Motor driving device

A motor driving device for driving a motor having a plurality of coil sets, comprising:

• a plurality of energization systems each including a drive circuit, the plurality of drive circuits being one-to-one connected to the plurality of coil sets;
• a plurality of first semiconductor switches disposed in the plurality of energization systems in a one-to-one correspondence, each first semiconductor switch lying between a power supply and a corresponding one of the plurality of drive circuits;
• a second semiconductor switch which connects the power supply and each of the plurality of first semiconductor switches in series;
• and
• a controller connected to the plurality of drive circuits and the first and second semiconductor switches so as to control the plurality of drive circuits and the first and second semiconductor switches, wherein
• each of the plurality of first semiconductor switches includes a parasitic diode of which a forward direction is from a corresponding one of the drive circuits to the second semiconductor switch, and
• the second semiconductor switch includes a parasitic diode of which a forward direction is from the power supply to the first semiconductor switches.