I have a DRV8840 that I am trying to use. I have burned up about 10 of them trying to get it working.
For this application, I need the H-Bridge to Current Limit and Brake the motor. Max current draw can be no more than 2A and it needs to stop very quickly
I have gone through a couple revisions, but always the H-Bridge blows up.
Here are the motor details:
24V 2A drawn Brake enabled (called slow decay in the datasheet)
The voltage applied to this motor flips polarity, so I have a diode bridge in between imcoming power and the H-Bridge
Here is my schematic
Brown and white is incoming power to feed the H-Bridge. Brown and white switch polarity and the diodes prevent the H-Bridge itself from having a reverse polarity applied
Red and Yellow are the motor outputs
Some notes on the diodes:
(I'm new to eagle and didn't really know how to create new components)
D1-D4 = Schottky Diodes (I used these for less forward voltage drop)
I don't use the built in 3.3V voltage regulator but instead use a voltage divider and use the reference implentation on page 8 of the DRV8840 datasheet
Again, the only reason I need the H-Bridge is to brake the motor and to limit the current. Maybe I am going about this the wrong way, but I still do not understand why the H-Bridge dies so fast. Thanks for your help!