Re: Chaining power supplies together.

Harvey White

Overvoltage would take a zener, or an SCR/zener trigger (IMHO).

A straight back biased diode (say 3 amps at 100 volts or so) should take care of back biasing the power supply.   (reverse polarity here).  It does not protect against positive current being driven into the supply's outputs.

The problem with charging a battery is that the output is lower than the battery voltage, so current flows the wrong way.  PUtting a series diode between the supply and battery (say 50 to 100 PIV) and rated for more than the PS current, would protect the supply You'd have to figure in that your output voltage is 1 diode drop lower than the supply voltage, except that for batter charging, you *may* be more concerned with the current, not the voltage.

While you may be able to play games with the sense inputs, I have no idea of the internal wiring, and don't know (based on no schematic how the circuit might behave).

This is for trying to constant current charge a battery, though.


On 5/1/2021 6:10 PM, Dave Peterson via wrote:
So by protection diode, you're not talking about over-voltage, you're talking about accidentally driving another source. So a forward biased diode that would prevent current into the power supply.

That much I got. No, don't drive into the PS, either setup in parallel, or attempting to drive some other source. Yeah, I wouldn't do that. (On purpose).


On Saturday, May 1, 2021, 02:52:35 PM PDT, Harvey White <> wrote:
Definitely.  Most power supplies take a very dim (as in permanently off)
view of reverse voltage applied to their terminals.  Most also don't
like to be tied to another power supply in parallel unless designed for it.

If you're going to charge a battery with a Chinese (or many other types)
power supply, put a series diode in so that the supply can't be fed by
the battery.


On 5/1/2021 5:38 PM, Ed Breya via wrote:
Be sure to add an external reverse protection diode across each output, in case there isn't one built in.


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