Would this work.

Thread Starter

thedoc8

Joined Nov 28, 2012
162
Bought a buck converter, cc,cv. Just for fun I want to remove the fet and solder short wires out to a more heavy duty fet on a bigger heat sync plus do the same with a heavier Schottky diode. I could just buy a bigger one, but love the control system on this one. Only look to increase an amp or two, mostly to increase the heat dissipation with the heavier fet. Would I need to increase the inductor for a few more amps. Would I keep the same value and just get one with larger wingdings. Any comments.. thanks.
 

Alec_t

Joined Sep 17, 2013
15,119
Extending the wires could result in spurious oscillation of the FET. Be prepared to have to find a way to suppress that, perhaps with a judiciously placed ferite bead or two.
 

BobTPH

Joined Jun 5, 2013
11,515
The inductor would almost certainly need to be upgraded to one that would not saturate at the higher current, and would not overheat. If you look at datasheets for DC to DC converter chips, the layout is critical with very short paths required for the high current connections. I don't think it would work with a larger MOSFET taken off the board even if you did upgrade all the needed components. Start with a chip and go through the whole design process if you want a higher current.

Bob
 

crutschow

Joined Mar 14, 2008
38,507
If the leads were no more than an inch or so you could probably get by with adding a larger MOSFET.
If the MOSFET has a sufficiently low ON resistance you may not need a heatsink.
But you would also have to make the other changes noted, such as a larger inductor.
 

ian field

Joined Oct 27, 2012
6,536
Extending the wires could result in spurious oscillation of the FET. Be prepared to have to find a way to suppress that, perhaps with a judiciously placed ferite bead or two.
And suddenly not all the on current will be building flux lines around the main inductor.

Shorter those wires the better.
 
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