Variable frequency oscillator and communication circuit with it
US7592877B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 29, 2007 |
| Grant date | Sep 22, 2009 |
| Priority date | — |
| Expiry date | Jun 29, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K2005/00234
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
In a variable frequency oscillator in a semiconductor device, as the variation of an oscillation frequency caused by the variation of temperature and supply voltage and process variation is large, it is difficult to reduce the conversion ratio of control voltage dependent upon phase noise and the oscillation frequency and therefore, phase noise is large. The variation of the oscillation frequency is suppressed and phase noise is reduced by connecting a voltage-to-current conversion circuit that converts input control voltage to control current of a ring oscillator to the ring oscillator where delay circuits a delay time of which increases and decreases according to the amplitude of input control current are cascade-connected by a plurality of stages in a ring and increasing/decreasing current dependent upon any of temperature, supply voltage and the threshold voltage of a transistor inside the voltage-to-current conversion circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.