A novel approach to high speed digital pulse-formers based on ring oscillators for pwm and class-D applications

摘要

In this paper, a new concept for a high speed, high resolution digital pulse-former is presented. A digital pulse- former basically maps each input data word (sample) into a binary pulse of corresponding width. Such binary pulse-length modulated signals are incorporated in digital class-D amplifiers and pwm applications. In our approach a synchronous digital counter converting the "rough" part of the input sample is combined with a ring oscillator serving as "fine" counter. This hybrid configuration yields a drastically increased resolution while maintaining moderate clock rates. Results of a first discrete implementation of this concept are discussed.