Design of a PA controller for a quad-band cell phone

A controller which was applied in a power amplifier module for a quad-band cell phone was designed and fabricated in this paper. This controller provides the required DC bias voltage of the quad-band amplifier so that the output of the amplifier reaches the specific power level under various battery output. In addition, a decoder circuit was also included. The outputs of the decoder were used to manage switches so that the power amplifier can operate at different frequency bands, DCS or GSM, and modes, transmission or receiving.