Thermal Switch

Hello!

I'm trying to implement a thermal switch for my strip build and so far I found these ones on digikey:

Cantherm F20A
https://www.digikey.com/products/en?dc=6418

Click to expand...

ChilLED was also selling them on their website and they probably use them in their systems.

Should I use one per strip? Or one per driver?
How they should be wired?
Which one should I pick based on a strip build? There are many different switching temperatures and reset temperatures.
Do I even need them? Each diode will be run at 50mA.

Thanks in advance!

My build:

LED
DigiKey
28 x LM561C F Series FB22B Linear Strip 3000K 80CRI (SI-B8V521B20WW)

Driver
Mouser Electronics
1 x Mean Well HLG-600H-48A

~446mA each strip, ~50mA each diode

Click to expand...

Takeshy said:

Hello!

I'm trying to implement a thermal switch for my strip build and so far I found these ones on digikey:


ChilLED was also selling them on their website and they probably use them in their systems.

Should I use one per strip? Or one per driver?
How they should be wired?
Which one should I pick based on a strip build? There are many different switching temperatures and reset temperatures.
Do I even need them? Each diode will be run at 50mA.

Thanks in advance!

My build:

Click to expand...

Ok, nice little component, simplest way of implementation would be on the dimmer circuit of your drivers if you have dimmable drivers, if not it would need to be placed on the low voltage side of a relay. As to where and how many, at least one per heatsink, positioned central to the hottest part, you can run wires as long as you need as there will be fuckall current involved. If you have dimmable drivers, I worked out a way of achieving a similar level of thermal protection using NTC thermistors on the dimming circuit which has the advantage of thermally regulating rather than simply turning the whole rig off in an over temp situation, a thermistor changes resistance with temp so can be used in place of or in addition to a dimming potentiometer and simply lower the driver output if temps get high then turn them back up if it cools down.
Here's the little instruction vid I did about it;

Here's How I Wired Up my Inventronics Driver to Thermal Switched

How about the switching temperature? 70ºC? 75ºC? 80ºC?

Thanks!

Takeshy said:

How about the switching temperature? 70ºC? 75ºC? 80ºC?

Thanks!

Click to expand...

I'd say that depends on what you are wanting to protect, if you want to protect your cob's, then 70C, if you are wanting to ensure your rig don't burst into flames and burn the house down then 80C. Bear in mind the max junction temps are taken from the sensor point on the cob substrate, if you are reading temps thru the back of the heatsink it will be several degrees lower readings than actual cob temp so you need to either measure or guesstimate this difference. I tend to aim for heatsink temps in the 40-60C range so a 70C regulator would be my choice.

freemanjack said:

I'd say that depends on what you are wanting to protect, if you want to protect your cob's, then 70C, if you are wanting to ensure your rig don't burst into flames and burn the house down then 80C. Bear in mind the max junction temps are taken from the sensor point on the cob substrate, if you are reading temps thru the back of the heatsink it will be several degrees lower readings than actual cob temp so you need to either measure or guesstimate this difference. I tend to aim for heatsink temps in the 40-60C range so a 70C regulator would be my choice.

Click to expand...

I'm now between these 3 thermal switches:
https://www.digikey.pt/products/compare/en?RI=516_0_0_1000011_0_0_0_0_0_0_0_0_0_0_|ffe81912,b7c000a,ffe00204,2080009&allpart=on&part=317-1321-ND&part=317-1000-ND&part=317-1038-ND&allpart=on

Price is the same but I can't see any difference between them.

Takeshy said:

I'm now between these 3 thermal switches:
https://www.digikey.pt/products/compare/en?RI=516_0_0_1000011_0_0_0_0_0_0_0_0_0_0_|ffe81912,b7c000a,ffe00204,2080009&allpart=on&part=317-1321-ND&part=317-1000-ND&part=317-1038-ND&allpart=on

Price is the same but I can't see any difference between them.

Click to expand...

OK well one is outta stock, the other two are identical specs but are listed as different part numbers because one has wire leads the other has through hole pins, thats the difference, you probably wanna go with the soft wire version; 317-1000-ND