Operational amplifier for stably driving a low impedance load of low power consumption
US5285168A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Sep 15, 1992 |
| Grant date | Feb 8, 1994 |
| Priority date | — |
| Expiry date | Sep 15, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L25/028
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An operational amplifier is equipped at its input stage with a folded cascode type differential amplifier and at its downstream stage with pre-buffers, which include a differential amplification stage of PMOS input and a differential amplification stage of NMOS input, as level shifters. A MOS resistor having its gate terminal fed with an intermediate bias potential between a supply voltage V.sub.DD and an earth potential is connected between every one of the drain terminals of current-mirror connected load MOSFETs in the pre-buffers. As a result, the gains of the pre-buffers in the steady state can be suppressed to about 10 dB or less. The individual MOSFETs of the push-pull output stage are individually driven by the pre-buffers of low gains.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.