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:
Oct. 09, 1990
Filed:
Feb. 14, 1989
Yoshiaki Kato, Tanashi, JP;
Harumi Yuyama, Yamanahi, JP;
Tutomu Ojima, Mizusawa, JP;
Hiromi Ishikawa, Morioka, JP;
Citizen Watch Co., Ltd., Tokyo, JP;
Abstract
An IC card such as cash card is disclosed. The IC card has a RAM, a control circuit for controlling access to the RAM, and a power supply circuit receiving outside energy and supplying power to the RAM and the control circuit. A first voltage detector produces a starting output when supply voltage of the power exceeds a predetermined first reference voltage. A second voltage detector produces a control signal when the supply voltage exceeds a predetermined second reference voltage, which is higher than the first reference voltage. An AND gate is provided to produce a RAM control signal for operating the RAM when the starting signal and the control signal are applied thereto.