[![If you see this you can get some idea][1]][1] well i also work on a 400V motor driver but I use AMC1300 IC .you want see some details in data sheet . [![get know the connections ][2]][2] here the long story short . **Vin=Ainp-Ainn** INP=0V (Exactly) OP=will give a pulse of 50% duty cycle respect to your frequency. INP=+50mv(Full scale) OP=1 pulse with 89.06% duty cycle (MCU read as "1" ) INP=-50mv(Full Scale) OP=1 pulse with 10.94% duty cycle (MCU read as "0" ) Clipping mode : Only Zeros(pulse width 10.96%) are transmitted if input is ≤ –64 mV. Only Ones (Pulse width 89.06%)are transmitted if input is ≥ +64 mV. so the consolidated answer is consider 0V as a center point If AINP>AINN: Duty cycle is 50% to 89.06% (positive input). If AINN>AINP: Duty cycle is 50% to 10.94% (negative input). your assumption is correct. [1]: https://i.sstatic.net/TMmROHXJ.png [2]: https://i.sstatic.net/Dde6w3o4.png