Electrostatic discharge protection circuit with dynamic triggering
US5311391A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 4, 1993 |
| Grant date | May 10, 1994 |
| Priority date | — |
| Expiry date | May 4, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/0002
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Electrostatic discharge (ESD) protection circuitry having a string of diode-connected field-effect transistors (FETs) connected between a bus and ground plane for triggering a shunt element, such as a large n-channel FET, connected between the same or a different bus and the ground plane. The bus or buses are diode-connected through the base-emitter junction of pnp transistors to signal pads, as well as to a positive voltage power supply. The string of FETs turns on when the pad-to-ground voltage, and thus the bus-to-ground voltage, exceeds a threshold characteristic of an ESD event. The string acts as a voltage divider to bring a node between two of the FETs up to a voltage that will activate an n-channel trigger FET, which is part of a resistive-load inverter. This drives another inverter that in turn drives the shunt FET. When the voltage is pulled back down below the threshold voltage, the shunt FET continues to shunt current to the ground plane for the duration of the ESD event.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.