Invention Grant
- Patent Title: PLL circuit with VCO gain control
- Patent Title (中): 具有VCO增益控制的PLL电路
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Application No.: US12751395Application Date: 2010-03-31
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Publication No.: US08040191B2Publication Date: 2011-10-18
- Inventor: Yoshitaka Hirai
- Applicant: Yoshitaka Hirai
- Applicant Address: JP Kanagawa
- Assignee: Renesas Electronics Corporation
- Current Assignee: Renesas Electronics Corporation
- Current Assignee Address: JP Kanagawa
- Agency: Foley & Lardner LLP
- Priority: JP2009-104830 20090423; JP2010-010054 20100120
- Main IPC: H03L7/00
- IPC: H03L7/00

Abstract:
A PLL circuit includes first and second charge pump circuits controlling an output voltage according to an output signal of a phase comparator, a first filter filtering out predetermined frequency component included in a signal generated according to current output from the first charge pump circuit, and outputting the signal as a first voltage signal, a second filter inputting a current output from the second charge pump circuit and outputting a predetermined constant voltage as a second voltage signal, a voltage control unit outputting a third voltage signal according to a comparison result between the first voltage signal output from the first filter and a reference voltage signal, and a voltage controlled oscillator that has a first low gain property, a second low gain property, and a high gain property, and is controlled by the first to third voltage signals to generate an oscillating frequency.
Public/Granted literature
- US20100271141A1 PLL CIRCUIT Public/Granted day:2010-10-28
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