Amplifiers – With semiconductor amplifying device – Including differential amplifier
Reexamination Certificate
2008-01-29
2010-11-30
Nguyen, Patricia (Department: 2817)
Amplifiers
With semiconductor amplifying device
Including differential amplifier
C330S295000, C330S009000
Reexamination Certificate
active
07843264
ABSTRACT:
An amplifier with accurate input offset voltage is described. In one design, the amplifier includes first and second unbalanced differential pairs. The first unbalanced differential pair receives a differential input signal and provides a first differential current signal. The second unbalanced differential pair receives a differential reference signal and provides a second differential current signal, which is subtracted from the first differential current signal to obtain a differential output signal. The second differential current signal tracks an error current in the first differential current signal so that the differential output signal is zero when the differential input signal is equal to a target input offset voltage for the amplifier. For each unbalanced differential pair, one transistor is M times the size of the other transistor, with M being selected to obtain the target input offset voltage.
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Dang Vannam
Davierwalla Anosh B.
Lee Chul Kyu
Mobarhan Ramin
Nguyen Patricia
QUALCOMM Incorporated
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