I have a DC/DC converter that gives 3.3 V output.In our system it is the most important part.So we need a redundancy for this.So that if one of the converter fails the other should automatically get switched on. What kind of circuitry do we need to get this kind of logic.
Redundant systems would typically employ an ORing-FET as shown below (source):
The idea is that redundant DC-DC converters supply the required voltage in a current sharing configuration so that both converters supply equal current and therefore have (pretty much) equal thermal stress.
In a fault situation the ORing FET isolates the problematic converter and the other one takes over.
How about this? I have made some presumptions:
- The load is a general digital circuitry that doesn't draw insane amount of Amps
- The converter always fails Open-Circuit - blow-thru causing input voltage to appear at the load is not detected
- The load would be happy with 3.3V - Vf of D1
You will need to provide some additional info, otherwise we can only guess.