ABSTRACT
Since the first edition of this book, Class-D amplifiers have increased enormously in popularity. This is because Class-D gives the highest efficiency of any of the amplifier classes, although the performance, particularly in terms of linearity, is not so good. The rapid rate of innovation means that this section of the book is much more of a snapshot of a fast-moving scene than the rest of the material. I do not want to keep repeating ‘At the time of writing’ as each example is introduced, so I hope you will take that as read.
The fields of application for Class-D amplifiers can be broadly divided into two areas; low and high power outputs. The low power field reaches from a few milliwatts (for digital hearing aids) to around 5W, while the high-power applications go from 80W to 1400W. At present there seems to be something of a gap in the middle, for reasons that will emerge.
