Low power programmable ring oscillator
US5796313A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 25, 1996 |
| Grant date | Aug 18, 1998 |
| Priority date | — |
| Expiry date | Apr 25, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L3/00
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A novel ring oscillator integrated circuit whose frequency of oscillation is independent of supply voltage, temperature and process technology is described. In addition, the ring oscillator circuit consumes low power and its frequency of oscillation is programmable. The ring oscillator comprises one or more inverter sections cascaded together in series. The output of the final inverter stage is coupled to the input of the first inverter stage. Inserted in the feedback loop is feedback control circuitry which functions to control the start/stop operation of the oscillator. Each inverter section includes a p-channel transistor coupled to a parallel combination of impedance and capacitance, which gives the inverter section asymmetric operating characteristics. This asymmetry helps to achieve a frequency of oscillation independent of supply voltage. A plurality of transistors having predetermined impedance's are coupled in series with the p-channel transistor to form the current limiting impedance. An output buffer provides large drive capability and achieves low power consumption by eliminating normally present crowbar current during switching. Pull-down control circuitry provides ind…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.