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:
May. 16, 2000
Filed:
Mar. 06, 1998
Yoshihiro Sanada, Tokyo, JP;
Hiroshi Eto, Tokyo, JP;
Oki Electric Industry Co., Ltd., Tokyo, JP;
Abstract
The difference voltage between the terminal voltage VB of a rechargeable battery BAT and a reference voltage Vz1 is amplified at an initial gain, thereby reducing an amplified voltage value S12. This amplified voltage value S12 is A/D converted into digital value S13. Further, an electrical signal S18 is detected corresponding to the ambient temperature around the battery and is then A/D converted into a digital value S19. Digital values S13 and S19 charge with the progress of charging of the rechargeable battery. The change in these digital values is read by CPU 14 one after another, and the gain used in amplification of the difference voltage is renewed by the gains corresponding to digital values S13 and S19, which are stored in advance in a ROM 20. In the same manner, the reference voltage used in amplification of the difference voltage is renewed by reference voltages Vz2, Vz3, and Vz4 one by one with the progress of charging of the rechargeable battery. When the digital value S13 is decreased, CPU 14 judges that charging of the rechargeable battery is completed, thus a voltage drop -.DELTA.V being caused in the terminal voltage VB, and controls a constant current circuit portion 17 to terminate the supply of the charging current S17.