Electronic timepiece
First Claim
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1. An electronic timepiece comprising:
- a stepping motor having a coil and a rotor;
means for generating a normal drive pulse sufficient to drive the motor under normal loading but insufficient to drive the same under worst case loading, a drive correction pulse sufficient to drive the motor under worst case loading and two out-of-phase detection pulses;
a drive circuit receptive of the normal drive pulse and the drive correction pulse for driving the stepping motor; and
a detection circuit for detecting the rotary position of the motor rotor comprising a detection element, and a voltage comparison circuit for comparing the voltage drop across said detection element during the first detection pulse when current flows in one direction of the motor coil with the voltage drop across said detection element during the second detection pulse when current flows in the opposite direction of the motor coil whereby if the rotor is rotating, the current will flow in the opposite direction in the coil and the voltage drop is lower than that during the first detection pulse and if the rotor is not rotating, the voltage drop is greater.
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Abstract
An electronic timepiece reduces power consumption by normally driving the stepping motor with a short pulse and driving the motor with a wide pulse under heavy load conditions by sensing the rotor position. A detection circuit senses the voltage drop across a detection element in series with the motor coil for driving a first detection pulse and senses again for driving a second detection pulse. If the second voltage drop is larger, then the rotor is not rotating whereupon the wide pulse is used to drive the motor.
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Citations
4 Claims
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1. An electronic timepiece comprising:
- a stepping motor having a coil and a rotor;
means for generating a normal drive pulse sufficient to drive the motor under normal loading but insufficient to drive the same under worst case loading, a drive correction pulse sufficient to drive the motor under worst case loading and two out-of-phase detection pulses;
a drive circuit receptive of the normal drive pulse and the drive correction pulse for driving the stepping motor; and
a detection circuit for detecting the rotary position of the motor rotor comprising a detection element, and a voltage comparison circuit for comparing the voltage drop across said detection element during the first detection pulse when current flows in one direction of the motor coil with the voltage drop across said detection element during the second detection pulse when current flows in the opposite direction of the motor coil whereby if the rotor is rotating, the current will flow in the opposite direction in the coil and the voltage drop is lower than that during the first detection pulse and if the rotor is not rotating, the voltage drop is greater. - View Dependent Claims (2, 3, 4)
- a stepping motor having a coil and a rotor;
Specification