Investigation of switching frequency variations in self-oscillating class D amplifiers

Dennis Nielsen, Arnold Knott, Gerhard Pfaffinger, Michael A. E. Andersen

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Class D audio amplifiers have gained significant influence in sound reproduction due to their high efficiency. One of the most commonly used control methods in class D amplifiers is known as self-oscillation. An parameter of key interest in self-oscillating class D amplifiers is the switching frequency, which can be directly related to the performance of the amplifier. This paper will clearify the myth of the switching frequency through investigation of its dependency on modulation index and reference frequency. Validation is done using simulations and an 50 W amplifier providing 0.2 % of distortion. The switching frequency is tracked through accurate spectrum measurements, and very good compliance with simulation results are observed.
Original languageEnglish
Title of host publicationProceedings of the AES 37TH INTERNATIONAL CONFERENCE
Number of pages8
Publication date2009
Publication statusPublished - 2009
Event37th International AES Conference - Hillerød, Denmark
Duration: 28 Aug 200930 Aug 2009
Conference number: 37


Conference37th International AES Conference
Internet address


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