Impact of spread spectrum emi-reduction on audio performance of filterless Class-D amplifiers

In this paper the ability of using spread spectrum clock generation (SSCG) techniques for audio applications is investigated. It is shown how this technique can be used to reduce the electromagnetic emission that is caused by the high frequency switching activity of Class-D audio amplifiers. Additionally the trade-offs when using this technique are explained. Based on measurement and simulation of the conducted common-mode electromagnetic emission and THD+N of a class D audio amplifier, it is shown how the spread spectrum technique can be used to reduce the electromagnetic emission in certain frequency ranges and how it impacts the audio performance.