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:
Feb. 05, 2008
Filed:
May. 12, 2005
Akihiro Sawada, Osaka, JP;
Akihiro Sawada, Osaka, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A PLL frequency synthesizer is provided with a linearization circuitwhich receives an oscillation frequency control signal Vfrom a loop filter LF. The linearization circuitoutputs a charge pump current control signal CP, depending on a potential level of the oscillation frequency control signal V. The larger the value of the charge pump current control signal CP, the higher the potential level. A charge pump CP receives the charge pump current control signal CP, and causes a current corresponding to the value to flow in or out. Therefore, with a simple circuit structure, loop gain characteristics of the PLL frequency synthesizer can be regulated to be constant. Therefore, even when a variable capacitance element incorporated in a voltage control oscillator has nonlinear characteristics with respect to the potential of the input oscillation frequency control signal, the loop gain characteristics of the PLL frequency synthesizer having the voltage control oscillator can be regulated to be constant.