Differential amplifier
US4902984A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 23, 1988 |
| Grant date | Feb 20, 1990 |
| Priority date | — |
| Expiry date | Dec 23, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F3/45363
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An improved differential amplifier having circuitry to enhance the slew rate and to provide a means for nulling the offset voltage during fabrication of the amplifier as an integrated circuit. The differential amplifier comprises an input stage connected to a current mirror. A slew rate enhancement circuit injects current into selected points of the circuit when the input voltage exceeds a predetermined threshold. An offset trim circuit injects a selected amount of current into the current mirror to alter the current flow between the input stage and the current mirror, thereby reducing the offset voltage. The selected amount of current is dictated by diodes which may be permanently shorted at various stages during fabrication, both before and after the amplifier is enclosed in an IC package.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.