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:
May. 05, 1992
Filed:
Sep. 13, 1990
Takaaki Suzuki, Kawasaki, JP;
Takeo Tatematsu, Sagamihara, JP;
Fujitsu Limited, , JP;
Abstract
A wafer-scale semiconductor memory device includes a wafer, and a plurality of memory chips formed on the wafer. The memory chips contain a memory chip which includes a storage circuit, and a switching transistor which selectively connects the storage circuit to a power supply line in response to a control signal. The memory chip also includes a control logic circuit which writes data into the storage circuit and reads out data from the storage circuit and which generates a logic signal used for controlling the transistor. Further, the memory chip includes a fail-safe circuit having a circuit element having a status showing whether or not the control logic circuit is malfunctioning. The fail-safe circuit generates the control signal from the logic signal and the status of the circuit element so that when the circuit element has the status showing that the control logic circuit is malfunctioning, the fail-safe circuit outputs the control signal which instructs the switching element to disconnect the storage circuit from the power supply line irrespective of the logic signal.