Patent ID: 6151509
Filing Date: 2000-11-21
Classification: H03F,H03G,H04B

Abstract:
A cellular phone for a mobile communications system, said cellular phone being operable at a first radio frequency band and a second radio frequency band comprising a dual band transmitter, a power supply and an antenna, said dual band transmitter comprising:a first power amplifier couoled to said power supply, said first power amplifier having a first input for a first signal at said first radio frequency band, a second input for a first control signal, a final amplification stage and a first output for an amplified first signal, said first output being connectable to said antenna;a first detector, said first detector being associated with said power supply and the final amplification stage of said first power amplifier and generating a first detection signal indicative of power drawn by the final amplification stage of said first power amplifier from said power supply when said first power amplifier is active;a second power amplifier coupled to said power supply, said second power amplifier having a third input for a second signal at said second radio frequency band, a fourth input for a second control signal, a final amplification stage and a second output for an amplified second signal, said second output being connectable to said antenna;a second detector, said second detector being associated with said power supply and the final amplification stage of said second power amplifier and generating a second detection signal indicative of power drawn by the final amplification stage of said second power amplifier from said power supply when said second power amplifier is active; anda control module, said control module being associated with said first and second detectors and generating a control signal to control one of said power amplifiers, said control signal being a function of one of said first and second detection signals and a reference signal.