True/complement output bus for reduced simulataneous switching noise
US5874833A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 3, 1997 |
| Grant date | Feb 23, 1999 |
| Priority date | — |
| Expiry date | Feb 3, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K19/00346
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A true/complement integrated circuit device is disclosed for reducing an amount of simultaneous switching on a bus between a current state and a next state. The device includes a current state register connected to the bus for outputting the current state onto the bus during a first clock cycle. A next state register is provided for containing the next state, wherein the next state is a pending state of the bus intended for a next clock cycle. A comparison circuit compares a current state value in the current state register with a next state value in the next state register on a bit-by-bit basis to determine if the current state value and the next state value are of a same polarity or of an opposite polarity. A circuit is provided for determining a ratio of switching signals from an output of the bit-by-bit comparisons by the comparison circuit. The ratio determining circuit further generates a true/complement (T/C) signal having a first state if it is determined that more than a prescribed percentage of bits are in transition, the T/C signal having a second state otherwise. Lastly, a circuit is provided for complementing the bits of the next state register in response to the T/C s…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.