- Published in issue 12/1993 on page 38
Stereo PWM output amplifier
The most remarkable feature of this small stereo amplifier is the use of a stepper motor bridge driver IC as a stereo power output stage. The circuit diagram shows a three-stage pulse-width modulation (PWM) converter / amplifier for each channel. The left (L) and light (R) audio Input signals are first converted into triangular waveforms by opamps IC1 and IC2.which are wired as integrators, with feedback from the power output stage via resistors R7 and R11.