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. 20, 1998
Filed:
Oct. 28, 1996
Applicant:
Inventor:
Sung-Hun Oh, Phoenix, AZ (US);
Assignee:
VLSI Technology, San Jose, CA (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H03D / ;
U.S. Cl.
CPC ...
327 12 ;
Abstract
A phase-frequency detector for a phase-locked loop (PLL) circuit has symmetrical phase detection characteristics and produces symmetrical activation times on the 'up' and 'down' outputs for connection to a PLL charge pump circuit. The symmetrical characteristics are accomplished by using RS latch circuits at the outputs of the phase-frequency detector to provide the same loads and the same propagation delay for both the 'up' and the 'down' outputs. In addition, cross-wired sequential gates are used for at least some of the gates in the logic gate array of the detector to produce the same propagation delays in the gates.