I meant, instead of having one big heatsink for 4 mosfets... how about putting one per mosfet? One of those famous to-220 heatsinks. Will it work?
If your device is about 100 watts that means 25 watts per mosfet, so my question will such heatsink be able to tolerate these 15-25 watts? with or without fan cooling.You need to specify which heatsink you are thinking, a pict would do.
Usually they are kind of small and good for LM137 when you need a bit more umpf out of it without them.
JS
I meant, instead of having one big heatsink for 4 mosfets... how about putting one per mosfet? One of those famous to-220 heatsinks. Will it work?
If your device is about 100 watts that means 25 watts per mosfet, so my question will such heatsink be able to tolerate these 15-25 watts? with or without fan cooling.You need to specify which heatsink you are thinking, a pict would do.
Usually they are kind of small and good for LM137 when you need a bit more umpf out of it without them.
JS
I meant one of these:
https://www.aliexpress.com/item/5pcs-lot-38x34x12-8mm-TO220-TO-220-heatsink-heat-sink-radiator-for-IC-triode-7805/32622932747.html
and these are more quality ones (branded): https://eu.mouser.com/ProductDetail/Ohmite/FA-T220-64E?qs=sGAEpiMZZMttgyDkZ5WiumlCfl50RTwzVA%252bY4U4BtvA%3d
And in the end of the case (inside) one of these small fans: https://www.aliexpress.com/item/High-quality-3010s-30MM-30-x-30-x-10MM-12V-2Pin-DC-Cooler-Small-Cooling/32603431500.html
so 4 heatsinks close to each other and one fan sucking air from them and toss it outside.
I tried searching for one big heatsink but couldn't find a standard one. So this project, what heatsink comes with it? or should you put a heatsink of your own?
Say I want to make such a project which will be sold as a commercial open source one... okay? now how can I source heatsink if there are no standard ones? especially a cheap one with a fan to make it affordable.
So you think one heatsink is better than 4 smaller ones? perhaps you are correct since it could dissipate all the heat better but I don't really know.
The heat-sink, fans and power MOSFETs have arrived.
I purchased ten IRFP4668 130A 200v MOSFETs on eBay with a view to selecting 4 matched ones.
I will publish how I tested and matched them shortly.
The heat-sink measures 150x69x36 also purchased on eBay. I do not have any thermal specs for it.
The fans are 70x15mm 12v units from eBay
enut11
The heat-sink, fans and power MOSFETs have arrived.
I purchased ten IRFP4668 130A 200v MOSFETs on eBay with a view to selecting 4 matched ones.
I will publish how I tested and matched them shortly.
The heat-sink measures 150x69x36 also purchased on eBay. I do not have any thermal specs for it.
The fans are 70x15mm 12v units from eBay
enut11
Can you please provide the links and prices? shipping?
Also, I would be interested to see what is the performance of heatsink alone at say 5A compared to with fan. I hope you can do that, you would benefit us.
One way you can determine heatsink temperature coefficient, it is by recording its temperature at no current (= ambient) then put a known power like 1W and measure its temperature, then repeat with 10W... finally you will get to know the coefficient.
Hi @JS
Interesting circuit. Have you Posted it separately on the Forum? Should raise some useful discussion.
Temp control on mine is manual. Awaiting for these controllers to arrive for testing.
https://www.ebay.com.au/itm/Temperature-Speed-Controler-DC-12V-Denoised-Speed-Controller-for-PC-Fan-Alarm/132595582255?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649
I have yet to think about step response. That will come later.
I like the ability to switch CV/CC.
enut11
According to SOA on the datasheet IRFP4668 can handle:
500W @ 5V (not a realistic value, limited by Thermal Resistance)
30W @10V
10W @20V
So I don't think that is suitable for your application.
Where did you get such info?
I used IRILZ44N for my design for 30v/2A specs, it could go much more. It is in an isolated package which is a plus.
Yes, case-to-heatsink thermal resistance is a bitch, with 4 transistors they are kind of in parallel, so you expect to see the same thermal difference in that juncture if using the same mounting technique. Anodized heatsinks from a respectable vendor might have enough anadization to be considered enough insulation, if you need them to be isolated.
Other improvement that could be made is to use a better thermal paste, any decent metal based PC grade is an improvement over regular silicon based ones.
As mentioned cooper plates might be helpful, as it's softer than aluminum might get better contact for the same pressure and then you have a greater area from the cooper to the aluminum and the cooper softness helping here again.
JS
Enviado desde mi LG-M250 mediante Tapatalk
How about this panel meter that you use?
I read that it doesn't go to lower voltages, is that correct? can it be mounted high-side and low-side?