Amplifiers – With plural amplifier channels – Redundant amplifier circuits
Reexamination Certificate
2000-04-28
2001-09-11
Shingleton, Michael B (Department: 2817)
Amplifiers
With plural amplifier channels
Redundant amplifier circuits
C330S051000, C330S129000, C330S295000
Reexamination Certificate
active
06288608
ABSTRACT:
TECHNICAL FIELD
The present invention relates, in general, radio frequency power amplifiers and, in particular, to a radio frequency power amplifier having an improved efficiency and adapted for use in a battery powered handset unit of a wireless communications system.
BACKGROUND OF THE INVENTION
The efficiency of the radio frequency power amplifier used in a battery powered handset unit of a wireless communications system is a major consideration because this power amplifier is the largest power load on the battery. The higher the efficiency of the power amplifier, the longer time use of the battery powered handset without a recharge.
For a J-CDMA power amplifier, the unit should meet the accepted performance standards for power amplifier efficiency, gain and adjacent channel power ratio (ACPR) at full power (i.e., +27 dBm), while providing exceptionally good efficiency at lower power (i.e., +13 dBm).
Typical prior art implementations of 27 dBm to 28 dBm power amplifiers provide gains on the order of 28 dB, power amplifier efficiency on the order of 32% for GaAs MOSFET (Anadigics). It is believed that exotic and costly technologies like GaAs PHMET could achieve 45% to 50% power amplifier efficiency in such prior art configuration at full power.
SUMMARY OF THE INVENTION
It is an objective of the present invention to provide a new and improved radio frequency power amplifier for a battery powered handset unit of a wireless communications system.
It is another objective of the present invention to provide a radio frequency power amplifier for a battery powered handset unit of a wireless communications system that overcomes deficiencies of prior art radio frequency power amplifiers of this type.
To achieve these and other objectives, a radio frequency power amplifier for a battery powered handset unit of a wireless communications system, constructed in accordance with the present invention, includes means for supplying a radio frequency signal, a low power signal path having: a first radio frequency amplifier for amplifying the radio frequency signal and a first control switch for controlling passage of the radio frequency signal through the low power signal path to a first output; and a high power signal path having a second radio frequency amplifier for amplifying the radio frequency signal and a second control switch for controlling passage of the radio frequency signal through the high power signal path to a second output. This radio frequency power amplifier also includes bias and logic means for: (a) controlling the first control switch to permit passage of the radio frequency signal through the low power signal path when the handset is located within a prescribed distance from a base station and prevent passage of the radio frequency signal through the low power signal path when said handset is located outside the prescribed distance from the base station, (b) biasing the first radio frequency amplifier to amplify the radio frequency signal when the handset is located within the prescribed distance from the base station and prevent amplification of the radio frequency signal by the first radio frequency amplifier when the handset is located outside the prescribed distance from the base station, (c) controlling the second control switch to permit passage of the radio frequency signal through the high power signal path when the handset is located outside the prescribed distance from the base station and prevent passage of the radio frequency signal through the high power signal path when the handset is located within the prescribed distance from the base station, and (d) biasing the second radio frequency amplifier to amplify the radio frequency signal when the handset is located outside the prescribed distance from the base station and prevent amplification of the radio frequency signal by the second radio frequency amplifier when the handset is located within the prescribed distance from the base station. This radio frequency power amplifier further includes means for coupling together the first output and the second output.
REFERENCES:
patent: 4598252 (1986-07-01), Andricos
patent: 5256987 (1993-10-01), Kibayashi et al.
patent: 5629648 (1997-05-01), Pratt
patent: 5872481 (1999-02-01), Sevic et al.
patent: 9139711 (1997-05-01), None
Gray, Paul R. and Meyer, Robert G., Analysis and Design of Analog Integrated Circuits, 1993, pp. xiv, 269-343.
Maxim 19-1524; Rev 2; Nov. 1999. 2.7V, Single-Supply, Cellular-Band Linear Power Amplifiers, 16 pp. .
Jadus Dale K.
Moniz James M.
Pusl Joseph
Ruhe Colin
Stuebing Carl
Abate Esq. Joseph P.
International Business Machines - Corporation
Ratner & Prestia
Shingleton Michael B
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