Communication semiconductor integrated circuit device and wireless communication system
US7242916B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 12, 2006 |
| Grant date | Jul 10, 2007 |
| Priority date | — |
| Expiry date | Sep 12, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L7/193
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
The invention provides a communication semiconductor integrated circuit device (RF IC) capable of pulling in the frequency of a PLL circuit to a desired set frequency at high speed even in the case where a frequency settable range of the PLL circuit is wide without providing a current source other than a current source for charging and discharging in an normal operation. An oscillator as a component of a PLL circuit is constructed so as to be operative in a plurality of bands. In a state where a control voltage of the oscillator is fixed to a predetermined value, an oscillation frequency of the oscillator is measured in each of bands and stored in a storing circuit. A set value for designating a band supplied at the time of PLL operation is compared with the stored measured frequency value. From a result of comparison, a band to be actually used in the oscillator is determined, and a frequency difference between the maximum frequency of the selected band and the set frequency is obtained. Further, a control voltage closest to the set frequency is determined on the basis of the frequency difference and the frequency variable range of the selected band and the control voltage is appl…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.