| 摘要 |
A power amplifier controller (45) for a wireless communications device (10), such as a wireless telephone, is disclosed. The power amplifier controller (45) has includes controllable bias current sources (56, 58) coupled to Schottky diodes (60), which are coupled to power amplifiers (50) to sense their power output. The controllable bias current sources (56, 58) selectably apply one of multiple available bias currents (I1, I2) to their corresponding Schottky diodes (60F, 60R). Timing and control circuitry (62) in the power amplifier controller (45) receives a desired power level signal (DESPWR), and control switches (SW1, SW2) in the controllable bias current sources (56, 58) to apply a bias current (I1, I2) responsive to the level of power indicated by the desired power level signal (DESPWR). The power detected by Schottky diodes (60F, 60R) is applied to a summing adder (65), from which a control signal (VAPC) is derived and used to control the output of the power amplifiers (50). The controllable bias currents (I1, I2) permit the power output to be selectably sensed with high dynamic range or high sensitivity, depending upon the power level to be applied. <IMAGE> |
