Abstract: A motor drive device includes a constant voltage power supply and a motor drive control unit. The constant voltage power supply includes an AC/DC converter, a zero-cross detector, a switching control unit and a switching regulator. The AC/DC converter converts an AC voltage supplied from an AC voltage source into a DC voltage. The zero-cross detector detects a zero-cross point of the AC voltage, and outputs a zero-cross detection signal. The switching control unit outputs a switching control signal based on the zero-cross detection signal. The switching regulator has a switching element. The motor drive control unit outputs a motor drive signal for driving a motor to the inverter. The AC/DC converter has a rectifier circuit and a smoothing capacitor. The switching regulator performs switching on a first DC voltage in accordance with the switching control signal at a timing corresponding to the zero-cross point.

Abstract: A motor driving device includes a microcomputer, a command voltage adjusting circuit, and a driving IC. The command voltage adjusting circuit converts a first command voltage signal from the microcomputer to a second command voltage signal. The driving IC generates a drive pulse based on the second command voltage signal. An upper and a lower limit of an input voltage range of the driving IC are larger than an upper and a lower limit of a voltage range of the first command voltage signal, respectively.

Abstract: A motor drive device includes a constant voltage power supply and a motor drive control unit. The constant voltage power supply includes an AC/DC converter, a zero-cross detector, a switching control unit and a switching regulator. The AC/DC converter converts an AC voltage supplied from an AC voltage source into a DC voltage. The zero-cross detector detects a zero-cross point of the AC voltage, and outputs a zero-cross detection signal. The switching control unit outputs a switching control signal based on the zero-cross detection signal. The switching regulator has a switching element. The motor drive control unit outputs a motor drive signal for driving a motor to the inverter. The AC/DC converter has a rectifier circuit and a smoothing capacitor. The switching regulator performs switching on a first DC voltage in accordance with the switching control signal at a timing corresponding to the zero-cross point.

Abstract: A motor driving device includes a microcomputer, a command voltage adjusting circuit, and a driving IC. The command voltage adjusting circuit converts a first command voltage signal from the microcomputer to a second command voltage signal. The driving IC generates a drive pulse based on the second command voltage signal. An upper and a lower limit of an input voltage range of the driving IC are larger than an upper and a lower limit of a voltage range of the first command voltage signal, respectively.