Method and apparatus for driving an electric motor

A method of driving a motor drive apparatus having first, second and third half bridge circuits, each of said first, second and third half bridge circuits having a first transistor which is adapted to form a first current path between a first operating potential and an output terminal thereof and a second transistor which is adapted to form a second current path between a second operating potential and the output terminal thereof, wherein each of the output terminals is connected to a corresponding drive coil of a motor and wherein each of said first and second transistors has a control terminal to which a control signal is supplied, said method comprising the steps of:

• a first step for detecting a counter-induced voltage of said drive coil corresponding to said second half bridge circuit by supplying control signals to said second transistor of said first bridge circuit, to said first and second transistors of said second half bridle circuit and to said first transistor of said third half bridge circuit for cutting off the second current path in said second transistor of said first bridge circuit, the first and second current paths in said first and second transistors, respectively, of said second half bridge circuit and the first current path in said first transistor of said third half bridge circuit, and by supplying control signals to said first transistor of said first half bridge circuit and to said second transistor of said third half bridge circuit for forming the first current path in said first transistor of said first half bridge circuit and the second current path in said second transistor of said third half bridge circuit respectively, and
• a second step for cutting off the first current path in said first transistor of said first half bridge circuit, for forming the first current path in said first transistor of said first half bridge circuit and for cutting off again the first current path in said first transistor of said first half bridge circuit by supplying control signals to said first transistor of said first half bridge circuit after start of supplying a control signal to said first transistor in said second half bridge circuit for forming the first current path in said first transistor of said second half bridge circuit, wherein a control signal for forming the second current path in said second transistor of said third half bridge circuit is supplied to the control terminal of said second transistor of said third half bridge circuit.