Susceptibility of integrated circuits to RFI: analysis of PWM current-mode controllers for SMPS

This paper deals with the analysis of the effects of radio frequency conducted interfering signals (RFI) on integrated circuits (ICs). After reviewing the basic results of the susceptibility analysis of operational amplifiers and smart power integrated circuits, the behavior of several pin-to-pin compatible control ICs for PWM current-mode switching power supplies (SMPS) has been tested in the presence of both continuous wave interfering signals (CW) as well as of pulsed noise signals (underground condition). The tested ICs were selected between some common models available on the market. The variations of the primary functional parameters (inner voltage reference, switching frequency, etc.) are evaluated in different test conditions. The paper gives a comparative view of the results, focusing on the key macroscopic effects.