Low power glitch-free clock switch
US6292044A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 26, 1999 |
| Grant date | Sep 18, 2001 |
| Priority date | — |
| Expiry date | Mar 26, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L7/00
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A glitch-free clock switch circuit for an integrated circuit having a plurality of asynchronous clocks, wherein only one clock is selected at a time, and wherein the clock switching circuitry for switching from a currently selected clock to an inactive clock to next be selected is activated only for the time it takes to complete the switching. The clock switch circuit includes at least three sets of clock drivers, wherein each set is comprised of two drivers and separate clock drivers are each associated with the output clock, the currently selected clock and the clock to next be selected, respectively. An edge detector turns on these clock drivers in response to a clock select signal, and a set of synchronizers receive and synchronize the clock select signal first with the output clock and then with the currently selected clock and the clock to next be selected, respectively. A plurality of logic gates switches the clock output from the selected clock to the clock to next be selected by the clock select signal. A reset circuit turns off the clock drivers once the clock output has been switched from the selected clock to the clock to next be selected. The clock drivers for clocks t…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.