Method of reducing the power consumption of the stepping motor of an electronic timepiece and an electronic timepiece employing the method
First Claim
1. A method for reducing the power consumption of the stepping motor of an electronic timepiece, by automatically establishing the width of voltage drive pulses supplied to the motor, in accordance with its load and its supply voltage, the motor comprising at least one actuating coil, a stator and a rotor which rotates through a given angle when a voltage drive pulse is applied to said actuating coil, comprising the steps of measuring, during each voltage drive pulse, the variation in the magnetic induction flux in the stator, and interrupting the voltage drive pulse when this variation in flux reaches a predetermined value.
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Abstract
The present invention comprises measuring, upon application of a drive pulse to the actuating coil 5 of the stepping motor, the variation in the magnetic induction flux in the stator of the motor, and interrupting the drive pulse when the variation in flux reaches a predetermined value. Measurement of the variation in flux may be effected, for example, by detecting the current in the actuating coil and integrating the difference between the supply voltage of the actuating coil and the product of the current by the d.c. resistance of the coil, or by providing an auxiliary detection coil 71 and integrating the voltage induced therein in an integrator 73, 74. When the integrator outputs exceeds the magnitude of either a positive or negative reference voltage, a comparator circuit 78, 79, 81 provides the signal to a circuit 13 to terminate the drive pulse.
The foregoing abstract is not to be taken as limiting the invention described herein, and in order to understand the full nature and extent of the technical disclosure herein, reference should be made to the accompanying drawings and detailed description.
22 Citations
13 Claims
- 1. A method for reducing the power consumption of the stepping motor of an electronic timepiece, by automatically establishing the width of voltage drive pulses supplied to the motor, in accordance with its load and its supply voltage, the motor comprising at least one actuating coil, a stator and a rotor which rotates through a given angle when a voltage drive pulse is applied to said actuating coil, comprising the steps of measuring, during each voltage drive pulse, the variation in the magnetic induction flux in the stator, and interrupting the voltage drive pulse when this variation in flux reaches a predetermined value.
- 5. An electronic timepiece comprising an oscillator for producing a standard frequency signal, a frequency divider circuit which is connected to the oscillator to produce a low-frequency time signal, a stepping motor, comprising at least one actuating coil, a stator and a rotor, a supply circuit for periodically producing and supplying voltage drive pulses to the actuating coil in response to the time signal, and monitoring means for controlling the supply circuit for automatically establishing the width of the drive pulses in accordance with the value of the load and the supply voltage of the motor, the monitoring means comprising a measuring device for measuring, in respect of each voltage drive pulse, the variation in the magnetic induction flux in the stator and producing a measuring signal representing the value of the variation in flux, and means responsive to the measuring signal to apply to the supply circuit, a signal for interrupting the voltage drive pulse to establish its width when the variation in flux reaches a predetermined value.
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13. A method for reducing the power consumption of the stepping motor of an electronic timepiece to its load and to its supply voltage, the motor comprising at least one actuating coil, a stator and a rotor which rotates through a given angle when a voltage drive pulse is applied to said actuating coil, comprising the steps of:
applying a drive pulse to said actuating coil including the step of establishing the width of the drive pulse, said step of establishing including; i. applying voltage to said coil; ii. measuring the magnetic induction flux in the stator; iii. comparing the measured flux with a predetermined value; and iv. terminating application of voltage to said coil when the measured flux reaches a predetermined value, whereby the width of voltage drive pulses are automatically adapted to the motor'"'"'s load and supply voltage.
Specification