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:
Jul. 15, 2003
Filed:
Feb. 02, 2001
Kouzou Ichimaru, Kunisaki-machi, JP;
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
Frequency synthesizer ( ) has compensation circuit ( ) and correction circuit ( ). Compensation circuit ( ) has compensation capacitor ( ), while correction circuit ( ) has detection capacitor ( ). Correction circuit ( ) charges/discharges detection capacitor ( ) corresponding to the control signal of the PLL loop to generate a reference voltage. Compensation circuit ( ) applies a voltage to compensation capacitor ( ) on the basis of the reference voltage to cancel the ripple current included in the control signal. By making the time for charging/discharging detection capacitor ( ) equal to one period of a comparison signal obtained by dividing the frequency of the external output signal of the PLL loop, it is possible to generate a reference voltage which can follow changes in the external output signal. Consequently, the ripple current can be correctly cancelled out by following the changes in the external output signal.