Amplifiers – With semiconductor amplifying device – Including differential amplifier
Reexamination Certificate
2005-03-15
2005-03-15
Nguyen, Patricia (Department: 2817)
Amplifiers
With semiconductor amplifying device
Including differential amplifier
C330S133000
Reexamination Certificate
active
06867650
ABSTRACT:
A variable gain amplifier circuit (100) that may have a gain exponentially changed has been disclosed. A variable gain amplifier circuit (100) may include a first OTA (Operational Transconductance Amplifier) (11) and a second OTA (12). A first OTA (11) may receive a differential voltage at input terminals (IN1and IN2). A second OTA (12) may receive an output from a first OTA (11) and may provide a differential output voltage at output terminals (OUT1and OUT2). A second OTA (12) may have second OTA input terminals and second OTA output terminals commonly connected to output terminals (OUT1and OUT2). A small-signal transconductance of the first and second OTAs (11and12) may be proportional to driving currents. A first OTA (11) may have a driving current of I0{1+tan h(x/a)} and a second OTA (12) may have a driving current of I0{1−tan h(x/a)}, where −1<x<1 and a is a constant. In this way, a variable gain amplifier circuit (100) may operate at a low voltage, with a small circuit current, and with essentially no temperature dependence.
REFERENCES:
patent: 5581212 (1996-12-01), Huang et al.
patent: 5757230 (1998-05-01), Mangelsdorf
patent: 5815039 (1998-09-01), Kimura
patent: 5880631 (1999-03-01), Sahota
patent: 5886579 (1999-03-01), Mangelsdorf
patent: 6201443 (2001-03-01), Tanji
patent: 6278321 (2001-08-01), Franck
patent: 6657488 (2003-12-01), King et al.
patent: 2280073 (1995-01-01), None
patent: 4-109705 (1992-04-01), None
patent: 05-114836 (1993-05-01), None
patent: 2000-68761 (2000-03-01), None
Japanese Office Action of Jun. 8, 2004.
English Translations of the indicated portions of the above-referenced Japanese Action.
“A 3.3-V CMOS Wideband Exponential Control Variable-Gain-Amplifier” IEEE 1998.
United Kingdom Combined Search and Examination Report, Sep. 2, 2003.
Wittlinger, Hal, “Applications of the CA3080 High Performance Operational Transconductance Amplifiers”, Intersil Corporation, 2002.
Grise, W., “Application of the Operational Transconductance Amplifier (OTA) to Voltage-controlled Amplifiers and Active Filters”, Internet: http://et.nmsu.edu/˜etti/winter98/electronics/grise/wrg.html.
NEC Electronics Corporation
Nguyen Patricia
Sako Bradley T.
Walker Darryl G.
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