07323944 is referenced by 22 patents and cites 4 patents.

A PLL includes a charge pump, a loop filter, a VCO, and a calibration unit. The calibration unit performs coarse tuning to select one or multiple frequency ranges, performs fine tuning to determine an initial control voltage that puts the VCO near a desired operating frequency, measures the VCO gain at different control voltages, and derives VCO gain compensation values for the different control voltages. The calibration unit also pre-charges the loop filter to the initial control voltage to shorten acquisition time, enables the loop filter to drive the VCO to lock to the desired operating frequency, and performs VCO gain compensation during normal operation. For VCO gain compensation, the calibration unit measures the control voltage, obtains the VCO gain compensation value for the measured control voltage, and adjusts the gain of at least one circuit block (e.g., the charge pump) to account for variation in the VCO gain.

Title
PLL lock management system
Application Number
11/103743
Publication Number
7323944 (B2)
Application Date
April 11, 2005
Publication Date
January 29, 2008
Inventor
Chiewcharn Narathong
Laguna Niguel
CA, US
Amr M Fahim
Newport Beach
CA, US
Octavian Florescu
Berkeley
CA, US
Agent
Thomas Rouse
Larry J Moskowitz
Kenyon Jenckes
Assignee
Qualcomm Incorporated
CA, US
IPC
H03L 7/10
H03L 7/06
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