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:
Apr. 20, 2004
Filed:
Oct. 28, 2002
Yoshimasa Yoshimura, Tokyo, JP;
Renesas Technology Corp., Tokyo, JP;
Abstract
A nonvolatile semiconductor memory unit which is provided with a nonvolatile semiconductor memory and a controller for performing a read operation, a write operation and an erase operation on the nonvolatile semiconductor memory unit, including an external power source which derives its supply of electric power from outside, an internal power source which derives its supply of electric power from a secondary battery and is connected to the nonvolatile semiconductor memory and the controller, a voltage detecting circuit for detecting a voltage of the external power source and a switching circuit which is provided between the external power source and the internal power source and is subjected to on-off control by an output of the voltage detecting circuit so as to enable and disable the external power source, respectively.