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US 5,001,685 AGranted
Electronic wristwatch with generator
AssigneeSeiko Epson Corporation
InventorMotomu Hayakawa
Life of this patent
Estimating the term…
Abstract
An electronic wristwatch including an a.c. generator having an output which is rectified using a half-wave rectifier. The half-wave rectified output of the generator is stored in a capacitor serving as a secondary power supply. Booster circuitry is operable for increasing and decreasing the voltage of the secondary power supply which is then applied across an auxiliary capacitor used for powering the wristwatch. Additional circuitry provides a suitable voltage across the auxiliary capacitor for driving the watch when the voltage across the secondary power supply is at or below a predetermined level. A pair of detecting circuits detect the maximum and minimum permissible voltage levels of the secondary power supply and auxiliary capacitor.
Claims28
An electronic wristwatch comprising:
- generating means for generating an alternating current;
- rectifier means for rectifying the alternating current;
- rechargeable secondary power supply means for storing electric power rectified by said rectifier means;
- auxiliary capacitance means for storing electric power;
- boosting means for transferring the electric power from said secondary power supply means to said auxiliary capacitance means and for increasing and decreasing the voltage of said secondary power supply means which is applied to said auxiliary capacitance means;
- first detecting means for detecting when a maximum permissible voltage level and a minimum permissible voltage level are applied to said auxiliary capacitance means wherein said booster means is responsive to said first detecting means indicating the occurrence of said maximum permissible level and said minimum permissible level of voltage across said auxiliary capacitance means for decreasing and increasing the voltage applied by the boosting means to the auxiliary capacitance means, respectively;
- and
- clock circuitry means for maintaining time;
- said auxiliary capacitance means providing power to said clock circuitry means.
6 more elements
An electronic wristwatch comprising:
- generating means for generating an alternating current;
- half-wave rectifier means for rectifying the alternating current;
- rechargeable secondary power supply means for storing electric power rectified by said half-wave rectifier means;
- overcharge limiting means for limiting the voltage applied to said secondary power supply means by said generating means and including antibraking means for minimizing the electromagnetic braking affect on the generating means and first switching means for redirecting the flow of current produced by the generating means through the overcharge limiting means rather than through the secondary power supply means;
- auxiliary capacitance means for storing electric power;
- clock circuitry powered by the voltage across the auxiliary capacitance means;
- immediate start means coupled to the auxiliary capacitance means for increasing the voltage applied to the auxiliary capacitance means when the voltage of the secondary power supply means is at or below a minimum permissible level and including at least one resistor and second switching means electrically connected in parallel;
- first detecting means for detecting and indicating when a maximum permissible voltage level and said minimum permissible voltage level of said secondary power supply means occur, said first switching means of said overcharged limiting means responsive to indication by said first detecting means that said maximum permissible voltage level of said secondary power supply means is present to switch to an electrically conductive state and said second switching means of said immediate start means responsive to indication by said first detecting means that the voltage level of the secondary power supply means is at or below its minimum permissible level to switch to an electrically open state;
- boosting means operable for increasing and decreasing the voltage applied to the auxiliary capacitance means wherein the boosting means includes at least one booster capacitor, booster switching means and booster control means;
- said booster switching means responsive to said booster control means for rearranging the connections between the at least one booster capacitor, auxiliary capacitance means and secondary power supply means;
- and
- second detecting means for detecting and indicating when a maximum permissible voltage level and a minimum permissible voltage level are applied to said auxiliary capacitance means wherein said booster control means is responsive to indication by said second detecting means that said maximum permissible level and said minimum permissible level of voltage across the auxiliary capacitance means are present for controlling the decrease and increase of voltage applied by the boosting means to the auxiliary capacitance means, respectively.
9 more elements
An electronic wristwatch comprising:
- a generator having at least a rotor, a stator, a coil and a mechanism for rotating said rotor to convert mechanical energy to electrical energy which includes an alternating voltage across the coil;
- a rectifier circuit for rectifying the alternating voltage;
- a rechargeable secondary power supply for storing the electric power rectified by said rectifier circuit;
- and
- an overcharge preventing circuit for preventing overcharge of said secondary power supply, wherein said overcharge preventing circuit includes switching means and rectifier means connected electrically in series and which together are connected electrically in parallel to said coil;
- auxiliary capacitor means having a storage capacity less than said secondary power supply and for storing electric power;
- and
- clock circuitry means for maintaining time;
- said auxiliary capacitance means providing power to said clock circuitry means;
- wherein said switching means are operable for switching between ON and OFF states, said switching means switching to the ON state when the voltage across the rechargeable secondary power supply reaches a predetermined maximum value and wherein said rectifier means is operable for controlling the direction of current flow through said switching means to prevent current flow through said switching means when said switching means is in the OFF state.
7 more elements
Dependencies are inferred from the claim text.