Controlled push=pull audio amplifier

摘要

The amplifier includes an output transformer (TR) with an output coil (NL) and a negative feed coil (NTS). The end stage transistors (T1,T2) are of N-channel MOSFET type and incorporated between the divided (ND, NS) driver coils (N1,N2). The operating points of the driver coils are achieved by using longitudinal resistors (RG3) and a temperature coupled reference (Ref 1). The operating points are connected in a dynamic negative feedback via a resistor (RD) and a capacitor (CD) in series and are controlled by push-pull signals (Aus A,B) via the gate resistors (RG1,RG2) and capacitors (CG). Source resistors (RS) equalise different characteristics of the end stage transistors. A support capacitor (CST1) keeps the inner resistance of the unipolar feed voltage low. The control stage is specified.