# Using multiple voltage converters from one source - diodes needed?

#### RogueRose

Joined Oct 10, 2014
375
I have 5 180 watt voltage converters that put out 5-36v and the input is something similar in V, but I'm using a transformer (rectified with smoothing cap) that puts out 23.5-24vdc, it is possible to get 18, 19, 20, 21, 22v from it as well as I have tapped into some windings but the using the whole winding I get ~24v. I've run it at about 50 amps (it was a 1500 watt HID transformer) which is about 1200 watts. The most these converters will use is about 900, so I have ample power supply.

I need the converters to put out 21 - 25v (depends on what I'm doing with it) and occasionally 33v . They are all running seperately (each converter has a seperate isolated load, like a battery pack, motor, or electrolysis cell) but are going to be fed from the same transformer output.

I am wondering if I need to put some diodes and or switches in place between the transformer output and the converters. I've been using screw down terminals (one side is all parallel with transformer output) and then a wire attached at each terminal for each converter. The same is done for both the positive and negative sides of the transformer output.

So, are diodes necessary and would a switch be necessary (if a good idea, I'll add later, but  is tight ATM).

Joined Feb 20, 2016
3,316
If you are just running a number of switch mode regulators, I think that is what you are referring to, it does depend on their circuitry.
But most have a common 0V between input and output, so you can just run them off the same supply.

Unless the loads need to be isolated from each other, then you really need a separate winding for each supply. Diode isolation will not suffice in that case. And if you need to run the supplies in series too. Then isolated windings are used.

#### MisterBill2

Joined Jan 23, 2018
5,188
There are both isolated and non-isolated power converters. If yours are isolated then there is no need for diodes, If they are non-isolated, then the possible issue would be if the output of one converter contacted the output of another converter. The drawing in post#2 shows nin-isolated converters, as an example.