Abstract

A motor drive for driving two-phase motors using a three-phase bridge output stage, and a method of operating the drive. The driven two-phase motor can be a two-phase bipolar motor (such as a hybrid stepping motor). The drive can also be configured so that a single output stage can be used to drive either two-phase or three-phase motors, with or without a feedback sensor. A reference return is provided from one of the three half-bridge output stages with each of the motor phase windings connected between the reference return and one of the other half-bridge outputs. The switches of each half-bridge are modulated so that current can be controlled in each of the two motor phase windings.