Compensating a Gm-boosted folded-cascode amplifier
US6300831A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 21, 1999 |
| Grant date | Oct 9, 2001 |
| Priority date | — |
| Expiry date | Dec 21, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2203/45676
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A folded-cascode amplifier (30) having a small signal gm being boosted and transferred from the input stage to the output stage to reduce current consumption and expand bandwidth. The amplifier has a pair of second amplifiers (A) operating as boosting amplifiers that provide a pole at its output node, which is at a fairly low frequency. A compensation scheme is employed to introduce a zero to cancel out this pole, and as a side benefit, another zero is brought in which is used to cancel out a second pole of the original folded-cascode amplifier so that bandwidth is actually expanded. Two compensation capacitors (C1, C2) serve two purposes, one, providing a dominant pole to the main amplifier due to a Miller Effect, where the value of the two capacitors are much smaller than for conventional folded-cascode amplifiers, and two, introduce two zeros which cancel out two high frequency poles so that bandwidth is expanded.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.