An apparatus for treating a respiratory disorder in a patient includes a power supply, a first power supply circuit coupled to the power supply, a pressure generator to generate a flow of air, a transducer to generate a flow signal representing a property of the flow of air, and motor power supply circuitry. The motor power supply circuitry includes: a motor controller to control operation of a motor in the pressure generator based on the flow signal; one or more storage elements to store energy generated by motor deceleration; an energy dissipation circuit to dissipate a portion the energy generated by the deceleration of the motor; and an energy transfer circuit to couple the one or more storage elements to the first power supply circuit and transfer the energy generated by motor deceleration and/or the energy stored by the one or more storage elements to the first power supply circuit.