Nice work Jim! Regardless of how useful it is use an East92 as a basis for a custom FET driver (it does look useful, and prettier than a 'nanjg92') I think it is great that you tested the options :-)
Another advantage of using the EAST-92 is that it seems to have a better/more substantial ground ring, so it seems like it’d be more likely to survive being diameter-reduced slightly.
I am curious about one thing: I had to remove and jumper over the diode that goes from Vcc to the capacitor because when I left it in originally, the driver wouldn’t work. I am curious why this might’ve been but also would like to get it to work with the diode as my understanding was that was for reverse voltage protection, which would be nice to retain?
I think that this is the final set of steps I used:
- Remove FET, MCU, voltage divider resistors, and diode above capacitor from driver
- Cut traces to the left and to the right of MCU pin 8 pad
- Cut trace to the left of MCU pin 5 pad
- Solder a wire across MCU pin 8 pad to MCU pin 1 pad to capacitor and also use it to bridge where diode used to be
- Put kapton tape over MCU pin 1 pad (this is to prevent MCU pin 1 connecting to the MCU pin 1 pad)
- Put some solder paste on MCU pads except for pin 1 pad
- Reflow the MCU
- Reflow the FET
- Solder bridge MCU pin 4 to ground ring
- Solder wire between MCU pin 6 and FET Gate pin
Removing the FET (in step #1) is not 100% necessary - it just gives more space when working with the MCU area.
Nice work. I think I might have one or wo of these drivers. Nice to know there is a recipe to update them now available. Thank you.