Amplifiers – With semiconductor amplifying device – Including differential amplifier
Patent
1991-02-27
1992-07-14
Mottola, Steven
Amplifiers
With semiconductor amplifying device
Including differential amplifier
381121, H03F 345
Patent
active
051306662
ABSTRACT:
The preamplifier includes a first amplifier stage (M1A, M2A) and a second amplifier stage (M1, M2), both of which are of the differential type, have the same dimensions, have their output nodes connected in parallel to one another, and drive a load formed by a current mirror (M3, M4). A third differential amplifier stage with single-ended output (M6, M7, M8, M9, M10, M11) driven by the current mirror supplies the final output voltage of the preamplifier. The input nodes of the first stage act as input for the differential signal to be amplified, and the input nodes of the second stage are driven respectively by a preset reference voltage (V.sub.CM) and by a voltage (V.sub.x) which is proportional to the final output voltage of the preamplifier. A negative voltage-current feedback is thus obtained, due to the fact that a difference in current is generated between the respective output nodes of the first and second stages; the difference is proportional to the difference between the differential signal to be amplified and the difference between the reference voltage and the voltage which is proportional to the final output voltage (V.sub.x -V.sub.CM).
REFERENCES:
patent: 3944944 (1976-03-01), Ellenbecker
patent: 4742308 (1988-05-01), Banu
patent: 4797631 (1989-01-01), Hsu et al.
Krabbe, "A High Performance Monolithic Instrumentation Amplifier", 1971 IEEE International Solid-State Circuits Conference, pp. 186, 187, and 205.
Wurcer et al, "A Programmable Instrumentation Amplifier for 12-Bit Resolution Systems", IEEE Journal of Solid-State Circuits, vol. SC-17, No. 6, pp. 1102-1111 (Dec. 1982).
Gray, "Basic MOS Operational Amplifier Design: An Overview", Department of Electrical Engineering and Computer Sciences of the University of Calif., Berkleley, California, pp. 28-49 (1980).
Mottola Steven
SGS--Thomson Microelectronics S.r.l.
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