Parallel connected class D amplifiers for RF power source applications
Tadashi Suetsugu, Xiuqin Wei, Tomoharu Nagashima, and Hiroo Sekiya
電子情報通信学会非線形問題研究会, vol.112, no.487, pp.33-36, Mar., 2013. [pdf document]

<Abstract>

This paper researches about influence of multi-frequency 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.