Invention Grant
- Patent Title: Charge pump current compensation for phase-locked loop frequency synthesizer systems
- Patent Title (中): 锁相环频率合成器系统的电荷泵电流补偿
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Application No.: US12141499Application Date: 2008-06-18
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Publication No.: US08010072B1Publication Date: 2011-08-30
- Inventor: Lalitkumar Nathawad
- Applicant: Lalitkumar Nathawad
- Applicant Address: US CA San Jose
- Assignee: Atheros Communications, Inc.
- Current Assignee: Atheros Communications, Inc.
- Current Assignee Address: US CA San Jose
- Agency: Bever, Hoffman & Harms, LLP
- Agent Jeanette S. Harms
- Main IPC: H04B1/06
- IPC: H04B1/06 ; H04B7/00

Abstract:
A technique for improving frequency synthesizer performance by frequency-compensating charge pump current in order to maintain a consistent loop bandwidth over a wide operating frequency range is described. A relationship between the capacitance value associated with a voltage controlled oscillator resonant tank and the magnitude of current pulses in a related charge pump is exploited to bound the loop bandwidth of the frequency synthesizer over both operating frequency and process variation. A control state machine generates digital coarse tune values that dynamically select a capacitance for the resonant tank, such that the voltage controlled oscillator operates within an optimal control voltage range. Each dynamically selected capacitance value is then used to determine the magnitude of current pulses in the charge pump.
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