The driver is controlled via two input pins, one for turning power ON/OFF, and another for selecting direction CW/CCW. When turned ON, the control driver converts the motor supply voltage Vs of up to +5V into two square wave signals at around 45 kHz, shifted 90 degrees.
Two transformers step up the voltages to around 200Vrms before being applied to the motor. It is the phase shift that makes the waves on the stator wandering instead of standing.