Uploaded November 2024 | Updated September 2026, 2 weeks ago
Driving a 650V SiC fet with the IXDD630 + SN74LV4046A for PLL feedback using a CT. It's a lazy mans approach with only the single drive stage using an IC and the final SiC fet power stage.
The SiC is made to be able to take +15V/0V gate drive. My first run of this circuit at about 43V max was switching a little differently but it was still running cool at about 250W. I just didn't trust running it much over 40V. I have a single tiny 1nF cap on the drain of this fet and if I recall it had a lot more gate charge and drain capacitance than I anticipated. Maybe double that of the ones I'm going to start using. For that reason I decided to leave this at 4.5Mhz and just call it done after switching to 15V gate drive. While this can be a more complicated approach than the self oscillating circuits I find it to be more resilient and I can play around a little with the tuning at over 40VDC without worrying too much. I hit about 300V on the drain with 50VDC input. To keep the voltage down to about 60VDC or under I could try playing with the coupling to see if it could hit about 400W or more at that 60V.
Driving a 650V SiC fet with the IXDD630 + SN74LV4046A for PLL feedback using a CT. It's a lazy mans approach with only the single drive stage using an IC and the final SiC fet power stage.
The SiC is made to be able to take +15V/0V gate drive. My first run of this circuit at about 43V max was switching a little differently but it was still running cool at about 250W. I just didn't trust running it much over 40V. I have a single tiny 1nF cap on the drain of this fet and if I recall it had a lot more gate charge and drain capacitance than I anticipated. Maybe double that of the ones I'm going to start using. For that reason I decided to leave this at 4.5Mhz and just call it done after switching to 15V gate drive. While this can be a more complicated approach than the self oscillating circuits I find it to be more resilient and I can play around a little with the tuning at over 40VDC without worrying too much. I hit about 300V on the drain with 50VDC input. To keep the voltage down to about 60VDC or under I could try playing with the coupling to see if it could hit about 400W or more at that 60V.
