| 摘要 |
<p>A bias control circuit (100) for use with an RF amplifier (102) comprises a detector (112) coupled to the RF amplifier (102) for detecting a signal proportional to the RF amplifier's output signal power level (POUT), a comparator (106), coupled to the detector (112) for comparing the detected signal to a reference (Vref), and an adjustment circuit (108), coupled to the comparator (106) and the RF amplifier (102), for adjusting the amplifier's bias voltage (Vbias) as a function of the comparison in order to control the RF amplifier's quiescent operating point (bias current) and thereby optimize the RF amplifier's operation for selected operating performance characteristics like gain performance, intermodulation performance, and efficiency. In accordance with another embodiment (200), the RF amplifier's quiescent operating point is adjusted as a function of the current drawn by the RF amplifier (202). In accordance with yet another embodiment (300), the RF amplifier's quiescent operating point is adjusted as a function of the RF amplifier's (302) detected input power level (PIN).</p> |
