Locked loop circuit and method with digitally-controlled oscillator (DCO) gain normalization
US10594323B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 13, 2018 |
| Grant date | Mar 17, 2020 |
| Priority date | — |
| Expiry date | Jul 18, 2038 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L2207/50
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A locked-loop circuit includes a time-to-digital converter (TDC) having a reference clock input and an error input. A digital loop filter receives an output from the TDC representing a difference between the reference clock input and the error input. A digitally-controlled oscillator (DCO) receives an output from the digital filter in the form of output bits. The DCO has a codeword gain associated with a DCO control word. The codeword gain is applied to the output bits received from the digital loop filter. Calibration logic determines a scaling factor based on a process-voltage-temperature (PVT) operating characteristic. The scaling factor is applied to normalize an actual DCO codeword gain to the codeword gain. The DCO includes an output to deliver an output timing signal having a frequency based on the scaling factor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.