I haven’t found schematics for loneoceans drivers, only the older GXB17 but that’s a more complicated design.
I started by analysing the D4V2.5 linear driver (I posted the schematic on the attiny1 thread), read some app notes about this type of circuit and applied it to a switching converter instead of a mosfet, the opamp inputs just need to be swapped, since with feedback pin on a switching converter, if current goes up, we want FB to go up, instead of down for the gate of a N mosfet.
But it wasn’t stable though (in simulations), something that was super helpful was this schematic of the Convoy XHP35 driver posted by agnelucio, many thanks to him. In which I took the idea of using the feedback voltage divider (R16-R17), the opamp just nudges FB up or down a bit, instead of freely driving it (oscillations hell), which is much more stable, that said I have doubts about the actual stability of the Convoy driver without a compensation capacitor for the op-amp.
I did take a look at pictures posted on loneoceans’ github, it looks to be basically identical (ignoring the dual sense resistor part), also reference for some interesting parts (MIC5019 and TPS706).
I already discussed this with icpart on the lume thread, I don’t think adding another RC stage is useful. At 50% output, where ripple would be the highest (edit : that’s wrong it’s not at 50% that it is the highest :person_facepalming: )
I don’t see any 5kHz ripple.
R=10kΩ, C=470nF, rise time to 90% ~ 10ms