High-order multipath operational amplifier with dynamic offset reduction, controlled saturation current limiting, and current feedback for enhanced conditional stability
US6002299A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 10, 1997 |
| Grant date | Dec 14, 1999 |
| Priority date | — |
| Expiry date | Jun 10, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2200/81
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An amplifier is disclosed including at least three integrator stages connected to provide a low-frequency path from a signal input to a signal output, and a relatively high-frequency bypass path around the first integrator stage. The first integrator stage uses dynamic offset reduction such as chopper stabilization, and an analog low-pass filter reduces artifacts of the dynamic offset reduction. The paths converge at a current summing node. To prevent instability when the integrators are saturated by large signals, the paths have respective saturation current limits selected so that the relatively high-frequency path is not saturated when the low-frequency path saturates. To ensure that the conditional stability is substantially unaffected by adjustment of closed-loop gain, a current feedback input adjusts the open-loop gain in a fashion inversely proportional to resistance presented to the current feedback input by a feedback circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.