The ramp generator on its own board. It feeds the buck stage and does not replace it. It is pure analog, a capacitor-charging ramp set by precision comparators, with no microcontroller. Three sections (trigger generator, analog ramp, PWM converter) give independently adjustable ramp-up (3-60 ms) and ramp-down (300 μs-6 ms), plus a ‘starburst’ mode up to 3× steeper than the fastest plain ramp. Shared as through-hole Gerbers and a BOM for a 4-layer board. A fellow forum member built a Digikey cart for it within days. The breadboard prototype pictured has a hand-labelled knob for every parameter.
Schematics and photos
schematic: “Analog Ramp Generator for QCW”, Benjamin Lockhart, rev v1.5 (KiCad 9, 11 Sep 2026)
Sources
This is the card from the driver tree, written from what the builder published. Send corrections through the forum.