I tried to evaluate the OVP function of MP8030 but found something strange.
According to the absolute maximum value of the datasheet, I assume that fault voltage under 100V should not damage MP8030 and select DC 75V as the test voltage.
During the test, 75VDC was applied to EVL8030-QJ-00B through a passive PoE injector, and I can see it entering hiccup mode which is mentioned in the datasheet.
However, when I removed 75VDC and re-powering at 56VDC, DC input was pulled down.
The strange thing is that I can’t measure any shortage on EVL8030-QJ-00B, and when I replace the passive PoE injector with a standard PSE switch, EVL8030-QJ-00B seems to work fine.
Please help check if I tested it the wrong way.
Thanks.
Hello aiolus7,
This is what is provided in the EVL8030 datasheet for the startup procedure.
Would you be able to share captures that depict the behavior you are talking about?
Hello,
Instead of connecting your supply through that cable can you try connecting your supply directly to the board through Vdd and Vss?
I’m checking the bridge circuit today and found 2 of SI2392 breakdowns, so I replaced all SI2392 with similar 3A MOSFET, and EV board back to work.
Then, I test it with 75VDC and everything looks fine.
However, when increasing the voltage to 85VDC, EV board is short.
After checking, SMAJ58A the TVS is short, so I removed it and went back to see if EV board was damaged. Unfortunately, there is no 12V output, and the waveform was captured as attached.(VDD was pulled down periodically)
Again, I try to input with DC power supply, and this time EV board was burned.
