Hello, I tried to make an full bridge phase shift converter board. My mosfet is SiHR080N60E, Gate driver-ADUM4221-2ARIZ_5,Controller-UC3875_N_2.When I tried my circuit in open loop my circuit behaved correctly and I got the desired output. But when I attempted in closed loop circuit, my gate drivers are failing.

What could be the possible reasons. My guess is miller effect is causing a shoot trough and somehow it is damaging the gate driver. Before failing there is a current surge in the driver supply is it due to miller effect or something else. Interestingly MOSFET are fine but gate drivers keep failing. What are the possible reasons can it be layout related. If someone cold give advice on layout it would be helpful. Will a pull down resistors on all the mosfet help prevent the gate drivers from failing or should i use miller clamp externally.

 

Post schematic and photos of the hardware

 

Post schematic and photos of the hardware

https://forum.allaboutcircuits.com/threads/adum422-isolated-gate-driver-repeatedly-failing.209601/
This is a former thread my friend posted it has all the issues

 

This is a former thread my friend posted it has all the issues

But is your friend's layout identical to yours? Are the components identical?

 

But is your friend's layout identical to yours? Are the components identical?

Apologies for the late reply we both are working on the same project. So it is the same circuit.

 

Hello, I tried to make an full bridge phase shift converter board. My mosfet is SiHR080N60E, Gate driver-ADUM4221-2ARIZ_5,Controller-UC3875_N_2.When I tried my circuit in open loop my circuit behaved correctly and I got the desired output. But when I attempted in closed loop circuit, my gate drivers are failing.

What could be the possible reasons. My guess is miller effect is causing a shoot trough and somehow it is damaging the gate driver. Before failing there is a current surge in the driver supply is it due to miller effect or something else. Interestingly MOSFET are fine but gate drivers keep failing. What are the possible reasons can it be layout related. If someone cold give advice on layout it would be helpful. Will a pull down resistors on all the mosfet help prevent the gate drivers from failing or should i use miller clamp externally.

yes it is because of Miller cap. Especially in no load and phase shifted full bridge it happens. because on the same leg when the higher switch turns on, it clamps teh lower mosfet's drain to high voltage of the bus, and it charges the Cdg of that mosfet which charges the lower's gate and tragedy happens. Use a capacitor from gate to source, it increases the Cgs equivalent and the charge from Cdg wound be enough to move its voltage level. use a cap which makes Cgs/Cdg >5.