A novel motor controller controls a stepping motor and includes a command value calculator to calculate and output a speed command value and an angle command value based on a reference clock. A control method selector is included to select one of the open-loop control and the closed-loop control in accordance with the speed command value. A command value output unit is included to output a first target value as the first current command value when the open-loop control is selected and outputs a second target value as the second current command value when the closed-loop control is selected. The motor controller controls the stepping motor based on the first target value when the open-loop control is selected and the second target value when the closed-loop control is selected.

A control circuit includes a storage unit, a generation unit, an update unit, and a rotation control unit. The storage unit stores a predetermined number of register values to designate a step frequency of a stepper motor. The generation unit generates a micro step clock signal every time a period corresponding to each of the predetermined number of register values stored in the storage unit elapses. The update unit updates the predetermined number of register values stored in the storage unit every time the generation unit generates the predetermined number of micro step clock signals. The rotation control unit supplies a phase current based on the micro step clock signal generated by the generation unit to the stepper motor to rotate a rotor of the stepper motor by a micro step angle found by equally dividing a step angle of the stepper motor into the predetermined number.

A control circuit includes a storage unit, a generation unit, an update unit, and a rotation control unit. The storage unit stores a predetermined number of register values to designate a step frequency of a stepper motor. The generation unit generates a micro step clock signal every time a period corresponding to each of the predetermined number of register values stored in the storage unit elapses. The update unit updates the predetermined number of register values stored in the storage unit every time the generation unit generates the predetermined number of micro step clock signals. The rotation control unit supplies a phase current based on the micro step clock signal generated by the generation unit to the stepper motor to rotate a rotor of the stepper motor by a micro step angle found by equally dividing a step angle of the stepper motor into the predetermined number.

The present disclosure provides a motor drive device. The motor drive device includes a current detection unit, a control unit and a determination unit. The current detection unit detects a current flowing through a motor coil. The control unit executes a slow attenuation mode that attenuates the current after an end of a power supply mode. The determination unit determines whether the current at a second time point while a predetermined time has elapsed from a first time point when the power supply mode is switched to a slow decay mode is below a limit value. When the determination unit determines that the current does not fall below the limit value, the control unit is configured to switch from the slow attenuation mode to a fast attenuation mode at the second time point.

The present disclosure provides a motor drive device. The motor drive device includes a current detection unit, a control unit and a determination unit. The current detection unit detects a current flowing through a motor coil. The control unit executes a slow attenuation mode that attenuates the current after an end of a power supply mode. The determination unit determines whether the current at a second time point while a predetermined time has elapsed from a first time point when the power supply mode is switched to a slow decay mode is below a limit value. When the determination unit determines that the current does not fall below the limit value, the control unit is configured to switch from the slow attenuation mode to a fast attenuation mode at the second time point.

A motor control device according to an embodiment comprises a first signal generator, a second signal generator, a main controller, and a driver. The first signal generator is configured to generate, based on a clock signal indicating a stepping drive cycle of a motor, a first control signal. The second signal generator is configured to generate, based on a command phase indicating a target phase of a rotor of the motor, a second control signal. The main controller is configured to control the first signal generator and the second signal generator to output at least one of the first control signal and the second control signal. The driver is configured to drive the motor based on at least one of the first control signal and the second control signal.

A stepping motor control device is provided, which controls a stepping motor including a rotor position detector by micro-step driving. The control device has a plurality of operation modes including an adjustment mode and a use mode. In the adjustment mode, the control device generates control data for a closed loop control for controlling the winding current of the stepping motor based on the detection value of the rotor position detector, and performs a stepping motor acceleration operation and a stepping motor deceleration operation according to the control data. In the use mode, the control device performs the stepping motor acceleration operation and the stepping motor deceleration operation so that a winding current observed in the adjustment mode is reproduced by an open loop control for controlling the winding current of the stepping motor based on the control data generated in the adjustment mode.

A stepping motor control device is provided, which controls a stepping motor including a rotor position detector by micro-step driving. The control device has a plurality of operation modes including an adjustment mode and a use mode. In the adjustment mode, the control device generates control data for a closed loop control for controlling the winding current of the stepping motor based on the detection value of the rotor position detector, and performs a stepping motor acceleration operation and a stepping motor deceleration operation according to the control data. In the use mode, the control device performs the stepping motor acceleration operation and the stepping motor deceleration operation so that a winding current observed in the adjustment mode is reproduced by an open loop control for controlling the winding current of the stepping motor based on the control data generated in the adjustment mode.

A current state determination method is configured to determine a state of current passing through a coil of a motor and includes: at a first time point when a high side transistor and a low side transistor are switched to a cut-off state, measuring a voltage of a node where the high side transistor, the low side transistor and the coil are coupled, so as to output a first voltage; at a second time point when the high side transistor and the low side transistor are maintained in the cut-off state, measuring the voltage of the node, so as to output a second voltage; comparing the first voltage and the second voltage to obtain a comparison result; and determining the state of the current according to the comparison result. The present disclosure also provides a current state determination circuit for performing the current state determination method.

A current state determination method is configured to determine a state of current passing through a coil of a motor and includes: at a first time point when a high side transistor and a low side transistor are switched to a cut-off state, measuring a voltage of a node where the high side transistor, the low side transistor and the coil are coupled, so as to output a first voltage; at a second time point when the high side transistor and the low side transistor are maintained in the cut-off state, measuring the voltage of the node, so as to output a second voltage; comparing the first voltage and the second voltage to obtain a comparison result; and determining the state of the current according to the comparison result. The present disclosure also provides a current state determination circuit for performing the current state determination method.