公开(公告)号：US10545459B2

公开(公告)日：2020-01-28

申请号：US15754295

申请日：2016-09-09

Applicant: CITIZEN WATCH CO., LTD.

Inventor： Yu Takyoh ,  Toshiaki Fukushima ,  Toshinari Maeda ,  Daisuke Iri ,  Daisuke Matsuoh

IPC: H02P8/02 ,  G04C3/14

Abstract: Provided is a drive circuit for a two-coil stepper motor, including: a rotor; a stator including first, second, and third stator magnetic-pole portions; a coil A to be magnetically coupled to the first stator magnetic-pole portion and the third stator magnetic-pole portion; a coil B to be magnetically coupled to the second stator magnetic-pole portion and the third stator magnetic-pole portion; a drive pulse generation circuit configured to output a drive pulse; a detection pulse generation circuit configured to output a detection pulse for detecting counter-electromotive currents generated in the coil A and the coil B; and a rotation detection circuit configured to receive a detection signal generated due to the detection pulse as input to determine whether or not the rotor has rotated.

公开(公告)号：US11422511B2

公开(公告)日：2022-08-23

申请号：US16914498

申请日：2020-06-29

Applicant: CITIZEN WATCH CO., LTD.

Inventor： Yu Takyoh ,  Toshiaki Fukushima ,  Toshinari Maeda ,  Daisuke Iri ,  Daisuke Matsuoh ,  Masatoshi Nishida

IPC: H02P8/02 ,  G04C3/14 ,  G04C13/11

Abstract: An electronic watch with a two-coil stepper motor including: a magnetized rotor; a stator including: first and second stator magnetic-pole portions, which are formed so as to oppose to each other through the rotor; and a third stator magnetic-pole portion, which is formed between the first stator magnetic-pole portion and the second stator magnetic-pole portion so as to face the rotor; a coil A to be magnetically coupled to the first stator magnetic-pole portion and the third stator magnetic-pole portion; and a coil B to be magnetically coupled to the second stator magnetic-pole portion and the third stator magnetic-pole portion; and a high-speed drive pulse generation circuit configured to output a drive pulse for driving the rotor to the coil A or the coil B, and wherein the rotor is rotationally driven in increments of 360° due to a drive pulse train formed of the plurality of drive pulses.

公开(公告)号：US10754299B2

公开(公告)日：2020-08-25

申请号：US16076690

申请日：2017-02-15

Applicant: CITIZEN WATCH CO., LTD.

Inventor： Yu Takyoh ,  Toshiaki Fukushima ,  Toshinari Maeda ,  Daisuke Iri ,  Daisuke Matsuoh ,  Masatoshi Nishida

IPC: G04C3/14 ,  H02P8/02 ,  G04C13/11

Abstract: An electronic watch with a two-coil stepper motor including: a magnetized rotor; a stator including: first and second stator magnetic-pole portions, which are formed so as to oppose to each other through the rotor; and a third stator magnetic-pole portion, which is formed between the first stator magnetic-pole portion and the second stator magnetic-pole portion so as to face the rotor; a coil A to be magnetically coupled to the first stator magnetic-pole portion and the third stator magnetic-pole portion; and a coil B to be magnetically coupled to the second stator magnetic-pole portion and the third stator magnetic-pole portion; and a high-speed drive pulse generation circuit configured to output a drive pulse for driving the rotor to the coil A or the coil B, and wherein the rotor is rotationally driven in increments of 360° due to a drive pulse train formed of the plurality of drive pulses.

公开(公告)号：US11086273B2

公开(公告)日：2021-08-10

申请号：US16579831

申请日：2019-09-24

Applicant: CITIZEN WATCH CO., LTD.

Inventor： Yu Takyoh ,  Toshiaki Fukushima ,  Toshinari Maeda ,  Daisuke Iri ,  Daisuke Matsuoh

IPC: G04C3/14 ,  H02P8/02 ,  H02P8/16

Abstract: Provided is a drive circuit for a two-coil stepper motor, including: a rotor; a stator including first, second, and third stator magnetic-pole portions; a coil A to be magnetically coupled to the first stator magnetic-pole portion and the third stator magnetic-pole portion; a coil B to be magnetically coupled to the second stator magnetic-pole portion and the third stator magnetic-pole portion; a drive pulse generation circuit configured to output a drive pulse; a detection pulse generation circuit configured to output a detection pulse for detecting counter-electromotive currents generated in the coil A and the coil B; and a rotation detection circuit configured to receive a detection signal generated due to the detection pulse as input to determine whether or not the rotor has rotated.

公开(公告)号：US10197972B2

公开(公告)日：2019-02-05

申请号：US15538658

申请日：2015-12-24

Applicant: CITIZEN WATCH CO., LTD.

Inventor： Toshiaki Fukushima ,  Toshinari Maeda ,  Yu Takyoh ,  Daisuke Iri

IPC: G04C3/14 ,  H02K37/16 ,  H02P8/34 ,  H02P8/02 ,  H02P8/30 ,  H02P6/182

Abstract: Provided is a drive circuit for a two-coil stepper motor, including a rotor that is magnetized to an N-pole and an S-pole, first, second, and third stator magnetic-pole portions, a coil A, and a coil B. The drive circuit includes a drive pulse generation circuit configured to output a drive pulse (SP) for driving the coil A and the coil B, a detection pulse generation circuit configured to output a detection pulse (CP) to the coil A and the coil B in order to detect counter-electromotive currents generated in the coil A and the coil B along with a movement of the rotor after the rotor is driven based on the drive pulse, and a detection circuit configured to receive a detection signal (CS) generated based on the detection pulse as input, to thereby detect the movement of the rotor. At least one of the detection pulse to the coil A or the detection pulse to the coil B is output.

公开(公告)号：US11378920B2

公开(公告)日：2022-07-05

申请号：US17254822

申请日：2019-06-21

Applicant: CITIZEN WATCH CO., LTD.

Inventor： Yu Takyoh

IPC: G04C3/14 ,  H02P6/182 ,  H02P8/02

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.

公开(公告)号：US10331084B2

公开(公告)日：2019-06-25

申请号：US15515515

申请日：2015-09-29

Applicant: CITIZEN WATCH CO., LTD.

Inventor： Daisuke Iri ,  Yu Takyoh

IPC: G04C3/14 ,  H02P8/02

Abstract: An electronic watch includes: a step motor; a driving pulse generator circuit configured to output a driving pulse for driving the step motor; a detection pulse generator circuit configured to output a detection pulse for detecting rotation of the step motor; a correction pulse generator circuit configured to output a correction pulse; a pulse selection circuit configured to select and output the driving pulse, the detection pulse, and the correction pulse; a driver circuit configured to supply to the step motor the outputs from the pulse selection circuit; and a rotation detection circuit configured to receive a detection signal generated by the detection pulse to judge rotation of the step motor. The electronic watch further includes a driving interval switch circuit configured to switch a driving interval of the driving pulse between a normal driving interval and a high-speed driving interval. The rotation detection circuit is capable of changing a detection condition by the driving interval switch circuit.