Amplifiers – With semiconductor amplifying device – Including differential amplifier
Reexamination Certificate
2000-01-28
2002-12-03
Pascal, Robert (Department: 2817)
Amplifiers
With semiconductor amplifying device
Including differential amplifier
C330S257000, C330S260000
Reexamination Certificate
active
06489847
ABSTRACT:
BACKGROUND
The present invention is related generally to radio communication devices and, more particularly, to the improvement of distortion characteristics of amplifiers within the transceivers of radio communication devices.
Selectivity filters have conventionally been used in radio communication device transceivers to enable the transceivers to “tune” to a desired channel while rejecting other adjacent channels. Historically, selectivity filters consisted of discrete RLC components or Surface-Acoustic-Wave (SAW) devices. These types of selectivity filters were generally linear and thus did not significantly contribute to the inter-modulation distortion or 1 dB compression point (P
1
dB) of the overall transceiver. Inter-modulation distortion occurs when two interferers at two adjacent channels generate an inter-modulation component which falls into the selectivity filter band. As is known in the art, the third order intercept (IP
3
) of the filter provides a standard measure of the inter-modulation performance of the circuit. The 1 dB compression point (P
1
dB) represents a measure of the linearity of the filter and is the point at which the difference between measured output power from the filter is 1 dB below what would be expected due to a corresponding increase in input power to the filter.
Recently, selectivity filters such as Intermediate Frequency (IF) filters, along with associated driving amplifiers, have been relocated onto the same Application Specific Integrated Circuit (ASIC) as other transceiver circuitry. Integrated IF amplifier and filters, however, generally have degraded distortion performance. An IF amplifier
105
driving an integrated IF filter
110
in a conventional integrated transceiver circuit
100
, such as that shown in
FIG. 1
, typically has an IP
3
10-14 dB higher then the. P
1
dB. In the integrated IF filter
110
, however, the difference between IP
3
and P
1
dB can be as high as 20 dB. Therefore, the IF amplifier
105
limits the distortion characteristic of the combination of the IF amplifier
105
and the IF filter
110
. The IF amplifier
105
thus significantly contributes to the overall transceiver distortion. In order to optimize the overall performance of an integrated transceiver, it would therefore be advantageous to reduce the distortion contributed by the IF amplifier which drives the IF filter.
SUMMARY
The above described desirable characteristics and others are provided by the following exemplary embodiments of the invention.
According to one exemplary embodiment of the invention, an amplifier is provided. The amplifier of this exemplary embodiment comprises: a first differential stage that compares a first voltage with a second voltage and generates a first output current; a first current mirror having an input coupled to receive the first output current and an output that supplies a second output current; and a first output transistor having an input coupled to receive the second output current, and an output for supplying a third output current for driving a load.
REFERENCES:
patent: 4749956 (1988-06-01), Torelli et al.
patent: 4897611 (1990-01-01), Laber et al.
patent: 5034700 (1991-07-01), Herrmann et al.
patent: 5144259 (1992-09-01), Yoshida
patent: 5166635 (1992-11-01), Shih
patent: 5172073 (1992-12-01), Fuji
patent: 5302917 (1994-04-01), Concorso
patent: 5475343 (1995-12-01), Bee
patent: 5481213 (1996-01-01), Johnson
patent: 5504458 (1996-04-01), Van Brunt et al.
patent: 5568093 (1996-10-01), Holzer
patent: 5621357 (1997-04-01), Botti et al.
patent: 5734293 (1998-03-01), Gross
patent: 5815040 (1998-09-01), Barbetta
patent: 5900780 (1999-05-01), Hirose et al.
patent: 5929616 (1999-07-01), Perraud et al.
patent: 5990742 (1999-11-01), Suzuki
patent: 5999054 (1999-12-01), Suzuki
patent: 6060940 (2000-05-01), Chiozzi
patent: 6160450 (2000-12-01), Eschauzier et al.
patent: 6163217 (2000-12-01), Matsubara et al.
patent: 6175277 (2001-01-01), Mavencamp
patent: 2 453 538 (1980-10-01), None
patent: WO92/07422 (1992-04-01), None
patent: WO93/16524 (1993-08-01), None
Ernst H. Nordholt, “Design of High-Performance Negative-Feedback Amplifiers,” Table of Contents, ISBN 0-444-42140-8 (vol. 7), Elsevier Scientific Publishing Company, 1983.
Peter M. Stroet, et al., “Realization of a 10 MHZ Integrated Bipolar DECT Band-Pass Filter,” ESSCIRC '97, Southampton, UK, Sep. 16-18, 1997, pp. 244-247.
Wanlop Surakampontorn, et al., “Instrumentation Amplifiers using Operational Transconductance Amplifiers,” International Journal of Electronics, 1991, vol. 71, No. 3, pp. 511-515.
Giuseppe Palmisano, et al., “High-Drive CMOS Current Amplifier,” IEEE Journal of Solid-State Circuits, vol. 33, No. 2, Feb. 1998, pp. 228-236.
Callewaert et al., “Class AB CMOS Amplifiers with High Efficiency”, IEEE Journal of Solid-State Circuits, vol. 25, No. 3, Jun. 1990, pp. 684-691, New York.
Surakampontorn et al., “Instrumentation amplifiers using operational transconductance amplifiers”, International Journal of Electronics, vol. 71, No. 3, Sep. 1, 1991, pp. 511-515, London GB.
Nguyen Khanh Van
Pascal Robert
Telefonaktiebolaget LM Ericsson
LandOfFree
Low distoration driving amplifier for integrated filters does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Low distoration driving amplifier for integrated filters, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Low distoration driving amplifier for integrated filters will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2929605