Dynamic bias for rf power amplifiers

Abstract

A radio frequency power amplifier control circuit amplifies a radio frequency input signal to produce an output signal and a current mirror performs a dynamic bias control by maintaining the radio frequency amplifier operating with a linear amplifier gain.

1 . A radio frequency power amplifier control circuit having dynamic bias control, comprising:
 a radio frequency power amplifier including at least one gain stage configured to amplify a radio frequency input signal to produce a radio frequency output signal; and   a current mirror configured to perform dynamic bias control for each gain stage such that a bias control current signal is produced in direct correspondence with the radio frequency output power; and the current mirror further configured to maintain the radio frequency amplifier operating with a linear amplifier gain.   
   
   
       2 . The radio frequency power amplifier control circuit as in  claim 1 , wherein the current mirror is further configured to receive a variable power control signal to change the radio frequency output power. 
   
   
       3 . A subscriber unit comprising the radio frequency power amplifier control circuit according to  claim 2 , wherein the variable control signal is a transmit power control signal received from a base station in a wireless communication for a reverse channel power control. 
   
   
       4 . The subscriber unit as in  claim 3 , wherein the control mirror further comprise a converter configured to process the transmit power control signal with a converted radio frequency input signal, whereby the converter performs a weighting of the transmit power control signal and the converted radio frequency input signal according to design specific constants which are a function of a dynamic power control range of the radio frequency power amplifier and the radio frequency input waveform peak-to-average ratio, such that the converter produces a current signal. 
   
   
       5 . The subscriber unit as in  claim 4 , wherein the control mirror is configured for receiving the current signal and a feedback from the RF output signal and for comparing the current signal with the feedback to produce the bias control signal.