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. 12, 2008
Filed:
Dec. 01, 2005
Atsushi Obinata, Hachioji, JP;
Atsushi Obinata, Hachioji, JP;
Seiko Epson Corporation, , JP;
Abstract
A semiconductor device including: a DRAM which is a volatile memory; a PLL circuit which outputs an operation clock signal generated by multiplying an input clock signal; a circuit block which operates in synchronization with the operation clock signal; first and second refresh controllers for requesting a refresh operation of the DRAM; and a memory controller which arbitrates between an access request for the DRAM from the circuit block and a refresh request from the first refresh controller. In a first mode in which the PLL circuit operates, the first refresh controller issues the refresh request to the DRAM controller. In a second mode in which the operation of the PLL circuit stops, the second refresh controller issues the refresh request, the refresh request bypassing the DRAM controller.