I am using a LTC4366 to protect a power supply for transients testing with the military, and for the most part is does great. However, one of the test drops the voltage to zero and then applies 50V for x ms and then drops the voltage back to 29V nominal.  Then Repeats.   My power supply has a maximum input of 36V.  This kills the supply, as the 50V gets past the MOSFET which is set to 33V.   Anybody have any ideas.   I realize I can redesign the power supply to handle 50V, but this is already deployed.  Also the power supply pulls about 1.5Amps at 28V.    

  • 0
    •  Analog Employees 
    on Sep 4, 2019 6:31 PM

    Hi, It would help to understand how the 50V gets around the MOSFET if output regulation is set to 33V. One guess is that there is some kind of capacitive coupling (either drain-source or drain-to-gate-to-source) across the MOSFET, especially if the 50V rises quickly. If that's the case, some kind of input capacitance on the supply may help. (Assuming MOSFET BVdss is >50V.)