Low-noise preamplifier stage, in particular for magnetic heads
US5150073A · kind A · utility
Inventors
Key dates
| Filing date | Dec 17, 1990 |
| Grant date | Sep 22, 1992 |
| Priority date | — |
| Expiry date | Dec 17, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F3/45479
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A low-noise preamplifier stage, in particular for magnetic heads, which comprises an input stage comprising a differential circuit and a single-transistor output stage, wherein the differential stage has an intrinsic offset voltage, is ground-connectable and can be directly coupled to the magnetic head, the two transistors forming the differential circuit having different bias currents in order to reduce the input equivalent noise, the base terminal of the first transistor of the differential circuit defining an input of the stage which can be connected directly to a terminal of the magnetic head, the other terminal of the head being connected directly to the ground, the base terminal of the other transistor of the different circuit being connected to the intermediate point of a pair of resistors which are mutually connected in series between the single transistor of the output stage and a line at reference voltage, so that the differential stage biases the output with its offset voltage without requiring additional components for this purpose.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.