Diode recovery current suppression circuit

There are many known methods for diode recovery current suppression. Most of them have limited application-they can work only on certain types of power converters. Other known solutions work only in cases of certain input and/or output conditions. Many involve complex circuits and active devices. In this paper, a simple efficient way to suppress recovery diode current is shown. It allows higher frequency power conversion and a lower level of noise. It can be applied in a wide range of DC/DC converter topologies. Achieving the above is possible with passive components only. A circuit is shown which forces the current to alternate its path between two diodes in such a way that each of them has a low dI/dt rate. The sum of the two diodes currents is equivalent to the normal current that would flow without the suppression circuit. This circuit can be used to suppress diode recovery current in most switch mode power converters. For example, it suppresses recovery current through a hard-switched boost PFC diode very effectively allowing a higher conversion frequency and lower level of EMI to be achieved. The circuit can also be used also with buck regulators. Even fly-back circuits working in the continuous mode can benefit from this circuit. It can be applied in secondary rectifier configurations such as full bridge, half bridge and center-tap transformer rectifiers.