C.O.B.S.S.L. News and Articles

stardustsailor

stardustsailor

Well-Known Member
Why It's better to use an array-COB holder ,
even if the cob(s) I use have already holes for screwing down ?

adapter.JPG

White color on the thermographic pics denotes high temperature
Blue color denotes low temperatures .

Notice the d) case ,how much cooler the cob operates ,
with the combo connector/holder & thermal grease ,as TIM.

Screwing down ,might cause uneven pressure on the COB -heatsink
contacting surfaces.

Let alone to leave the cob as it is ,sucked by the thermal grease's viscosity
or 'securing' with Kapton / alum tape ...
A definite No-No !


For Cree CXA30xx series :

Ideal array holder 50-2234C

http://www.idealind.com/products/oem/led_holders/cree.jsp
http://www.idealind.com/media/pdfs/products/instructions/ND_7868-6_50-21_Instructions.pdf
http://www.idealind.com/media/pdfs/products/specsheets/chip-lok_spec_sheet_combined.pdf
 
stardustsailor

stardustsailor

Well-Known Member
Cob basics :
cob basics.JPG

Cover/lenses and reflectors may be used to 'accommodate' the output light in cases such as of small or large spaces without any reflective surroundings or high-ceiling / large overhead distances .

A holder/connector is the most preferable/favourable /efficient way of attaching a COB to a heatsink .

Good heatsink preparation and a quality TIM (pref: grease ) will enhance cooling .

Heatsink has to be large enough and or designed appropriate ,to handle the heat generated by the COB(s).

Driver(s) has(-ve) to be of Constant Current (CC ) (dimmable or not )
and they must deliver the appropriate Vo range ,
matching the Vf range of the COB(s) ,in direct relation with Tcase* and If **.-

*Check at COB's technical datasheet for the " Tc vs Vf " graph
**Check at COB's technical datasheet for the " If vs Vf" graph
------------------------------------------------------------------------------------------------------------------------
Add a 12 Volt DC Fan and a Constant Voltage (CV )12 VDC Power Supply Unit (PSU ).,
if you want active cooling ,instead of passive.

Smaller diameter fans of high speed ( i.e. 80 mm / 3200 rpm ) are better suited to pin fin heatsinks or with long-thin fins ,closely placed.

Larger diameter fans of low speed (i.e. 140 mm / 1000 rpm )are better suited to short-thick fins, spaced apart .



Abbrev.:
Xo= Output , i.e. Vo = Output Voltage
Xf= Forward Drop , i.e. Vf =Forward voltage drop of a diode
Xi= Input , i.e. Vi = Input Voltage
Xr= Receiving Signal (for PWM application), i.e. PWMri =PWM receiving signal input pin/wire
Xt =Transmitting Signal , i.e. PWMto = PWM transmitting signal output pin or wire .

Tj= Semiconductor Junction Temperature.
For most COBs : Tj =Tc ( Case Temperature ) =Tsp (Solder Point Temperature )

V=voltage
I=Current
P=Power
T=Temperature
Click to expand...
 
Last edited:
FranJan

FranJan

Well-Known Member
smokey the cat

smokey the cat

Well-Known Member
stardustsailor

stardustsailor

Well-Known Member
Modes of Driving a L.E.D. array / Chip -On-Board L.E.D. module

There are three modes of driving a L.E.D. array / Chip -On-Board L.E.D. module .
HE ,NM & HO ...

-HE stands for " High Efficiency " mode .Driving up to 50% of maximum power dissipation.

For example,driving a CREE CXA3070 up to 1400 mA .
High Efficiency,but low output mode.

-NM stands for " Nominal " mode .Driving from 50% up to 75% of maximum power dissipation.

For example,driving a CREE CXA3070 ,from 1400 mA up to 2100 mA .
Balanced efficiency versus output mode.

-HO stands for " High Output " mode .Driving from 75% up to 100% of maximum power dissipation.

For example,driving a CREE CXA3070 ,from 2100 mA up to 2800 mA .
High output,but low efficiency mode.

-----------------------------------------------------------------------------------------------------------------------
From Tridonic :
modes.JPG


http://www.tridonic.com/com/en/products/talexxmodule-stark-fle.asp#tab4

1750 mA ( 50% of 3500 mA ) is HE mode .
2600 mA (~75% of 3500 mA ) is NM mode .
3500 mA (100% ) is HO mode .
 
stardustsailor

stardustsailor

Well-Known Member
Tridonic : A COB for every occasion ...

Inspired by light

Just think of a sunset at the beach, a romantic campfire or the dazzling skyline of a city at midnight ... light is naturally able to create experiences that inspire people. We offer you various component solutions to build exactly the setting you need: Luminous colours and colour temperatures to let products and employees shine. Enter the world of “Emotional Lighting” with Tridonic – for retail and office applications.

http://www.tridonic.com/com/en/news-inspired-by-light.asp


For fashion shows and clothing boutiques ...

fashion.JPG


For bakery goods and fresh or cooked meat !!!
food.JPG


For art and culture ...
art.JPG


From 2700K to 6500 !!! ( Red + NW + (? blue / cyan ? ) led array module )

http://www.tridonic.com/com/en/download/technical/TALEXXengine_STARK_SLE_PREMIUM_guide_en.pdf

tunable cct.JPG





.....
But then ,what about a cob for plants ?
......
Well ..
It really seems that plants not just ' settle ' (light adaption ) with every each different COB / array ...
In fact they "love" the majority of them ...
They trully flourish ,no matter which the cob is ...





https://www.rollitup.org/t/another-cree-cxa3070-diy-thread.824364/page-20#post-10987606



Still attending black plants in a violet-pink universe ?
.......:roll:
 
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stardustsailor

stardustsailor

Well-Known Member
Cree CXA3070-0000-000N00AB30 H/F :
Radiometric efficiency vs Case Temperature (30°-60°C ) vs Forward Current (400-2800mA ) chart & graph.

Luminous Efficiency of Radiation ( 3000°K -CRI 80 ) : 325 Lumen / Watt
1111.JPG

2222.JPG
( HSF : Estimation with highly efficient Heat sink-Fan cooling. Ta=25 °C.)

Mode HE 400-1400 mA : Radiometric efficiency range tops at 52,2% (Tc=30 @400mA ),
& drops at 38.8 % (Tc=60 @1400mA ).

Mode NM 1400-2100mA : Radiometric efficiency range tops at 41.3 % (Tc=30 @1400mA ) ,
& drops at 33.3 % (Tc=60 @2100mA ).

Mode HO 2100-2800mA : Radiometric efficiency range tops at 35.6 % (Tc=30 @2100mA ) ,
& drops at 28.4 % (Tc=60 @2800mA ).


In real life applications ....
With a highly efficient HSF cooling system ,ambient temperature =25C :
HE mode starts at ~400mA and has a whopping 52,2% rad.efficiency .(Tc=30C )
HE mode shall have around 40% radiometric efficiency at 1400mA .(Tc=45C)
NM mode shall have around 34% radiometric efficiency at 2100mA .(Tc=55C)
HO mode shall have around 28% radiometric efficiency at 2800mA .(Tc=70C )


D.I.Y. Note :

It will be wise enough never to run any type of COB at HO mode .
(75%-100 % of max power dissipation) .
Yeap,better to forget about any kind of "HO operational mode".
It's counter -productive ,energy-consuming,the COBs shift to cooler CCT ,their service life decreases,cooling needs in power terms are 'way out of line' and many more bad-bad things are waiting ,hidden behind the "HO operating mode" .

The rest :

*High Efficiency Mode -(up to 50% of COB's max power.)
One efficient way of course ,is to run HE mode ,and 'make up ' for the low output ,
by using more units of COBs.Cooling is also somewhat easier as an aspect,as of dealing with lower heat power per COB unit.Light spreading & power distribution also ,are close to optimum.The drivers may be dimmable ,offering greater versatility / power savings in case of seedlings/clones/SOG/SCROG/"MILK s".(Mothers I'd Like to Keep .)

* "Pure HE" -
As before ,but the drivers are not dimmable,having a preset output current.
Thus they operate at high efficiency.Most efficient way .

* High Efficiency Mode & Nominal Mode -(up to 75% of COB's max power)
Another way will be using less units of COBs but more powerful drivers ,running the COBs
at NM mode ...Not as efficient way ,but allows for smaller light fixtures.Thus ,a more preferable way for tighter budgets and /or tighter available spaces.Cooling becomes a serious issue,in such case.Use of optics (reflectors mainly),may prove a real enhancement / aid ,also.


* "Multi HE&NM " .(HE & NM modes / multiple units )
Use of multiple COB units / fixtures ,driven with dimmable high power drivers.
Plenty of units & plenty of available power.
The most 'versatile' & 'powerful' ,but also most expensive way .
(Still not as efficient as a "pure HE". Total efficiency is COB eff. multiplied by PSU eff.
Dimmable drivers have their highest efficiency when operated to their full load or close.
So ,at low currents of HE operating mode ,a dimmable high power driver will 'under-perform' counter-acting the high efficiency of COBs ,thus the total efficiency will be decreased,compared to a pure HE mode system using non-dimmable drivers .)
Click to expand...
 
Last edited:
FranJan

FranJan

Well-Known Member


Philips Luxeon COBs
http://www.philipslumileds.com/



LUXEON COB Application Brief:
http://www.philipslumileds.com/uploads/426/AB115-pdf
LUXEON COB Product Datasheet:
http://www.philipslumileds.com/uploads/419/DS115-pdf

Luxeon with Crisp White
2 - Copy.png​
LUXEON CoB with CrispWhite Technology Product Brief:
http://www.philipslumileds.com/uploads/483/PB138-pdf
LUXEON CoB with CrispWhite Technology Datasheet:
http://www.philipslumileds.com/uploads/482/DS138-pdf
Features & Benefits​
  • 90CRI with CrispWhite enhancement for perfect combination of warm colors and white that stands out!
  • Hot targeted within a 3-Step MacAdam Ellipse below the BBL that is ideal for CDM-CMH replacement
  • Creating a second blue peak (~410-415nm) in the spectrum that activates fluorescent whitening agents paints/fabrics
  • Lumen packages from 1,000 to >5,000 lumens and efficacies of >90 lm/W
  • Real world application testing conditions at Tj=85°C
  • Robust MCPCB solution - easy to handle in manufacturing and operations
  • Mousebites for M2/M3 easy to screw down arrays
 

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