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:
Dec. 04, 2001
Filed:
Nov. 06, 1998
Alexander W. Hietala, Phoenix, AZ (US);
David M. Gonzalez, Elgin, IL (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A PLL (,) includes a phase detector (,) and a charge pump (,or,). The phase detector (,) includes a first D-type flip flop (,), a second D-type flip flop (,) and an AND gate forming a reset circuit (,). The charge pump (,or,) includes an up current source (,) and a down current source (,). The up current source (,) provides a constant current. The down current source (,) varies responsive to an output signal (,) generated by the second D-type flip flop (,). The constant current provided by the up current source (,) is made to be less than one half the current provided by the down current source (,) to bias the charge pump (,or,) in a negative direction to minimize false locks between the phase of a divided reference frequency signal (,) and the phase of a divided voltage controlled oscillator frequency signal (,). Alternatively, the up current source (,) may be controlled in an analogous manner with the down current source (,) being held constant to achieve a similar effect and advantage.