The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 08, 2005
Filed:
Dec. 10, 2002
Katsuyoshi Aihara, Kawagoe, JP;
Takaaki Nozaki, Iruma, JP;
Ryoji Iwakura, Sayama, JP;
Citizen Watch Co., Ltd., Tokyo, JP;
Abstract
Charging a storage cell requires the electromotive force exerted at a photogenerating cell in addition to the voltage equal to or higher than the forward on voltage developed at an backflow preventing diode. Therefore, the charging is inefficient. Moreover, the area of the backflow preventing diode must be large in consideration for a current supply from the photogenerating cell at a high intensity of illumination. A charging circuit, constructed using a differential amplifier, which has a power supply therefor separated from another power supply, is used as a direction-of-current detecting circuit that detects the direction of current from a voltage difference between two different power supplies. Consequently, a switch is logically turned on or off depending on whether charging or non-charging is under way. Thus, on voltage to be developed during charging is lowered. Moreover, the size or area of a transistor that acts as a logical circuit is made smaller than that of the backflow preventing diode. Furthermore, the energy of a storage cell included in the charging circuit is hardly consumed in any states.