Dear readers,
I’m designing a small 5V SMPS which I want to use in a 5V parallel configuration. I want to use ORing Diodes but these give me a drop of 0,2…0.4 Volt. So I came up with and better solution, but I don’t have experience with this one.
Below you see two buck converters. In SMPS[A] I have put the ORing diode in series with the output and in SMPS I have put the ORing diode before the FB resistor network. SMPS does not suffer from the 0.2…0.4 voltage drop. However in case the input voltage of B is zero the FB pin will have a voltage of around the FB voltage of 0.8V.
Assuming that both SMPS[A] and have input power the the combinations A-A A-B and B-B should work without a problem.
Assuming that SMPS[A] has input power SMPS has no power and is switched on after some time. The combinations A-A B-B will work but combination A-B I have my doubts about.
If B is powerless and has 0.8V at it’s feedback pin and ten starts up will that not generate trouble like latch up or some other issues I’m not aware of.
Now my question: does anyone have experience with this and can tell me if there are things I need to consider.
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