Complementary differential amplifier with resistive loads for wide common-mode input range
US6252435A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 5, 2000 |
| Grant date | Jun 26, 2001 |
| Priority date | — |
| Expiry date | Oct 5, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2203/45454
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A differential amplifier has a wide common-mode input range since it uses two complementary amplifiers. One amplifier has a differential pair of n-channel transistors while the other amplifier has a differential pair of p-channel transistors. The input range is extended further by replacing the current mirror transistors with load resistors. The load resistors continue to supply current to the differential pair transistors even when the input is within a transistor-threshold of the power or ground rails. The current through the load resistors is mirrored to intermediate mirror transistors that have their gate connected to the resistor's terminal node. Current in the differential amplifiers is mirrored as if current-mirror transistors were present rather than the load transistors. The intermediate mirror transistors supply current to inverse-mirror transistors. Since the inverse mirror transistors are of the opposite type as the intermediate mirror transistors, the inverse mirror transistors continue to operate when the input voltage is in the extreme of the range that shuts off the intermediate mirror transistors. Outputs of the intermediate and inverse mirror transistors of the tw…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.