Integrated circuit output buffers having feedback switches therein for reducing simultaneous switching noise and improving impedance matching characteristics
US6242942A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 16, 1999 |
| Grant date | Jun 5, 2001 |
| Priority date | — |
| Expiry date | Aug 16, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K17/164
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Integrated circuit output buffers include pull-down an pull-up circuits and a control circuit that utilizes a preferred feedback circuit to facilitate a reduction in simultaneous-switching noise during pull-down and pull-up operations and also improve the impedance matching characteristics of the output buffers during DC conditions. The preferred feedback circuit also limits the degree to which external noise can influence operation of the control circuit. Each of the pull-down and pull-up circuits may comprise a respective pair of primary and secondary transistors. The pull-down circuit is preferably configured so that the primary and secondary pull-down transistors (e.g., NMOS transistors) are electrically coupled to an output signal line (through an ESD protection resistor) and a first reference signal line (e.g., Vss). The control circuit is designed to activate the pull-down circuit by turning on both the primary and secondary pull-down transistors during a leading portion of the pull-down time interval and by turning off the secondary pull-down transistor during a trailing portion of the pull-down time interval using a first feedback switch that is electrically coupled in ser…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.