Differential-type voltage-controlled oscillator with low-frequency stability compensation
US5635878A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 20, 1995 |
| Grant date | Jun 3, 1997 |
| Priority date | — |
| Expiry date | Oct 20, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03B2202/042
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A differential-type voltage-controlled oscillator (VCO) with low-frequency stability compensation is disclosed. The differential-type VCO comprises a voltage-to-current converter for converting an input voltage signal into a biasing current signal to control the frequency of the VCO output. The VCO further comprises a number of stages of differential amplifiers connected in cascade. Each of the stages of differential amplifiers includes a pair of differential input PMOS transistors, with each of the PMOS transistors connected to a pair of NMOS load transistors. Each of the pair of NMOS load transistors are connected in parallel. The VCO further comprises a number of stages of bias circuits connected in cascade. Each of the bias circuits is connected to a corresponding stage of the differential amplifiers for receiving the bias current generated by the voltage-to-current converter. Each of the stages of bias circuits comprises a current source for supplying a constant current to maintain the low-frequency voltage-frequency linearity of the output of the VCO, and a biasing PMOS transistor connected in parallel with said current source.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.