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. 25, 2001
Filed:
Feb. 15, 2001
Katsuyoshi Mitsui, Hyogo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A semiconductor memory device includes a voltage detection circuit. The voltage detection circuit uses a voltage division circuit to derive from a test command voltage forming a test command signal EXTSH a voltage fraction which is one-third of the original voltage and uses another voltage division circuit to derive from an external supply voltage a voltage fraction which is a half of the original voltage. The two voltage fractions are compared by a comparison circuit of differential amplification type to detect the test command voltage and cause transition of a test target circuit of the semiconductor memory device to a test mode. P channel MOS transistors constituting the voltage division circuits all operate in resistance mode. The test command signal of high-voltage can thus be detected.