Feedback biasing technique for a stage of an amplifier that uses a feedback control loop having low gain

摘要

According to an aspect of the present invention, a stage of an amplifier contains a positive feedback loop in addition to a negative feedback loop to maintain the bias currents at a desired level in the active components providing the output of the amplifier. The positive feedback loop senses the finite gain (i.e., less than the ideal infinite gain) of the negative feedback loop and compensates for the finite gain. Due to the use of the positive feedback, the duration and extent of deviation of the bias currents from the desired level is reduced, thereby minimizing the distortions in the output of the amplifier. In an embodiment, the stage corresponds to a class AB stage.