DIY Resistive Load bank

Thread Starter

ak2011

Joined Oct 24, 2011
12
Would also like some help on creating a load bank. Haven't done one before...but would like to create an electronic load bank that I can switch with logic (transistor-based??)

I have two DC/DC bricks producing 12VDC and 5VDC. I want to be able to load each rail from 0.5A to 5A, in 100mA steps. Any help is greatly appreciated...

Thanks!
 

Thread Starter

ak2011

Joined Oct 24, 2011
12
thanks, this should work. maybe i can use a digital pot to electronically control the current load.

thanks again
 

Thread Starter

ak2011

Joined Oct 24, 2011
12
So I modified another example I found online, and simulated it (see attachment)...seems to work. Seems too simple...any suggestions on add-ons? (e.g. protection diodes, etc). This circuit can load the DUT with up ~12A
 

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chrisw1990

Joined Oct 22, 2011
551
yeh not a bad idea using the digital pot, how you then provide feedback to the IC controlling the pot is up to you, one thing though, why use a regulator for the power? with only 100mA perhaps a zener would be more appropriate - like the design i showed you? whats the 12V source you're using?
also, have you calculated the current sense resistor? or borrowed one of another design?
 

Thread Starter

ak2011

Joined Oct 24, 2011
12
Zener is probably a good idea instead of the LDO...the 12V supply will be from an ATX supply

Current sense resistor was borrowed from another design. I like the 0.1 (if I can find one) to minimize power dissipation (a higher value resistor would mean more power)
 

chrisw1990

Joined Oct 22, 2011
551
also, unless you only have the lm324 (while im pondering over it) why not use an alternative single opamp? less waste and potentially less cost, though a dual is probably going to cost less =]
anddd maybe.. might be worth putting a back up passive overcurrent system in place?
just in case the digital side fails?
 

Thread Starter

ak2011

Joined Oct 24, 2011
12
So i incorporated the current limit....this circuit will limit the current to abt 12A; might do a bit fine tuning, but i think it's good for now

other changes are the voltage reference and op-amp.

what do you think?
 

Attachments

chrisw1990

Joined Oct 22, 2011
551
nice, i assume the transistor is the current limit? i have seen a single transistor current limit before, and used them, very simple! be cheap too
 
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