A Two-Point Modulation Technique for CMOS Power Amplifier in Polar Transmitter Architecture

A two-point modulation technique is presented that improves the performance of nonlinear power amplifiers (PAs) in polar transmitters. In this scheme, the output amplitude modulation is performed by controlling the current of the PA. The current control technique enables the PA to provide wideband a...

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Bibliographic Details
Published in:IEEE transactions on microwave theory and techniques 2008-01, Vol.56 (1), p.31-38
Main Authors: Shameli, A., Safarian, A., Rofougaran, A., Rofougaran, M., De Flaviis, F.
Format: Article
Language:English
Subjects:
Amplifiers
Amplitude modulation
Applied sciences
Broadband amplifiers
Circuit properties
CMOS
CMOS power amplifier (PA)
CMOS technology
Current control
Design. Technologies. Operation analysis. Testing
Dynamic range
Efficiency
Electric potential
Electric, optical and optoelectronic circuits
Electronic circuits
Electronic equipment and fabrication. Passive components, printed wiring boards, connectics
Electronics
Exact sciences and technology
Integrated circuits
Modulation
nonlinear PA
polar transmitter
Power amplifiers
Power control
Power generation
Radiocommunications
Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
Telecommunications
Telecommunications and information theory
transmitter
Transmitters
Transmitters. Receivers
Voltage
Wideband
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Summary:A two-point modulation technique is presented that improves the performance of nonlinear power amplifiers (PAs) in polar transmitters. In this scheme, the output amplitude modulation is performed by controlling the current of the PA. The current control technique enables the PA to provide wideband amplitude modulation, as well as high power control dynamic range. In addition, the supply voltage of the PA is adjusted based on the output power level. The voltage supply adjustment substantially improves the effective power efficiency of the PA. The voltage supply control is performed using a second-order sigma-delta dc-dc converter, which presents an efficiency of over 95% in its operational range. The PA operates at 900 MHz with maximum output power of 27.8 dBm and power efficiency of 34% at maximum output power. The proposed PA achieves 62-dB power control dynamic range with amplitude modulation bandwidth of over 17.1 MHz. The circuits are fabricated in a CMOS 0.18 mum process with a 3.3-V power supply.
ISSN:0018-9480
1557-9670
DOI:10.1109/TMTT.2007.912012