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US 4,397,563 AGranted
Power circuit for electronic wristwatch
AssigneeKabushiki Kaisha Suwa Seikosha
InventorMatsuo Ichinose
Life of this patent
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Abstract
A power circuit for an electronic wristwatch is provided wherein voltage reduction circuit means is positioned intermediate a battery source and at least a portion of the circuitry of the timepiece to be driven by the battery source. The battery source is preferably a lithium battery. The voltage reduction circuit means include a capacitor and other circuit components formed on an integrated circuit substrate.
Claims14
A power circuit for an electronic wristwatch having a voltage source;
- circuit means having a plurality of circuit elements, said circuit means operating from said voltage source, a portion of said circuit elements operating with an input voltage lower than the voltage of said voltage source,
- voltage reducing means connected intermediate said voltage source and said portion of said circuit elements operating at said reduced voltage, said voltage reducing means including:
- a current source for storing and delivering power at reduced voltage to said portion of circuit elements,
- reference voltage circuit means having a reference voltage output level, and including a differential amplifier for controlling the voltage level by sensing said reference voltage and limiting the voltage of said current source in proportion to said reference voltage, one input to said differential amplifier being connected to one end of said portion of circuit elements.
1 more element
Dependencies are inferred from the claim text.