Complementary current mirror for correcting input offset voltage of diamond follower, especially as input stage for wide-band amplifier
US4893091A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 11, 1988 |
| Grant date | Jan 9, 1990 |
| Priority date | — |
| Expiry date | Oct 11, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F3/3076
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A complementary current mirror includes a PNP transistor and an NPN transistor, one of which serves as a control transistor and the other of which serves as an output transistor. A V.sub.BE voltage generated by forcing a control current into or out of the emitter of the control transistor is imposed between the base and emitter of the output transistor to produce a controlled current in the collector of the output transistor. A first such current mirror, with an NPN control transistor, and a second such current mirror, with a PNP control transistor, are driven by the same control current to supply first and second input bias currents to a diamond follower circuit in the same integrated circuit as the first and second current mirror circuits to face the V.sub.BE voltage of the PNP and NPN transistors of the diamond follower circuit to be equal despite variation in saturation currents of the PNP and NPN transistsors. This results in zero input offset for the diamond follower circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.