Random binary number generator
US5961577A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 5, 1997 |
| Grant date | Oct 5, 1999 |
| Priority date | — |
| Expiry date | Dec 5, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K3/0231
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A random number generator includes a plurality of fully differential amplifiers (30) configured as a ring oscillator (22). The output of the ring oscillator (22) is input to a comparator/latch circuit (32) for determining the zero crossing for the ring oscillator. The ring oscillator is a self-oscillating structure that has an oscillation frequency with jitter superimposed thereon. This jitter is a result of the internal thermal noise associated with the integrated circuits that are utilized to realize the amplifiers (30). Each of the amplifiers (30) that make up the ring oscillator operate on a substantially constant current and are subsequently isolated from changes in the power supply. As such, the variations in the frequency thereof are caused solely by thermal noise. The comparator/latch circuit (32) is operable to compare the difference on the output of the last stage of the ring oscillator (22) and the output of the comparator/latch (32) is then sampled by a CPU (12) that is operated on a separate master clock (18). This allows the master clock (18), upon which the sample operation is based, to be completely separate from the ring oscillator (22).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.