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:
Jun. 15, 1999
Filed:
Feb. 27, 1997
Yutaka Takikawa, Hyogo, JP;
Mitsubishi Electric Semiconductor Software Co., Ltd., Hyogo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A phase-locked loop (PLL) circuit includes a low-pass filter, a voltage controlled oscillator that produces a PLL signal having a frequency that differs according to a control voltage supplied by the low-pass filter, a phase detector which receives the PLL signal and a reference signal and detects a phase difference between them to produce an error signal, and a charge pump that, in response to the error signal, supplies a charge to the low-pass filter or extracts a charge from the low-pass filter. The charge pump includes a variable resistance element the resistance of which varies when the error signal is applied, thereby nonlinearly adjusting the charge supplied to or extracted from the low-pass filter with respect to the duration of the error signal from the phase detector.