CMOS class AB folded cascode operational amplifier for high-speed applications
US7176760B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Mar 31, 2005 |
| Grant date | Feb 13, 2007 |
| Priority date | — |
| Expiry date | Aug 5, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2203/45366
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An operational amplifier (1A or 1B) includes a translinear transconductance stage (2B or 2C) receiving an input signal (Vin) of the operational amplifier and operative to produce a first current (ID18) having a square-law relationship to the input signal (Vin) and a folded cascode operational amplifier (3B) including a differential input stage coupled to receive the input signal (Vin), a folded cascode stage coupled to the differential input stage, and a class AB output stage (45) coupled to the folded cascode stage. The differential input stage includes a tail current source (34) coupled to the translinear transconductance stage and operative to produce a square-law tail current (ID34) scaled to the first current (IDI8) to provide a substantially constant input transconductance for a relatively large range of magnitudes of the input signal (Vin).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.