Method and apparatus to tune and calibrate an on-chip oscillator in a wireless transceiver chip
US6512419B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 14, 2001 |
| Grant date | Jan 28, 2003 |
| Priority date | — |
| Expiry date | Sep 14, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03J2200/10
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A local oscillator calibrator comprises a main charge pump that drives a voltage controlled oscillator (VCO) through a loop filter. A second, replica charge pump can also drive the VCO, but is setup to output only its most positive or most negative analog output control voltage. Since the construction and characteristics of the replica charge pump duplicate the main charge pump, the main charge pump's minimum and maximum analog control outputs can be cloned out to the VCO on demand. A VCO calibration procedure therefore includes switching the VCO to each of its ranges set by a bank of fixed capacitors, and using the replica charge pump to drive the VCO to its minimum and maximum frequency for each range setting. The min-max frequency data is stored in a lookup table, and operational requests to switch to a new channel frequency can be supported with a priori information about which fixed-capacitor range selection will be best.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.