Kabushiki Kaisha Suwa Seikosha

Shimauchi Seiki Kabushiki Kaisha

Shamauchi Kieki Kabushiki Kaisha

Masuo Kitano

Kenji Sakamoto

Hiroyuki Chihara

Masahito Yoshino

Jiro Ito

Circuits are provided for avoiding misdetection of a non-rotated condition after driving the timepiece stepping motor. Voltages induced in the rotor coil by external high frequency magnetic fields, and current produced in the coil by lower frequency AC magnetic fields are detected. When a high frequency or AC magnetic field of sufficient intensity to cause a false indication of motor rotation is detected, the motor is next driven with a pulse having greater width than the normal driving pulse so as to assure operation of the motor. A period is provided, before the normal driving pulse would be applied, to detect AC magnetic fields and a period preceding the period for detection of AC magnetic fields is provided for detection of high frequency magnetic fields. A comparator or inverter is used to determine whether the levels of external magnetic fields are sufficient to cause misdetection of rotor position.

Analog electric timepiece

In an electronic analog timepiece an automatic sequence of events determines the proper magnitude of a detection resistor which is used in series with the motor coil so as to determine whether in normal operation the rotor is rotated or not when driven. A detection resistor is used in series with motor coil but only after a fixed time has passed from initiation of detection current flow. The detection resistor is logically variable and selected automatically in accordance with the motor's mechanical load at the time of switching on the power source or releasing the analog timepiece from a resetting operation. The resistance is formed part of the integrated circuit.

Electronic analog timepiece with rotation detection circuit

A detection circuit for an electronic timepiece for ascertaining whether the power supply has been properly applied. A first switching element is in parallel with a capacitor and a second switching element is in series. A booster circuit raises the battery voltage to serve as a power source, which is applied to the series-connected capacitor and second switching element. When boosted voltage becomes higher than battery voltage, indicating that the power supply is properly applied, the first switching element is turned OFF and the second switching element is turned ON. If the battery is not properly applied, the first switching element is ON and the second switching element is OFF. The circuit is also suited to a timepiece with a voltage reduction circuit.

Detection circuit for an electronic timepiece

A timepiece includes in addition to the conventional timekeeping circuits, high load, that is, high current circuits such as an alarm driving circuit and a lamp driving circuit. Low load, small current systems such as the oscillator, divider, display drivers and display for timekeeping are operated directly from the battery voltage source when the high load circuits are off. When the high load circuits are on, the low load circuits are disconnected from the battery and operate from an electric charge stored in a capacitor connected in parallel with the low load circuits. The high load circuits are driven intermittently at a high frequency to reduce power consumption and to permit recharging of the storage capacitor during off-periods. The drive frequency is sufficiently high such that an illumination lamp shows no flicker and brightness is controlled by duty cycle.

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Matsumoto, Japan

Masuo Kitano