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A niche chip (LT4320) for mains powered AC -> low volt DC "linear" based psu ?

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digsys:

--- Quote from: resistor ---  So... how did the prototype turn out? 
--- End quote ---
Funny you ask .. All PCBs assembled and wired up, was about to Solder in the FETs I chose, but just found out the parts
are on hold because the account wasn't paid .. GRRRRRR
I'll probably just use the 25mR FETs I have, instead of the 0.9mR - 1.9mR that are on hold, at least just to prove it and
get a few readings (with my FlirE48+ :-) )  Hopefully answers in a few hrs

BravoV:
BTW, just noticed there is an update in the datasheet, and apparently its now available in DIP 8 package  :clap:, great news for hobbyist who want to build a traditional AC to DC step-down transformer based linear power supply.

digsys:

--- Quote from: BravoV ---BTW, just noticed there is an update in the datasheet, and apparently its now available in DIP 8 package 
--- End quote ---
Just when I perfected my thermal pad artwork and soldering method :-)
Preliminary results - as per PCB linked before - Using CSD18502KCS NFET, TO220, RDSon=2.4mR, GateCap=3900pF
FETs bolted to a double sided PCB x3oz using Arctic Silver and no other heatsink
Ran at 10A continuous for several minutes - 4,700uF and 16,700uF - FETs barely warm.
- as above but at 15A continuous - FETs quite warm, but not too hot to touch.
The waveforms were the most impressive, absolutely clean with no detectable switching steps, in all conditions.
I'll run harder tests tomorrow, along with Flir images. So far - VERY impressed. The test PCB should go to 30A.

BravoV:

--- Quote from: digsys on November 28, 2013, 02:21:41 pm ---
--- Quote from: BravoV ---BTW, just noticed there is an update in the datasheet, and apparently its now available in DIP 8 package 
--- End quote ---
Just when I perfected my thermal pad artwork and soldering method :-)
--- End quote ---

LOL ...  ;D , also curious why LT made such package, I thought thru hole is dead ?  :-//

Anyway, its so new, when I tried the LT's online shop, the DIP version still not available.



--- Quote from: digsys on November 28, 2013, 02:21:41 pm ---Preliminary results - as per PCB linked before - Using CSD18502KCS NFET, TO220, RDSon=2.4mR, GateCap=3900pF
FETs bolted to a double sided PCB x3oz using Arctic Silver and no other heatsink
Ran at 10A continuous for several minutes - 4,700uF and 16,700uF - FETs barely warm.
- as above but at 15A continuous - FETs quite warm, but not too hot to touch.
The waveforms were the most impressive, absolutely clean with no detectable switching steps, in all conditions.
I'll run harder tests tomorrow, along with Flir images. So far - VERY impressed. The test PCB should go to 30A.

--- End quote ---

Thanks for sharing this.  :-+

Sounds quite impressive, and 15A for my personal project should be more than enough.  :clap:

Please, if it's not troubling you too much, share few scope's shots the waveforms you mentioned above, also could you please do a startup capture, just curious to how it performs when turned on for the 1st time.

Btw, those tests were done at what voltage ? and whats your expectation or target on the current at your circuit ? 30 Amp ?  :o

digsys:

--- Quote from: BravoV ---Btw, those tests were done at what voltage ? and whats your expectation or target on the current at your circuit ? 30 Amp ?
--- End quote ---
Ran them at 5VAC and 25VAC. Next I'll check lowest AC possible and a max of 35VAC (These FETs are only 40V)
I need to see that they run perfectly fine at 30A, in our 20A units. Still waiting for other FET types, including the 0.9mR ones.

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