I opened my design schematic and realized I had already designed the Vpp control design. So now I have two options. I used an inductor in the first design to filter the base current of the voltage divider. In the second design, I just used an RC low pass filter to filter the base current of the transistor. This project has gone long enough that I am forgetting details of things I have already done.
I prefer the design I did last week to the earlier design. If I find the system doesn’t regulate very well, I may incorporate parts of the earlier design.
Cut in Planning:
Looking at the last schematic and schematic where I want to end up, I can see I need to remove Q4, 5, R6 and R9. I then need to attach pin 1 of the FAN5331 to Pulse. Pin 2 to GND, Pin 3 to Vps. Pin 4 and 5 to the supply side of L1. Short Q4 Pin2 to 3. Finally replace R9 with a transistor with filter to HVPulse.