Guru
Joined: 21/06/2018
Location: AustraliaPosts: 1309
| Posted: 01:46pm 18 Jun 2019 |
You are correct I could use 3 heatsinks but I have chosen one for this assembly.
The ground planes are on both sides of the PCB. Here is the front side of the PCB, all current carrying planes are actually double width (& area) to what you see on one side. The silver areas are just a part of the total area so I could increase current capacity by soldering extra copper conductors where possible.
Due to the fast switching I need ferrites between each drain connection and the external connections, so connecting the drains directly to the heatsinks would not allow that.
If your inveter is working ok I dont advocate to change the gate resistor to 2R2, this suits my fast buffer and PCB layout for fast switching. It may cause other unintended issues to appear on different circuits and layouts.
Using a good fast CRO on the bench when not driving a load is the best way to see the effect of changing the gate resistor values - but it might cause oscillation issues to appear too.
If at first you dont succeed, I suggest you avoid sky diving....
Cheers Mike