Invention Grant
- Patent Title: Apparatus and methods for digital fractional phase locked loop with a current mode low pass filter
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Application No.: US17101665Application Date: 2020-11-23
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Publication No.: US11218155B2Publication Date: 2022-01-04
- Inventor: Tingjun Wen , Sadok Aouini , Naim Ben-Hamida , Mahdi Parvizi , Matthew Mikkelsen
- Applicant: Ciena Corporation
- Applicant Address: US MD Hanover
- Assignee: Ciena Corporation
- Current Assignee: Ciena Corporation
- Current Assignee Address: US MD Hanover
- Agency: Young Basile Hanlon & MacFarlane, P.C.
- Main IPC: H03L7/06
- IPC: H03L7/06 ; H03L7/197 ; H03L7/087 ; H03L7/107 ; H03L7/093 ; H03L7/099

Abstract:
Described is a digital fractional phase locked loop (DFPLL) with a current mode low pass filter. The DFPLL includes a binary phase frequency detector (BPFD) configured to output a directional pulse based on comparison of a reference clock and a feedback clock, a current mode low pass filter connected to the BPFD, and a current controlled oscillator (CCO) connected to the current mode low pass filter. The current mode low pass filter configured to output a control current based on at least the directional pulse when a current steering switch directly controlled by the directional pulse switches to the CCO. The CCO configured to adjust a frequency of the CCO based on the control current to generate an output clock. The feedback clock based on the output clock and the reference clock aligned with the feedback clock by adjusting the frequency of the output clock until frequency and phase lock.
Public/Granted literature
- US20210273644A1 APPARATUS AND METHODS FOR DIGITAL FRACTIONAL PHASE LOCKED LOOP WITH A CURRENT MODE LOW PASS FILTER Public/Granted day:2021-09-02
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