| 摘要 |
<p>A power amplifier comprises an input stage having a fully differential amplifier with differential inputs and differential outputs, and a high impedance closed loop common mode feedback control circuit deriving common mode feedback control signals from the differential outputs. The output stage of each differential output of the input stage comprises a class AB amplifier having source followers interfacing with the fully differential amplifier. A common mode output voltage control circuit maintains the common mode output voltage of the class AB amplifiers at a desired level. A quiescent current regulator comprises a circuit for mimicking the behaviour of one of the source followers to derive a control signal for maintaining the quiescent current of the output transistors at a desired value.</p> |
