Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers

Buy Site Supporter Role (remove some ads) | LPF Donations

Links below open in new window

FrozenGate by Avery

The REALLY Heavy Load - 30A test load

rhd

rhd

0
Joined
Dec 7, 2010
Messages
8,469
Points
0
The underside is meant to be attached to a heatsink / fan, like a CPU cooler. Thin aluminum will be used to level the various ICs, and then arctic silvered to the heatsink.

attachment.php


attachment.php
 

Attachments

  • IMG_20150402_201834.jpg
    IMG_20150402_201834.jpg
    68.4 KB · Views: 494
  • IMG_20150402_201902.jpg
    IMG_20150402_201902.jpg
    69 KB · Views: 450
Last edited:





Finally something to handle your drivers, eh?
The pic isnt very clear on my phone, are the jacks in the back the inputs/outputs, or the diode selection?
 
crazyspaz said:
Finally something to handle your drivers, eh?
The pic isnt very clear on my phone, are the jacks in the back the inputs/outputs, or the diode selection?
Click to expand...

Both. By choosing a jack, you choose the number of diodes.

There are also two jacks on the other half of the board for choosing between a 0.1 and 0.01 ohm sense resistor.
 
I have my doubts that SMD is appropriate for 30A. I would love to test this if you ever get a fully built version. I'd even pay return shipping. :shhh: I've got a thermal camera and a bench supply that considers 30A a 4% load.

rhd said:
Thin aluminum will be used to level the various ICs,
Click to expand...

Which of those are ICs?
 
Last edited:
rhd said:
Both. By choosing a jack, you choose the number of diodes.

There are also two jacks on the other half of the board for choosing between a 0.1 and 0.01 ohm sense resistor.
Click to expand...

Then what is the rectangular socket on the left side?
Also, where'd you get the PCB fabricated? It looks really, really nice!
 
Cyparagon said:
I have my doubts that SMD is appropriate for 30A. I would love to test this if you ever get a fully built version. I'd even pay return shipping. :shhh: I've got a thermal camera and a bench supply that considers 30A a 4% load.
Click to expand...

The version pictured used slightly cheaper TO252 diodes, and they're only rated for 15A average. Another revision that's otherwise the same swapped those for the 30A TO263 diodes. I may swap for TO220 though, with neutral tabs that can be heatsinked.

crazyspaz said:
Then what is the rectangular socket on the left side?
Also, where'd you get the PCB fabricated? It looks really, really nice!
Click to expand...

Dirty PCBs. They're as cheap as it gets. $14 shipped for 10 giant boards. They're great for things like this with big giant traces. Not great for things like drivers.

Oh, that socket is for DMM leads, but it's not great in practice. I'm going to find an alternative.
 
Last edited:
It looks really nice and professional! What type of diode needs near 30A!
 
Oh, one big thing to keep in mind that I've noticed with testloads;

Your resistor acts like a voltage drop too. Aka, if you're using a 1 ohm resistor, at 5 amps, it'll drop 5 volts on top of your diodes.

You'd need to use a much lower resistance if you still want the test load to work right. I'm sure you've thought of that though but still, just for anyone else reading.
 
Le Quack said:
Oh, one big thing to keep in mind that I've noticed with testloads;

Your resistor acts like a voltage drop too. Aka, if you're using a 1 ohm resistor, at 5 amps, it'll drop 5 volts on top of your diodes.

You'd need to use a much lower resistance if you still want the test load to work right. I'm sure you've thought of that though but still, just for anyone else reading.
Click to expand...

Two resistor options on this one - 0.1 ohm and 0.01 ohm :)
 
30 amps on 10mΩ is 9 watts of heat though. The choice of solder mask makes it difficult to see if you've used kelvin sense.
 
Cyparagon said:
30 amps on 10mΩ is 9 watts of heat though. The choice of solder mask makes it difficult to see if you've used kelvin sense.
Click to expand...

The resistors are through hole, so I'm not using the 90 degree kelvin leads that you'd use under a surface mount resistor. But I am using separate leads (not part of the current path) directly from the through holes, for vdrop measurement.
 
Are these being offered for sale? If so, please PM me, I don't always see responses.
 
I'd love to have one of these. I think I might try and build one my self..
 
You must log in or register to reply here.





Back
Top