AC Coupling Analog-to-PWM Converter

[Evan.Cornell]

I am trying to implement simulation of TI's app note SLAU508 - Analog Pulse Width Modulation (https://www.ti.com/lit/ug/slau508/slau508.pdf), but modifying it for ac-coupled input to avoid having any DC offsets that would cause problems when driving a full-bridge power stage.

I removed R2 from the circuit, per app note, but then the output only generates PWM output on the negative-going half of the input sinewave. It seems the signal on the error-amplifier side of the ac coupling cap is now biased around VCC instead of VCC/2 (VREF). Does anyone know how else can I modify the circuit to enable proper ac-coupling of the input signal?

FYI - cross-posted on TI's e2e forum.

[MasterT]

Do not remove R2 . Set s cap in series with input (R3). Value C depends on frequency of operation

[Evan.Cornell]

I may have had a simulation error previously. I just checked now, and doing what the app note said, remove R2, works fine.