An apparatus and method for blocking electromagnetic interference, EMI is presented. In particular, the present invention relates to a switched mode power supply provided with an electromagnetic interference protection circuit with low power dissipation. There is provided an adiabatically-switched electromagnetic interference protection circuit. The protection circuit contains a first charge storage element and a second charge storage element. A switching regulator operates with a switching cycle having an on-time and an off-time; and the control signal is arranged to cause a transition between the first mode and the second mode to start during the off-time of a switching cycle of the switching regulator.