A control circuit for a multi-phase motor (57) comprises a plurality of inverter bridges, a plurality of outputs, and at least one isolation switch (62, 63). Each inverter bridge is arranged to provide an output voltage for a phase of the motor (57). Each output is arranged to be coupled to one phase of the motor (57) to provide the output voltage to that phase of the motor (57). Each isolation switch (62, 63) is coupled between one of the inverter bridges and one of the outputs, so as to selectively isolate the output from the inverter bridge. Each isolation switch (62, 63) comprises a Gallium Nitride (GaN) transistor.