PLL charge pump with reduced coupling to bias nodes
US8330511B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 20, 2010 |
| Grant date | Dec 11, 2012 |
| Priority date | — |
| Expiry date | Oct 28, 2030 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L7/0896
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A charge pump includes an UP current mirror and a DN current mirror. The UP current mirror is controlled by an input UP signal and supplies charge onto an output node. The DN current mirror is controlled by an input DN signal and draws charge from the output node. The input UP and DN signals may be received from a phase detector in a Phase-Locked Loop (PLL). To prevent disturbances on bias nodes of the UP and DN current mirrors that otherwise might occur, replica circuits of portions of the UP and DN current mirrors are provided. Each replica circuit is coupled to a bias node of a corresponding current mirror, but is controlled by an input signal of opposite polarity to the input signal that controls the current mirror so that the replica circuit creates disturbances that tend to counteract disturbances created by switching of the current mirror.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.