Dynamic supply voltage RF power amplifiers for wireless applications

Portable wireless communication has experienced an explosive growth in the last several years which will continue unabated well into the next century. To accommodate this increase, higher output power and increased bandwidths will be required. New systems which offer longer operational time without recharging the battery as well as power amplifiers which offer low distortion will be developed. With the goal of extending battery lifetime in a portable cell phone, this research has extended the concept of driving the power amplifier with dynamically controlled supply voltages, modulated at the optimum level to conserve system power. Generation of voltages was accomplished by using a boost converter technology, which allowed operation from a single 3.6V cell. Total power reduction of over 1.5 times were demonstrated using the dynamic supply voltage topology.; While most switching power supplies available today have a ceiling of 1MHz switching frequency, the boost converter designed for this research was operated at 10MHz to reduce the size of filter components and allow a high bandwidth for CDMA envelope tracking (BW $\approx$ 1MHz). Selection of HBT technology for the power switch significantly reduced AC switching losses due to the high speed devices (ft > 2 GHz) that could be constructed using the AlGaAs system.; To increase linearity in MESFET (MEtal-Semiconductor Field Effect Transistor) amplifiers, a dynamic gate supply was devised which resulted in reduced third order intermodulation products in two tone testing as well as lower adjacent channel power ratios when under CDMA excitation. To investigate the possibility of converter integration, a complete pulse width modulator, driver and power switch were fabricated on wafer. This structure can potentially be co-integrated with the power amplifier itself.; A multi-phase boost topology which operated at 30MHz was constructed and examined with the goal of increasing bandwidth for eventual use in WCDMA applications.; The dynamic power supply amplifier described in this thesis is a promising technique to raise system efficiency and extend battery operating life. In addition, this method may be used as well base stations where power dissipation (and heat removal) is a prime concern.