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:
Mar. 10, 1998
Filed:
Jul. 03, 1996
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
An SRAM according to the present invention includes a voltage-down circuit and an internal circuit. The voltage-down circuit includes three resistors, two PMOS transistors and an NMOS transistor. One PMOS transistor directly applies an external power supply voltage to the internal circuit. The NMOS transistor applies a voltage obtained by reducing the external power supply voltage by a threshold voltage thereof to the internal circuit. The value of a predetermined voltage as a condition for switching such application of the voltage by the PMOS transistor and application of the voltage by the NMOS transistor is determined by the resistance ratio of the two resistors. Each of the three resistors is formed by a plurality of resistance elements of one kind. Thus, even if the process parameter varies, the ratio of the resistance values of the two resistors which determines the switching point can be kept constant, thereby preventing variation in switching point.