We have designed the DRV8844 as High Side / Low Side driver in a 48V application. One of the requirements is Output connected to battery while the unit is not powered. When we apply +48V power (12.5A max power supply) to one of its outputs while the unit is not powered, the part is blowing up. See attached picture. It blew up instantly as the 48V is connected to the output.
I think this is due to high inrush current charging the VM bulk capacitor, in our case we have 33uF. See attached schematic. The intrinsic freewheeling diode of the output to VM is what I believe that is getting damaged.
I tried it at 12V power source, it did not damage the part and the power supply current seems to be at around 20mA. Then I used a current limited (3A max) 48V power supply, it didn't damaged the part either. But when I used the 48V 12.5A power supply, it blew up a second unit.
What can we do to prevent such catastrophic failures?
