Kabushiki Kaisha Daini Seikosha

Akira Torisawa

Masaharu Shida

Makoto Ueda

Masaaki Mandai

Kazuhiro Asano

Katsuhiko Sato

Katsuhiko Satoh

Shuji Otawa

Shuji Owada

Jun Ueda

A driver circuit for a stepping motor having a coil, a stator and a rotor receives pulse signals from a pulse signal generator to rotationally drive the rotor. A rotation detection circuit comprises switching circuitry switchable between a high impedance loop formed of the coil and a high impedance element and a low impedance loop formed of the coil and a low impedance element, and means for detecting the voltage induced in the coil. After a pulse signal is applied to the stepping motor, the switching circuitry forms the high impedance loop and the detecting means compares the voltage developed across the high impedance element with a predetermined voltage to thereby detect the rotation and non-rotation states of the rotor.

Electronic timepiece

In an analog electronic watch having a calendar display the power required during change of the calendar display, about 6 hours out of 24, is greater than at other times. In order to effect economy in power consumption, the pulse for driving the watch motor during the time other than the period in which the calendar display is being changed is only sufficient to drive the time indicating means. In case the motor fails to step when such pulse is applied, this is detected by a detecting circuit and a corrective drive pulse is applied to the motor so as to drive it.

Electronic watch

An analog electronic timepiece has a stepping motor for rotationally driving the timepiece hands. The motor is driven by normal driving pulses during normal load conditions and in the event the normal driving pulses are unable to effect rotation of the motor, correction driving pulses of longer pulse width than the normal driving pulses are used. A detection circuit detects whether or not the motor has rotated by switching a resistance element in series with the motor drive coil after the application of each normal driving pulse. Rotation and non-rotation of the motor is determined by measuring the voltage across the resistance element and comparing the measured voltage with a reference voltage.

An electronic timepiece has a stepping motor comprised of a stator, rotor and coil, and circuitry for producing and applying driving pulses to the coil to effect stepwise rotation of the rotor. The presence of an external alternating magnetic field is detected by switching the coil from an open-circuit condition to a low impedance loop comprised of the coil and a low impedance element. The rotation of the rotor is detected by alternately switching the coil between the low impedance loop and a high impedance loop comprised of the coil and a high impedance element. Control circuitry controls the switching operations to ensure that the magnetic field detection and the rotor rotation detection are carried out at different times.

Detection device of electronic timepiece

An electronic timepiece having a stepping motor including a stator, rotor and coil, a driving circuit for applying driving pulses to the coil, an oscillating circuit for generating a time standard signal and a dividing circuit for dividing the time standard signal, is provided with a pulse combining circuit receptive of the output of the dividing circuit for producing a correction driving pulse having sufficient effective power to drive the motor under worst case conditions, a detector for detecting the rotation or non-rotation condition of the rotor after the application to the coil by the driving circuit of a normal driving pulse having less effective power than the correction driving pulse, and a controller for the driving circuit to apply normal driving pulses to the coil and responsive to the output of the detector to apply a correction driving pulse when a non-rotation condition is detected. The power consumption due to the pulse driving of the motor is minimized by incrementally decreasing the effective power of successive normal driving pulses and by incrementally increasing the effective power of successive normal driving pulses in response to the detection of a non-rotation condition by the detector.

An electronic timepiece has a stepping motor comprised of a stator, rotor and driving coil. A wave shaping circuit produces normal driving pulses and correction driving pulses having a longer pulse width than the normal driving pulses. A rotor rotation detection device detects rotation and non-rotation of the rotor after normal driving pulses are applied to the driving coil and in response to detection of a non-rotation condition, a correction driving pulse is applied to the driving coil. A magnetic field detection device detects the presence and absence of an external alternating magnetic field and in response to detection of a magnetic field, a driving pulse of longer pulse width than the correction driving pulses is applied to the driving coil to effect rotor rotation. The magnetic field detection device operates before the normal driving pulses are applied to the driving coil so that in the event of detection of a magnetic field, a driving pulse of sufficiently long pulse width will be applied to the driving coil to effect rotor rotation. In response to detection of an external alternating magnetic field by the magnetic field detection device, operation of the rotor rotation detection device is inhibited thereby conserving power and preventing mis-operation of the stepping motor.

An electronic timepiece includes a stepping motor having a stator, a drive coil and a rotor which is driven in one of at least two different states. The state of the driving motor is changed in response to a change in the load of the motor or in response to the locating of the motor in an external magnetic field.

An electronic timepiece of the type having a frequency dividing circuit, and a drive circuit for driving a motor having a rotor, a stator and a driving coil, is provided with a magnetic field detection device comprised of a low impedance closed loop including a low resistance element and the driving coil and a high impedance closed loop including a high resistance element and the driving coil. The driving coil develops an induced voltage when placed in an external alternating magnetic field and also functions to drive the rotor. The strength of the alternating magnetic field is measured by the voltage level developed across the high resistance element and the measuring sensitivity is improved by alternately switching between the low impedance closed loop and the high impedance closed loop. In response to the detection output of the magnetic field detection device, the effective power applied to the driving coil is increased so that the motor performance is not adversely affected by the external alternating magnetic field.

Magnetic field detection device for electronic timepiece

A load measuring device for a stepping motor of an analogue electronic timepiece having a stator, a rotor and a coil includes a pulse generator for producing a range of different pulse width normal driving pulses and a driving circuit for successively applying the driving pulses to the motor. A detector detects the rotation and non-rotation state of the rotor in response to the application of each driving pulse and a control circuit is responsive to the detection by the detector for controlling the application by the driving circuit of the minimum pulse width normal driving pulse capable of driving the motor. Each minimum pulse width driving pulse corresponds to the load on the motor at that time and an analyzer analyzes the pulse width of the driving pulses to thereby indicate the load on the motor.

Load measuring device for the gear train of a timepiece

In an electronic timepiece, a motor is driven by a pulse having a shorter pulse width than the conventional driving pulse and afterwards, a detection pulse is applied to the motor coil so as to determine rotation of the rotor. If the rotor fails to rotate a correction is effected by driving the motor by a pulse having a pulse width greater than the normal driving pulse.

In an electronic watch having a stepping motor, a battery voltage detecting circuit, a rotation detecting circuit for indicating rotation or non-rotation of the stepping motor and a motor driving power control circuit for applying a higher power drive pulse to the motor than a normal drive pulse upon detection of non-rotation, the operation of the rotation detecting circuit is inhibited upon indication of a low battery voltage condition and the motor is driven continuously with the higher power drive pulses for the extent of the battery low voltage condition. In this way, the electronic watch can be operated stably when the battery is at the end of its life and operated with lower power consumption during the time when the battery is operated at full voltage.

In an electronic watch having an oscillator for producing a time base signal and stepping motor, drive pulses are produced for normally driving the motor under normal load conditions. The rotation and non-rotation of the motor in response to the last drive pulse is detected in response to a detecting pulse, and if non-rotation has been detected, a predetermined plurality of correction pulses are applied to the motor for driving same, the correction pulses being sufficient to drive the motor under a high torque loading. In this way, power consumption is decreased since a high power driving is saved only for high torque loading conditions.

An electronic timepiece including a dividing circuit for developing different output pulse signals having different respective pulse repetition rates, a stepping motor and a drive circuit responsive to control signals for driving the stepping motor at a normal rate and for applying a correction pulse to the stepping motor according to the control signals. A pulse combining circuit combines the different output pulse signals from the dividing circuit for generating control signals and for applying the control signals to the drive circuit. The pulse combining circuit normally generates a control signal effective to drive the stepping motor at a normal rate, and the pulse combining circuit is responsive to a correction signal to control the drive circuit to apply a corrective pulse to the stepping motor. A detection circuit detects rotation and non-rotation of the stepping motor rotor and generates a detection voltage signal indicative of the state of rotation of the rotor. A voltage comparing circuit compares the detection voltage signal with a standard voltage value and applies a correction signal to the pulse combining circuit when non-rotation of the stepping rotor is detected after a drive pulse is applied to the stepping motor.

Electronic timepiece with rotation detector

An electronic timepiece including a stepping motor and a time-indicating hand moved in a stepwise manner by the stepping motor for indicating time. During normal operation the time-indicating hand moves at a normal periodic rate. When operating conditions such as a low battery cause the stepping motor to not rotate, correcting pulses are applied to the stepping motor to supply additional energy to it to cause it to rotate. Additionally, the correcting pulses cause the rotor, and the time-indicating hand to rotate at a rate different from the normal periodic rate to alert the timepiece user that some condition exists tending to cause non-rotation of the stepping motor.

An electronic timepiece includes a stepping motor having a coil and a rotor. Circuitry is provided for generating and applying alternating pulses to the motor coil to effect forward stepwise rotation of the motor rotor in a forward direction and for generating and applying alternating pulses to the motor coil to effect reverse stepwise rotation of the motor rotor in a reverse direction. The reverse rotation is achieved by sets of three alternating pulses with the first pulse of each set effecting incremental angular movement of the motor rotor in the forward direction followed by the second and third pulses which effect greater icremental angular movement of the motor rotor in the reverse direction to thereby obtain for each pulse set a net angular movement of the motor rotor in the reverse direction.

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Tokyo, Japan

Akira Torisawa