Step motor driving device
AssigneeCitizen Watch Co., Ltd.
InventorYu Takyoh
Life of this patent
Estimating the term…
Abstract
To reliably rotate a step motor while reducing power consumption, a step motor driving device includes a step motor that includes a rotor, stator, coil, driver circuit that outputs a measurement drive signal to the coil, phase detecting circuit that detects a counter-electromotive current that is generated in the coil after the output of the measurement drive signal and determines whether a phase of the rotor is a desired phase based on the detected counter-electromotive current, and a control unit that, if the phase is the desired phase, controls the step motor by a first driving method in which the drive circuit outputs a first drive signal for rotating the rotor by one step, and, if not, controls the step motor by a second driving method different from the first driving method so as to restrict the rotation of the rotor.
Claims12
A step motor driving device comprising:
- a step motor that includes a rotor that is magnetized by two or more poles, a stator that transmits a magnetic force to the rotor and a coil that generates a magnetic force toward the stator;
- a drive circuit that outputs a measurement drive signal to the coil;
- a phase detecting circuit that detects a counter-electromotive current that occurs in the coil after the output of the measurement drive signal, and determines whether a phase of the rotor is a first phase based on the detected counter-electromotive current;
- and
- a control unit that controls the step motor by a first driving method, in which the drive circuit outputs a first drive signal for rotating the rotor by one step, when the phase of the rotor is the first phase, and controls the step motor by a second driving method different from the first driving method so as to restrict the rotation of the rotor when the phase is not the first phase of the rotor.
Dependencies are inferred from the claim text.