Invention Grant
- Patent Title: Hybrid analog and digital control of oscillator frequency
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Application No.: US14554798Application Date: 2014-11-26
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Publication No.: US09705514B2Publication Date: 2017-07-11
- Inventor: Michael H. Perrott
- Applicant: Silicon Laboratories Inc.
- Applicant Address: US TX Austin
- Assignee: Silicon Laboratories Inc.
- Current Assignee: Silicon Laboratories Inc.
- Current Assignee Address: US TX Austin
- Agency: Zagorin Cave LLP
- Main IPC: H03L7/06
- IPC: H03L7/06 ; H03L7/099 ; H03L7/08 ; H03L7/093

Abstract:
A hybrid analog/digital control approach for a digitally controlled oscillator augments a digital control path with an analog control path that acts to center the digital control path control signal within its range. The digital control path controls a first group of varactors within an oscillator tank circuit using a digital filter and a delta sigma modulator, which generates a dithered control signal for at least one of the first group of varactors. The analog control path controls a second group of varactors in the tank circuit but actively tunes only one varactor at a time. The analog control path performs relatively low bandwidth centering of the digital control signal resulting in negligible impact on PLL bandwidth, stability, and noise performance. Instead, the digital control path dominates in setting the PLL dynamic and noise behavior, and has reduced range requirements due to the centering action.
Public/Granted literature
- US20150145566A1 HYBRID ANALOG AND DIGITAL CONTROL OF OSCILLATOR FREQUENCY Public/Granted day:2015-05-28
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