Quartz crystal timepiece
AssigneeKabushiki Kaisha Suwa Seikosha
InventorHiroyuki Chihara
Life of this patent
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Abstract
A battery-powered quartz crystal timepiece is provided with a battery voltage detecting circuit utilizing the threshold voltage of a field effect transistor as a battery failure indicator. The voltage level at which failure is indicated may be selectively controlled by adjusting a load resistance value of the field effect transistor or a voltage divider intermediate the transistor and battery. The battery voltage detecting circuit may operate intermittently, the sampled output of the detecting circuit being stored in a memory circuit.
Claims30
An electronic timepiece comprising driving circuit means for producing timekeeping signals;
- display means operatively coupled to said timekeeping circuit means for the visual display of time in response to said timekeeping signal;
- a battery power source operatively coupled to said driving circuit means for powering same;
- and battery failure detecting circuit means coupled to said battery for producing a signal representative of impending battery failure when the voltage of said battery falls below a predetermined level, said battery-voltage detecting circuit means including a field-effect transistor and means coupling said field-effect transistor to said battery whereby said predetermined voltage level is detected by the threshold voltage of said field-effect transistor.
An electronic timepiece comprising timekeeping circuit means for producing timekeeping signals representative of actual time;
- display means operatively coupled to said timekeeping means for the visual display of time in response to said timekeeping signals;
- a battery power source;
- battery failure detecting circuit means having an input and an output for producing a battery failure signal representative of impending failure of said battery when the voltage level applied to its input representative of the voltage of said battery reaches a predetermined level;
- means for periodically applying a signal representative of said battery voltage to said battery failure detection circuit means input;
- and memory means coupled to said battery failure detection circuit means output for storing the battery failure signal.
Dependencies are inferred from the claim text.