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:
Apr. 29, 2014
Filed:
Jun. 01, 2010
Go Utamaru, Ibaraki, JP;
Go Utamaru, Ibaraki, JP;
Advantest Corporation, Tokyo, JP;
Abstract
A PLL circuit according to the present invention includes a VCO that outputs an VCO signal having a frequency according to an input voltage, a loop filter that feeds a voltage according to an input current to the VCO, a phase comparator that outputs a phase difference pulse having a width according to a phase difference between a first input signal and a second input signal, a charge pump circuit that receives the phase difference pulse, and inputs the current to the loop filter, and a phase-difference-pulse stop unit that stops the input of the phase difference pulse to the charge pump circuit in a non-input state in which an REF signal (reference frequency signal) is not input. The first input signal is the REF signal itself or a signal obtained by dividing the frequency of the REF signal, and the second input signal is the VCO signal itself or a signal obtained by dividing the frequency of the VCO signal.