Seiko Epson Corporation

Tomoki Okuhata

Reiko Nagahama

A stepping motor, a driver, a current detection circuit, a first driving circuit configured to output a first driving signal to the driver, a rotation detection circuit configured to detect rotation of the rotor, and a second driving circuit configured to output a second driving signal selected from plural kinds of the second driving signals with different supply times of the driving current supplied to the coil, and configured to output a correction driving pulse that is preset to the driver when, after outputting the second driving signal, the rotation detection circuit detects that the rotor is not rotating, are included, and a resistance value R[Ω] of the coil and the driving voltage V volts of the stepping motor satisfy 900×V[Ω]≤R[Ω]≤1100×V[Ω], and 1.8 volts≤V≤2.4 volts.

Movement and electronic watch

An electronic watch includes a driver controlled to be in an ON state in which a drive current is supplied to a coil of a motor and an OFF state in which the drive current is not supplied to the coil, a target current value setter configured to set a target current value in accordance with a drive voltage for driving the motor, and a driver controller configured to compare a detected current value of a current flowing to the coil with the target current value, control the driver to be in the ON state or the OFF state in accordance with a result of the comparison, and switch polarity of the drive current when detecting that an ON time, which is a duration of the ON state of the driver, meets a predetermined condition or an OFF time, which is a duration of the OFF state of the driver, meets a predetermined condition.

Electronic watch, motor control circuit, and method for controlling electronic watch

An electronic timepiece enables driving a motor in a reverse direction. The timepiece has a current detector detecting a current value flowing through a coil; a driver controller that outputs, according to the detected current value, a first drive signal turning the rotor in a forward direction to a position not pulled to a second statically stable position from a position where the rotor is pulled to a first statically stable position, outputs a second drive signal turning the rotor in a reverse direction past the dynamically stable position after outputting the first drive signal, and outputs a third drive signal turning the rotor in the reverse direction after outputting the second drive signal; and a driver that is controlled according to the first, second and third drive signals to an on state supplying drive current to the coil and an off state not supplying drive current to the coil.

Growing community of inventors

Shiojiri, Japan

Tomoki Okuhata