High-performance low-noise charge-pump for voltage controlled oscillator applications
US6825730B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Mar 31, 2003 |
| Grant date | Nov 30, 2004 |
| Priority date | — |
| Expiry date | Mar 31, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L7/0896
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A charge-pump and a method are provided for conditioning the phase detector output in a phase-locked loop (PLL). The method comprises: accepting a pair of differential phase detector (PD) output signals (up/upb and dn/dnb); connecting each pair of differential PD outputs to first and second charge-pump differential sections; supplying differential charge-pump outputs (Vout+/Vout−) in response to the pair of differential PD output signals; and, disconnecting the charge-pump differential section outputs from the loop filter inputs when the PD differential outputs (up/dn and upb/dnb) are equal. In some aspects, supplying differential charge-pump outputs (Vout+/Vout−) in response to the pair of differential PD output signals includes sourcing a first current through the first charge-pump differential section and sourcing a second current through the second charge-pump differential section. Then, the method further comprises maintaining the first current equal to the second current.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.