Autozeroing floating gate amplifier
US5875126A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 26, 1996 |
| Grant date | Feb 23, 1999 |
| Priority date | — |
| Expiry date | Sep 26, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10B69/00
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An autozeroing floating-gate amplifier (AFGA) is an integrated continuous-time filter that is intrinsically autozeroing. It can achieve a highpass characteristic at frequencies well below 1 Hz. In contrast with conventional autozeroing amplifiers that eliminate their input offset, the AFGA nulls its output offset. The AFGA is a continuous-time filter; it does not require any clocking. The AFGA includes at least one floating-gate MOS transistor that is capable of hot-electron injection of electrons onto the floating gate of the MOS transistor. Electrons are continuously removed from the floating gate(s), for example, via Fowler-Nordheim tunneling. The AFGA has a stable equilibrium for which this tunneling current is balanced by an injection current of equal magnitude. When the circuit is driven away from its equilibrium by an input or something else, an imbalance between the tunneling and injection current charges (if the tunneling current exceeds the injection current) or discharges (if the injection current exceeds the tunneling current) the floating gate(s) until the equilibrium is re-established. The equilibrium is chosen to achieve a desired baseline of operation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.