Output voltage driver with transient active pull-down
US4577125A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 22, 1983 |
| Grant date | Mar 18, 1986 |
| Priority date | — |
| Expiry date | Dec 22, 2003 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K19/0136
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An output voltage driver apparatus for an ECL circuit driving a capacitive load is disclosed which comprises an emitter follower means having an output emitter and a reference emitter. The output emitter is connected to the capacitive load. A pull-down transistor means is connected to the output emitter and provides a transient pull-down current for a capacitive load when the output voltage swings from a high level to a low level. A biasing means is connected between the reference emitter of the emitter follower means and the pull-down transistor means so that the pull-down transistor means is biased to turn on when the voltage at the output emitter is higher than the voltage at the reference emitter by a turn-on voltage. Because the capacitive load will hold the voltage of the output emitter higher than that of the reference emitter until the capacitance of the load is discharged, the pull-down transistor means provides a transient pull-down current which speeds up the switching time of the emitter couple logic circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.