.org Page 1434

LED Lamp Detailed Design

ParametersK. Ajay Sai Mohan#1,

#ECE Department, K L University,

M. Anil Kumar*2

,

Asst.Professor, ECE Department, K L University,Vaddeswaram, Andhra Pradesh, India.

Abstract:-Light by definition is the form ofelectromagnetic form of energy that has a wavelengthfrom 400nm to 700nm of visible light. All humanactivities are done round the clock. Before we go any

further, it is worth looking at definition for lighting.We say the lighting is good, when our eyes canclearly and pleasantly perceive the things around us.

So Artificial light should be Functional and pleasantboth Physiologically and Psychologically. This is oftenachieved employing multiple sources. Also the form of

energy should be efficient and usable by everyone. Asall of us are aware, all sources today employ electricalenergy.

Keywords:- Lumen, Wattage, Pitch, Diffuser Sheet,

Troffer.

I. INTRODUCTIONLight is the Radiant Energy that providesvisual sensation. It is similar to radiant heat.

But has different frequencies andwavelengths. However, Visible Light

spans from 180nm to 700nm wavelength.

It must be mentioned that human Eye

responds from 380 (violet) to 700nm (red).

This becomes necessary for us to

understand the suitability of various types

of sources of light.

II. DESIGN PROCEDURE

A. PCB of LEDs is designed based onvarious parameters:1. Estimation of LUMEN.2. No of LEDs required.3. Selection of resistor.4. Selection of reflector material.5. Pitch and height.B. Estimation of LUMEN:

Whenever we need to design alamp first we should know how much

lumen that the lamp should produce. The

amount of lumen depends upon the room

in which the lamp should be installed, at

what height the lamp should be placed and

the area the lamp should cover.C. No of LEDs required:

6. Total number of LEDs = TotalLumens required / LED Lumen

7. Total number of Bunches Total LEDs/ LEDs per Bunch

8. Total current=Each LED current *Total Bunches

9. Total Voltage = LED cut in voltage *No: of LEDs per Bunch

10. Total Wattage = Total current * Total

voltage11. Efficacy obtained with out diffuser =

Lumens obtained / WattageEach Lamp contains a Diffuser sheet,

there obtained a loss of 35% Lumen.

Lumen obtained after the addition of

diffuser sheet = 65% (Lumen without

diffuser) Losses due to diffuser sheet has

to be compensated by addition of LEDs to

maintain the required Lumen.1. No. of LEDs to be added = Drop in

the Lumen / Each LED Lumen2. Total bunches with diffuser= Total

LEDs with diffuser/ LEDs per Bunch

3. Total current with diffuser= EachLED current * Total number ofBunches with diffuser

4. Total Wattage with diffuser= Totalcurrent with diffuser * Total voltage

5. Total Efficacy with diffuser = Lumensobtained with diffuser / Total Wattage

with diffuser


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Based on Lumens required, the trofferparameters are designed.

7.5W 1 X 1 Troffer(osrum)

Lumens

Required706

Cut in Voltage 2.94

LED

current(mA)20

LED lumen 8.55

Wattage

Obtained7.47

Lumens with

diffuser706.00

Total LED'swith diffuser 127.04

Total Bunches

with diffuser18.15

Measurment Of troffer

Lenght (Feet) 1

Width (Feet) 1

Length

(Centimetre)30.32

Width

(Centimeter)30.32

Cut in AreaLength(Centimeter)

28.32

Width

(Centimeter)28.32

No of columns 11

No of rows 11

Column pitch 2.51

Row pitch 2.51

Total Efficacy

with diffuser

(lm/W)

94.52

Efficacyobtained with

out diffuser

145.41

PCB type Single side

No: of LEDs 121

Osrum cost 302.5

Nichia cost 544.5

III. SELECTION OF RESISTOR

Never connect an LED directly to

a battery or power supply. It will bedestroyed almost instantly because toomuch current will pass through and burn it

out. LEDs must have a resistor in series to

limit the current to a safe value. Resistor

value is selected based on the cut-in

voltage and forward current of the LED

used.

IV.SELECTION OF REFLECTOR MATERIAL

Reflecting surfaces are used mainly to get

uniform illumination. There are two types

of reflector sheets that are used in troffer

lighting. One is glass and the other is

poly-carbonate sheet. Now a days diffuser

sheet is used .Killing of lux is observed

nearly up to 35%(loss). To compensate the

losses LEDs are added.

V.PITCH AND HEIGHT

PITCH : The distance between two

adjacent LEDs in PCB .

HEIGHT : Height at which the reflector

sheet is placed. It is decided based on

the requirement of LUX and illumination.

By using these concepts we design troffer

lights of required wattage and lumen.

VI. BASED ON WATTAGE

A. Estimation of Wattage:Whenever we need to design a

lamp first we should know how muchwattage that the lamp should produce. The

amount of wattage depends upon the roomin which the lamp should be installed, at

what height the lamp should be placed andthe power the lamp should cover.


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10W 1 X 1 Troffer(nich ia)

Lumens Required 706

Cut in Voltage 2.95

LED current(mA) 40

LED lumen 13.50

WattageObtained

9.49

Lumens withdiffuser

706.00

Total LED's withdiffuser

80.46

Total Buncheswith diffuser

11.49

Measurement Of troffer

Length (Feet) 1

Width (Feet) 1

Length(Centimeter)

30.32

Width(Centimeter)

30.32

Cut in Area

Length(Centimeter)

28.32

Width(Centimeter)

28.32

No of columns 9No of rows 9

Column pitch 3.16

Row pitch 3.16

Total Efficacywith diffuser(lm/W)

74.36

Efficacyobtained without d iffuser

114.41

PCB type Single side

No: of LEDs 80

Osram cost 201.14

Nichia cost 362.05

B. No of LEDs required:

1. Total voltage=LED cut-in voltage *Total No:of LEDs per bunch

2. Total current=Total Wattage / Totalvoltage

3. No: of bunches=Total current / LEDcurrent

4. Total No: of LEDs=No: of bunches *No: of LEDs per bunch

5. Total lumen=Total No: of LEDs *Each LED lumen

6. Efficacy of lamp=Total lumen / Totalwattage

VII.CONCLUSION

This design helps to design a lamp

effectively with more efficiency based on

lumens and wattages, thus give the best

results in the longevity of the lamp.

REFERNCES

1.http://en.wikipedia.org/wiki/Printed_circuit_board

2.S Muthu, J Gaines - IAS Annual

Meeting. Conference Record of , 2003 -ieeexplore.ieee.org

4. G Zorpette - Spectrum, IEEE, 2002 -

ieeexplore.ieee.org

led lamp detailed design parameters

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