| 摘要 |
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 said differential outputs; and an output stage comprising for each differential output of the input stage a class AB amplifier having source followers interfacing with said folded cascode amplifier. A common mode output voltage control circuit maintains the common mode output voltage of the class AB amplifiers at a desired level, and a quiescent current regulator comprising a circuit for mimicking the behaviour of one of the source followers to derives a control signal for maintaining the quiescent current of the output transistors at a desired value.
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