What is the easiest way to step down from 24V to 20V (20A)?

Thread Starter

Andrius Slizys

Joined Jul 20, 2019
6
Hi guys!

What would be the easiest way to step down 24V power supply to 20V?

I have a power supply 24V, 20A and I would like to get 20V out of it (If it's not too complicated). Power supply on its own has a pot for adjusting voltage for about +/-10%, so actually I could go as low as ~22V. But I need 20V MAX and still be able to pull out 20 amps.

Appreciate any comments.
Cheers, Andrius
 

LesJones

Joined Jan 8, 2017
2,357
You may get away with setting it to 22 volts and adding 3 suitably rated diodes is series with the output. Each diode will drop between 0.6 and 0.7 volts. Weather this meets your needs depends on the nature of the load.

Les.
 

MrChips

Joined Oct 2, 2009
19,397
You may get away with setting it to 22 volts and adding 3 suitably rated diodes is series with the output. Each diode will drop between 0.6 and 0.7 volts. Weather this meets your needs depends on the nature of the load.

Les.
No. The diode forward voltage drop is highly dependent on the diode current.
Also at 4V @ 20A you would need to dissipate 80W.
 

DickCappels

Joined Aug 21, 2008
5,943
Based on the information given, a buck converter would be the best approach. Be prepared to burn a few transistors/MOSFETs and a finger or two, but this will be the most efficient way to make the conversion.

It is basically PWM (Pulse Width Modulation) driving a low pass filter with a control loop around it.

https://en.wikipedia.org/wiki/Buck_converter
 
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