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:
Jan. 04, 2000
Filed:
Jul. 16, 1998
Jason Chen, San Jose, CA (US);
Ping Xu, Milpitas, CA (US);
Seiko Epson Corporation, Tokyo, JP;
Abstract
A CMOS voltage controlled oscillator (VCO) having an improved voltage-to-current converter and an active MOS load operating in the triode region to provide improved performance characteristics including a small differential logic swing and a high frequency output. The voltage-to-current converter of the CMOS VCO comprises a pair of MOS transistors, one of which has an aspect ratio (W.sub.P /L.sub.P) and the other of which has an aspect ratio (W.sub.P /L.sub.P)/n, wherein 1<n<4. This configuration causes a third MOS transistor in the voltage-to-current converter to operate exclusively in the triode region. The CMOS VCO also includes an ICO portion having a plurality of delay stages connected in a ring configuration. Each of the delay stages comprises a pair of input MOS transistors and a pair of load MOS transistors. In accordance with the invention, the voltage-to-current converter causes each of the load MOS transistors to operate in the triode region.