Title :
High-efficiency power amplifier using dynamic power-supply voltage for CDMA applications
Author :
Hanington, Gary ; Chen, Pin-Fan ; Asbeck, Peter M. ; Larson, Lawrence E.
Author_Institution :
California Univ., San Diego, La Jolla, CA, USA
fDate :
8/1/1999 12:00:00 AM
Abstract :
Efficiency and linearity of the microwave power amplifier are critical elements for mobile communication systems. This paper discusses improvements in system efficiency that are obtainable when a DC-DC converter is used to convert available battery voltage to an optimal supply voltage for the output RF amplifier. A boost DC-DC converter with an operating frequency of 10 MHz is demonstrated using GaAs heterojunction bipolar transistors. Advantages of 10 MHz switching frequency and associated loss mechanisms are described. For modulation formats with a time-varying envelope, such as CDMA, the probability of power usage is described. Gains in power efficiency and battery lifetime are calculated. An envelope detector circuit with a fast feedback loop regulator is discussed. Effects of varying supply voltage with respect to distortion are examined along with methods to increase system linearity
Keywords :
DC-DC power convertors; MESFET circuits; circuit feedback; code division multiple access; microwave power amplifiers; mobile radio; modulation; power supplies to apparatus; switching circuits; 10 MHz; CDMA applications; GaAs; GaAs HBT; GaAs MESFET power amplifier; RF amplifier; battery lifetime; battery voltage; boost DC-DC converter; distortion; dynamic power-supply voltage; envelope detector circuit; fast feedback loop regulator; high-efficiency power amplifier; linearity; loss mechanisms; microwave power amplifier; mobile communication systems; modulation formats; optimal supply voltage; power efficiency; power usage probability; supply voltage variation effects; switching frequency; system efficiency; system linearity; time-varying envelope; Batteries; DC-DC power converters; Frequency conversion; High power amplifiers; Linearity; Microwave amplifiers; Mobile communication; Power amplifiers; Radiofrequency amplifiers; Voltage;
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
