Invention Grant
- Patent Title: Fraction-N digital PLL capable of canceling quantization noise from sigma-delta modulator
-
Application No.: US15471483Application Date: 2017-03-28
-
Publication No.: US10090845B1Publication Date: 2018-10-02
- Inventor: Gagan Midha , Kallol Chatterjee
- Applicant: STMicroelectronics International N.V.
- Applicant Address: NL Schiphol
- Assignee: STMicroelectronics International N.V.
- Current Assignee: STMicroelectronics International N.V.
- Current Assignee Address: NL Schiphol
- Agency: Crowe & Dunlevy
- Main IPC: H03L7/08
- IPC: H03L7/08 ; H03L7/06 ; H03L7/093 ; H03M3/00 ; H03L7/081

Abstract:
A phase locked loop (PLL) circuit disclosed herein includes a phase detector receiving a reference frequency signal and a feedback frequency signal and configured to output a digital signal indicative of a phase difference between the reference frequency signal and the feedback frequency signal. A digital loop filter filters the digital signal. A digital to analog converter converts the filtered digital signal to a control signal. An oscillator generates a PLL clock signal based on the control signal. A sigma-delta modulator modulates a divider signal as a function of a frequency control word. A divider divides the PLL clock signal based on the divider signal, and generates a noisy feedback frequency signal based thereupon. A noise filtering block removes quantization noise from the noisy feedback frequency signal to thereby generate the feedback frequency signal.
Public/Granted literature
- US20180287620A1 FRACTION-N DIGITAL PLL CAPABLE OF CANCELING QUANTIZATION NOISE FROM SIGMA-DELTA MODULATOR Public/Granted day:2018-10-04
Information query