Inter-connection of parallel connected class D amplifiers operated at different switching frequencies
Yusuke Ishikawa, Ryuta Yamamoto, Hiroyuki Uchiyama, Xiuqin Wei, Hiroo Sekiya, and Tadashi Suetsugu
2010 International Symposium on Nonlinear Theory and its Applications (NOLTA2010), pp.51-54, Sept., 2010. [pdf document]

<Abstract>

This paper researches about influence of multifrequency operation of parallel connected class D amplifiers. It can be seen that variation in dc supply voltage of one amplifier leg does not influence to output waveform of another amplifier leg. However, parallel connection of two amplifiers influences output power of both amplifiers due to change in impedance of output filter. It is proposed to insert decoupling filter to the output of higher frequency amplifier to reduce the coupling. It is shown that decoupling filter successfully improved coupling between amplifiers.