INTERMODULATION DISTORTION IN VOLTAGE MODE CLASS D SWITCHING AMPLIFIERS WITH RESISTIVE LOAD

The development of 5G technologies and the Internet of Things lead to a change in the traditional paradigm of frequency-territorial planning. Indeed, in addition to reducing the distance between base stations of cellular communication, there is a problem of approaching the radio means of mobile devices to them, as well as the problem of uncontrolled convergence of an arbitrary number of radio means on mobile devices. In all cases, intermodulation distortion (name in English technical literature: reverse intermodulation distortion - RIMD) occurs between closely spaced simultaneously operating transmitters. Once in the reception band, they disrupt the normal functioning of radio equipment. Therefore, the requirements for the transmitter's electromagnetic compatibility characteristics are continuously tightened. Class D power amplifiers, in addition to higher efficiency and better quality indicators, may potentially have a lower level of intermodulation distortion. The article deals with intermodulation distortion in previously unexplored class D push-pull voltage switching mode power amplifier with a resistive load. On the developed theoretical approach basis, an analysis was made of the intermodulation distortion levels dependence on the electronic components parameters spread and the circuit operating mode. It is shown that in order to achieve the desired levels of intermodulation distortion, not exceeding -70 dB, it is necessary to ensure the difference in the active elements saturation resistances is not more than 20% and the saturation time deviation from the meander is not more than 2 degrees.