Motor drive control device, motor unit, and motor drive control method

A motor drive control method for controlling driving of a two-phase stepping motor by a motor drive control device, the motor drive control method comprising:

• a first step of generating, by the motor drive control device, a control signal for controlling driving of the two-phase stepping motor such that one-phase excitation of exciting, of coils of two phases of the two-phase stepping motor, a coil for one phase, and two-phase excitation of exciting, of the coils of two phases, the coils for two phases are alternately repeated;
• and
• a second step of driving, by the motor drive control device, the coils of two phases based on the control signal, wherein
• an energization angle representing a magnitude of an electric angle for continuously energizing the coil of one phase in one direction is set in the motor drive control device, and
• the first step includes
• a third step of determining a period for performing the one-phase excitation based on a back electromotive voltage generated in the coil non-excited in the one-phase excitation, and
• a fourth step of determining a period for performing the two-phase excitation based on an elapsed time per unit angle while the two-phase stepping motor is being excited and the energization angle.