Input and output buffer circuit
US5880602A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 28, 1996 |
| Grant date | Mar 9, 1999 |
| Priority date | — |
| Expiry date | Feb 28, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K19/00315
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An input and output buffer circuit which is contained in a first circuit operated on a first power source of a first voltage level Vcc1 and is permitted to connect to a second circuit operated on a second power source of a second voltage level Vcc2 higher than the first voltage level Vcc1 including: a driver PMOS transistor with a CMOS gate; a PAD terminal serving as an input and output terminal; and means for controlling the potential of the N well of the driver PMOS transistor in such a manner that when the potential at the PAD terminal is less than Vcc1-Vth, wherein Vth is a threshold voltage of a MOS transistor contained between the driver PMOS transistor and the PAD terminal, the potential of the N well is set at the first voltage level Vcc1; when the potential at the PAD terminal is more than Vcc1+Vth, the potential of the N well is equated with the potential at the PAD terminal; and when the input and output buffer circuit is in the output mode the potential of the N well is switched to the first voltage level Vcc1, whereby the noise resistance and the latch-up resistance of the input and output buffer circuit are improved while preventing a path current flowing through the …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.