Resistorless precharging

The invention relates to resistorless precharging. A boost PFC converter (11) includes a rectifier (12), a converter (13) and an output stage comprising an output capacitor (6) where the DC output voltage (7) is provided across the output capacitor (6). The rectifier includes four rectifying elements connected in a full bridge configuration where the upper two of these four rectifying elements are thyristors (9.1, 9.2) and where the lower two are diodes (9.3, 9.4). In that the thyristors (9.1, 9.2) are controlled such as to be open for only a part of each half period of the input voltage, the amount of current per half period that is passed to the output capacitor (6) is controllable and can be made very small. Accordingly, the charge current for precharging the output capacitor (6) can be controllably limited such that a bulky precharge resistor is not required anymore to avoid high inrush currents.