A timepiece includes a determination unit configured to execute determination processing of determining whether a braking force that brakes a rotor is preferably large or small, the rotor being rotated in a normal rotation direction to rotate a pointer clockwise; and a detection control unit configured to cause execution of rotation detection processing of detecting rotation of the rotor based on a first induced voltage output to a predetermined terminal among the first terminal and the second terminal being connected to a coil configured to generate a magnetic flux to rotate the rotor in the normal rotation direction, the predetermined terminal being selected based on the determination by the determination unit.

A watch includes a chargeable power supply, a crystal oscillation circuit including a crystal oscillator and an oscillation circuit and configured to stop oscillating when a power supply voltage falls below an oscillation stop voltage and to start oscillating when the power supply voltage exceeds an oscillation start voltage, which is higher than the oscillation stop voltage, and a divider circuit that outputs a reference signal by dividing an oscillation signal output from the oscillation circuit. The watch also includes a temperature compensation circuit that performs a temperature compensation function operation that compensates for variation of the reference signal due to a temperature, a first voltage detection circuit that detects that the power supply voltage exceeded a first voltage that is set higher than the oscillation start voltage, and a control circuit that starts the temperature compensation function operation of the temperature compensation circuit when the first voltage detection circuit detects that the power supply voltage exceeded the first voltage, and subsequently continues the temperature compensation function operation even when the power supply voltage falls below the first voltage.

A stepping motor control device is configured to drive a stepping motor by applying a normal drive pulse or a fixed pulse having an energy larger than that of the normal drive pulse. The stepping motor control device includes a determination unit configured to, based on whether or not a pulse applied to the stepping motor before the normal drive pulse is the fixed pulse, determine whether or not to add a degaussing pulse is applied to the normal drive pulse, the degaussing pulse being a pulse for canceling a residual magnetic flux generated in a stator of the stepping motor when the fixed pulse; and a drive control unit configured to, based on a determination result of the determination unit, drive the stepping motor with the normal drive pulse to which the degaussing pulse is added.

There is provided an analog electronic timepiece including a stepping motor in which a rotor magnetized in two poles is rotationally driven in a stator connected to a driving coil, a drive circuit for applying a drive pulse to the driving coil, the drive pulse being a pulse for driving the rotor, and a control unit for controlling application of the drive pulse by the drive circuit, in which when an induced voltage induced in the driving coil by rotation of the rotor satisfies a predetermined condition related to the induced voltage, the control unit controls the drive circuit so that the drive pulse is applied to the driving coil before free vibration of the rotor is settled.

An electronic timepiece detects an external magnetic field without using a magnetic sensor. The electronic timepiece has a driver that drives a motor; a current detector that detects a current value flowing through a coil of the motor; a controller that controls the driver to the on state or the off state according to the detected current value; a polarity changer that alternately changes the polarity of the drive current to a first polarity and a second polarity when an on time, which is a continuous time of the on state, meets a specific condition; a counter that counts the number of on states in the first polarity and the number of on states in the second polarity; and an external magnetic field detector that detects an external magnetic field based on a result of comparing the counted number of on states in the first polarity and the second polarity.

A step motor drive device includes a step motor including a rotor, stators, and a coil, a drive circuit that outputs a drive signal including a plurality of partial signals that are output intermittently, a detecting circuit that detects an electromagnetic induced current that is generated in the coil after the partial signals are output, and a control unit that controls the drive circuit. The drive circuit outputs one of the partial signals included in the drive signal to the coil, and, in response to a change in an electromagnetic induced current generated in the coil after the partial signal is output, outputs a next partial signal to the coil. The control unit determines a control method of the step motor based on an interval of the plurality of partial signals, and controls the drive circuit based on the determined control method.

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.

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.

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.

An electronic watch includes a motor including a coil, a driver controlled to an ON state for supplying a driving current to the coil and an OFF state for not supplying the driving current, a driver controller configured to control the driver to the ON state or the OFF state depending on a value of a current flowing through the coil, and a polarity switcher configured to switch a polarity of the driving current when a prescribed condition is satisfied after detecting that an ON time, which is a duration of the ON state of the driver controller, reaches a maximum.