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:
Dec. 20, 1994
Filed:
Aug. 26, 1991
Kazumasa Kimura, Yamato-Koriyama, JP;
Masato Hiramoto, Soraku, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
A stored data protection apparatus for an electronic device has a CPU (20) and a volatile memory (21) controlled by the CPU for storing data therein. Both of the CPU and the volatile memory ace supplied power voltage from a main battery (22) in normal operation of the device. The volatile memory as supplied power voltage from a back-up battery (23) when the main battery is removed from the device. The apparatus has a switch (29) operable in first and second positions, taking the first position in the normal operation of the device, and being switched from the first position to the second position when the main battery is removed from the device, a circuit (44, 48) for inhibiting the CPU to access the volatile memory when the switch is in the second position, and a circuit (38, 34, 42, 43) for releasing the inhibition of the CPU by the inhibiting circuit when the switch is switched from the second position to the first position.