Invention Grant
- Patent Title: Phase locked loop with adaptive biasing
- Patent Title (中): 具有自适应偏置的锁相环
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Application No.: US13434946Application Date: 2012-03-30
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Publication No.: US08487677B1Publication Date: 2013-07-16
- Inventor: Dashun Xue
- Applicant: Dashun Xue
- Applicant Address: US TX Austin
- Assignee: Freescale Semiconductor, Inc.
- Current Assignee: Freescale Semiconductor, Inc.
- Current Assignee Address: US TX Austin
- Agent Gary Stanford
- Main IPC: H03L7/06
- IPC: H03L7/06

Abstract:
A phase locked loop including first and second charge pumps, a voltage buffer and a bias generator for adaptive biasing for improved performance. A voltage controlled oscillator, feedback circuit and phase detector portions may be provided to operate similar to conventional configurations. The first charge pump receives an adjust signal, such as from the phase detector, and selectively charges an intermediate node. The second charge pump receives the adjust signal and selectively charges a control node developing the control voltage for the VCO. A loop filter capacitor is referenced to the intermediate node. The voltage buffer, replacing the loop filter resistor, buffers the intermediate node and drives the control node. The bias generator converts the control voltage to a converter bias current based on the control voltage and adjusts the charge pump currents and a bias current of the voltage buffer.
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