* Please clarify: Is ground connection at the join of three motor windings? It appears to be star (wye) arrangement.
* High side transistors do not turn on fully unless they receive sufficient bias voltage. In other words, greater than Vbat. Does the IC produce this (for instance via bootstrap circuit)?
* When the motor turns on, expect it to pull down supply voltage as it draws startup surge. It may affect your control IC (since it no doubt requires stable supply voltage). Therefore it's a good idea to have two power converters, one for the control IC, one for the motor.