I completed our SMPS design using the PI expert Tool for a single phase applicaiton, which is presently working fine with out end product (energy meters), and tested to be okay. See schematic attached (MMXPLC-PSU-1203-1203)
However, I tried to implement same for the our three phase applicaiton, by altering only the rectifyfing diodes up towards the mains supply, to accomodate the three phase input (see attached - MMXPLC006_PSU_SCH_v01), but the 2 caps C4 and C5, got exploded.
Designed input range: 100 - 240VAC.
I previously, tested the three phase SMPS by paralleling all three phases and connecting to a single input source, and its okay...I got my outputs with the end device powered and working. I then thought all was okay.
But when I connected to an ideal three phase....there was a BANG! I had to replace the caps, and D18 at the second output for me to get it back working.
I tested, and observed, that at 180VAC to applied to each of the phases, there was about 430VDC rectified DC, which justified the burst-up at 220VAC.
I just read about the StackFET design, which was not implemented in my design. Could this be the problelm?
If it is, can I be guided on the steps to take to implement the StackFET into this design.
if it was not the cause, then how can I figure out the problem?