Differential transceiver SN65C1167
Yes, you really do need a differential PWM signal if you want to use the differential pins (inputs 3-10) on the CGD1200HB2P-BM2.
The Threshold voltage is shown in the Gate Driver Electrical Characterization:

You need to have a differential voltage below -200mV and above -7V in order for the 0 to be detected.