Amplifiers – With semiconductor amplifying device – Including differential amplifier
Patent
1996-03-29
1998-03-31
Mullins, James B.
Amplifiers
With semiconductor amplifying device
Including differential amplifier
330258, H03F 345
Patent
active
057342970
ABSTRACT:
A rail-to-rail input stage with constant g.sub.m and constant common-mode output currents is provided. The common-mode output currents are controlled by the use of current switches. When low and high common-mode input voltages are applied to the input stage, the current switches take part of the tail currents of the input stage transistors, divides it into two equal parts, and directs the two equal current signals to the outputs. When intermediate common-mode input voltages are applied, the current switches regulate the tail currents of the input pairs such that the common-mode output current and g.sub.m remains constant. The current switches are responsive to changes in the common-mode input voltages, and thereby maintain the g.sub.m constant.
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patent: 5323120 (1994-06-01), Ryat
patent: 5561396 (1996-10-01), Hogervorst et al.
R. Hogervorst et al, "A Compact Power-Efficient 3V CMOS Rail-to-Rail Input/Output Operational Amplifier for VLSI Cell Libraries", IEEE Intn'l Solid-State Cir. Conf., Session 14, 1994, pp. 244-245.
R. Hogervorst et al, "CMOS Low-Voltage Operational Amplifiers with Constant-g.sub.m Rail-to-Rail Input Stage", Analog Integrated Circuits and Signal Processing 5, 1994, pp. 135-146.
M.D. Pardoen et al, "A Rail-to-Rail Input/Output CMOS Power Amplifier", IEEE Journal of Solid-State Circuits, vol. 25, No. 2, Apr. 1990, pp. 501-504.
J.H. Huijsing et al, "Low-Voltage Operational Amplifier with Rail-to-Rail Input and Output Ranges", IEEE Journal of Solid-State Circuits, vol. sc-20, No. 6, Dec. 1985, pp. 1144-1150.
J.H. Botma et al, "A low-voltage CMOS Op Amp with a rail-to-rail constant-g.sub.m input stage and a class AB rail-to-rail output stage, IEEE, 1993, pp. 1314-1317.
Hogervorst Ronald
Huijsing Johan Hendrik
Mullins James B.
Philips Electronics North America Corporation
Wieghaus Brian J.
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