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. 29, 2000
Filed:
Jul. 07, 1994
Michael V Cordoba, Colorado Springs, CO (US);
Kim C Hardee, Colorado Springs, CO (US);
United Memories, Inc., Colorado Springs, CO (US);
Abstract
A constant current source is used to provide a constant current to set a delay which defines the period of the output of the oscillator. The delay is preferably set by charging a capacitor with the constant current. Because the current is independent of variations in V.sub.CC and temperature, the capacitor will charge for a given period. Therefore, the frequency or period of oscillation will also be fixed and independent of variation in V.sub.CC or temperature. A current limiting circuit and latch are provided to generate an output which will be transmitted through one or a series of inverters. In an alternate embodiment, a differential amplifier is provided between the delay circuit and the current limiting circuit. This differential amplifier is typically needed in a case where VCC is not well-controlled to provide an output signal which has an appropriate voltage. A method of generating an oscillating output for refreshing a DRAM and a method for refreshing a DRAM are also disclosed.