>>2925706
> I’d personally limit the low frequency gain to 40-60dB, and limit the high-frequency gain to 20dB or so, but open-loop low-frequency gain might be acceptable. Either way you’ll want to make U3A and U3B into symmetric differential amplifiers, with the same components on both their inverting and non-inverting inputs.
i understand your point about open loop being unstable but i'm having trouble following this due to knowledge gaps. why differential? wouldn't my differential input just be in reference to ground? do you mean something like pic related?
>Also R14/R15 is probably a wrong ratio,
it's for a single cell battery charger. i want to do NiMH and 18650s, so my voltages of interest are 1.5V and 4.2V. i figured division by 2 would be adequate given my 3.3V supply rail.
>you’ve inverted the feedback lines with U3A and U3B compared to a normal converter with no op-amps
i'm not following this. are you saying i need to flip non inverting and inverting pins? i looked at TI's TL103WB and they put the reference voltage on the non-inverting pin and the sensed voltage on the inverting pin.
>And 330Ω looks kinda low.
xl4015 doesnt listen the FB bias current... but yeah, i could probably go with 3.3K.