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. 01, 2013
Filed:
Feb. 12, 2011
Akira Matsumoto, Hino, JP;
Tatsunori Usugi, Hamura, JP;
Akira Matsumoto, Hino, JP;
Tatsunori Usugi, Hamura, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A digital compensation phase locked loop circuit of a semiconductor device includes a phase locked loop circuit including a voltage controlled oscillator having capacitors at oscillation nodes and consecutively controlled by an applied voltage, and a digital compensation circuit which variably controls the capacitors at the oscillation nodes of the voltage controlled oscillator in accordance with an input phase difference. A gain of the conventional voltage controlled oscillator whose gain is determined by an applied voltage is discretely changed by a control signal of the digital compensation circuit. The digital compensation circuit dynamically controls the gain so as to secure the optimum phase margin by applying a load (capacitor) to the oscillation node of the voltage controlled oscillator with respect to a phase lead and decreasing the load (capacitor) with respect to a phase delay.