Patent ID: 8339817

Claim:
A method of controlling a resonant power converter, the resonant power converter having a switching cycle period and comprising a primary side circuit comprising a first switch and a second switch connected in series and having a half-bridge node therebetween, the primary side circuit being connectable between a supply voltage and a ground, a resonant capacitor forming part of a resonance circuit, and an inductor forming another part of the resonance circuit, the method comprising the steps of: at the start of the switching cycle period closing the first switch for a first period, opening the first switch at the end of the first period and thereafter closing the second switch for a second period, opening the second switch at the end of the second period and thereafter closing the first switch to conclude the switching cycle period, characterised in that the method includes the step of interrupting the second period by opening the second switch at the end of an initial part of the second period, storing energy in the resonant capacitor whilst the second switch is open, and closing the second switch for the remainder of the second period.