An axial brushless DC motor comprising a stator including a plurality of coils, a rotor including a magnet with a plurality of pairs of magnetic poles and adapted for movement relative to the stator in one or more full steps, and a coil phase circuit adapted for moving the rotor relative to the stator a fractional step less than the one or more full steps and/or holding the rotor at the fractional or one or more full steps.

An axial brushless DC motor comprising a stator including a plurality of coils, a rotor including a magnet with a plurality of pairs of magnetic poles and adapted for movement relative to the stator in one or more full steps, and a coil phase circuit adapted for moving the rotor relative to the stator a fractional step less than the one or more full steps and/or holding the rotor at the fractional or one or more full steps.

The present invention relates to a driving circuit and a driving method for a stepping motor, and an electronic machine using the same. A current value setting circuit generates a current setting value. A constant current chopper circuit generates a pulse modulation signal, which pulse-width modulates by having a detection value of a coil current flowing through a coil approach close to the current setting value. A logic circuit controls a bridge circuit connected to the coil of the stepping motor according to the pulse modulation signal. The current value setting circuit sets the current setting value to a predetermined full-torque setting value in a first period after rotation starts, reduces the current setting value to a predetermined second setting value less than the first setting value in the following second period, and switches to a high-efficiency mode and adjusts the current setting value by means of feedback control.

The present invention relates to a driving circuit and a driving method for a stepping motor, and an electronic machine using the same. A current value setting circuit generates a current setting value. A constant current chopper circuit generates a pulse modulation signal, which pulse-width modulates by having a detection value of a coil current flowing through a coil approach close to the current setting value. A logic circuit controls a bridge circuit connected to the coil of the stepping motor according to the pulse modulation signal. The current value setting circuit sets the current setting value to a predetermined full-torque setting value in a first period after rotation starts, reduces the current setting value to a predetermined second setting value less than the first setting value in the following second period, and switches to a high-efficiency mode and adjusts the current setting value by means of feedback control.

A motor controller that includes a processing device and a drive circuit. The drive circuit may include a plurality of switches, a motor winding, and a current sensor coupled together in an H-bridge configuration. The processing device is configured to cause a drive current to drive through the motor winding for a minimum amount of time. The processing device is also configured to compare the current through the current sensor to a threshold value at the minimum amount of time. The processing device is also configured to, based on the current being at or above the threshold value at the minimum amount of time, stop the drive current for an off period of time and cause a first decay of the current for a first percentage of the off period of time and a first slow decay for a second percentage of the off period of time.

A motor controller that includes a processing device and a drive circuit. The drive circuit may include a plurality of switches, a motor winding, and a current sensor coupled together in an H-bridge configuration. The processing device is configured to cause a drive current to drive through the motor winding for a minimum amount of time. The processing device is also configured to compare the current through the current sensor to a threshold value at the minimum amount of time. The processing device is also configured to, based on the current being at or above the threshold value at the minimum amount of time, stop the drive current for an off period of time and cause a first decay of the current for a first percentage of the off period of time and a first slow decay for a second percentage of the off period of time.

A vehicle head-up display device includes a stepping motor that outputs a rotation to adjust an optical position of a reflecting mirror, a zero detection unit that detects a zero position by the rotation of the stepping motor in a return-to-zero direction, an initial adjustment unit that adjusts the optical position to an initial position based on the zero position by the rotation of the stepping motor in an away-from-zero direction, and a user adjustment unit that, after the adjustment of the initial position, adjusts the optical position to a command position based on the zero position responsive to a command from the vehicle user. The zero detection unit sets a higher rotation speed of the stepping motor than the user adjustment unit, and sets a lower output torque than the user adjustment unit.

A vehicle head-up display device includes a stepping motor that outputs a rotation to adjust an optical position of a reflecting mirror, a zero detection unit that detects a zero position by the rotation of the stepping motor in a return-to-zero direction, an initial adjustment unit that adjusts the optical position to an initial position based on the zero position by the rotation of the stepping motor in an away-from-zero direction, and a user adjustment unit that, after the adjustment of the initial position, adjusts the optical position to a command position based on the zero position responsive to a command from the vehicle user. The zero detection unit sets a higher rotation speed of the stepping motor than the user adjustment unit, and sets a lower output torque than the user adjustment unit.

According to one embodiment, a controller of a stepping motor includes a table generating unit and a current controlling unit. The table generating unit generates a data table of a threshold by using values of induced voltage at frequencies of switching signal that changes a set value of a drive current, the threshold being proportional to a frequency of the switching signal within an operation region in which the frequency of the switching signal is lower than a predetermined frequency, the values of the induced voltage including a first induced voltage generated at a first frequency of the switching signal and a second induced voltage generated at a second frequency of the switching signal. The current controlling unit controls a value of the drive current in accordance with a comparison result between the threshold and an induced voltage that is detected at a frequency lower than the predetermined frequency.

According to one embodiment, a controller of a stepping motor includes a table generating unit and a current controlling unit. The table generating unit generates a data table of a threshold by using values of induced voltage at frequencies of switching signal that changes a set value of a drive current, the threshold being proportional to a frequency of the switching signal within an operation region in which the frequency of the switching signal is lower than a predetermined frequency, the values of the induced voltage including a first induced voltage generated at a first frequency of the switching signal and a second induced voltage generated at a second frequency of the switching signal. The current controlling unit controls a value of the drive current in accordance with a comparison result between the threshold and an induced voltage that is detected at a frequency lower than the predetermined frequency.