MP86905 OCP questions

Hi expert,
I’m thinking about how intelli-phase can protect itself in OC and short test.
From your logic, positive current is only sensed from HS FET, negative current is sensed from LS FET, that’s okay but, HS FET will latch off, and report fault# flag after 4 cycles.

  1. If short happens across inductor(or SW to GND), current will ramp as fast as possible, any risk of so much delay for latch off actions & reporting?
  2. If short across SW to VIN, HS FET cannot see any over current, the LS FET will be burnt easily, right?

mps ocp

Hi dickzsh26, welcome to the forum!

The 4 cycle count works adequately to protect the device during an HS FET over current event.

A short from VIN to the SW node will cause no current during the on time, but a large negative current during the off time, which will be caught by the LS-FET during the cycle-by-cycle current limit and cause a hiccup behavior.