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. 22, 2000
Filed:
Apr. 28, 1998
Carl M Stanchak, Colorado Springs, CO (US);
Michael J Seymour, Colorado Springs, CO (US);
Atmel Corporation, San Jose, CA (US);
Abstract
An oscillator circuit having a first node oscillating with a first indeterminate duty cycle and having a second node oscillating with a predetermined second duty cycle. Both nodes oscillate at similar frequencies. A variable current source and a switch are coupled in series between Vcc and ground with the output of the variable current source being the second node. The first node controls the switch, which is closed when the first node is at a first logic state and is opened when it is at a second logic state. During each cycle, a monitoring circuit measures the time span that the first node is at the first logic state and adjusts the magnitude of the variable current source to make it directly proportional to the measured time span. By adjusting the variable current source, the second node can be made to reach a desired voltage level in a desired amount of time during each cycle. In a second embodiment, a current limiting transistor is inserted between the second node and the switch. The current limiting transistor is controlled by the monitoring circuit and is made to reduce the influence of the switch on the second node as the duty cycle of the first node approaches the predetermined second duty cycle.