Patent ID: 8193797

Claim:
An energy converter comprising a switch having a gate and a source and a drain connected to a switch node, an inductor connected between a voltage terminal and the drain and having an associated inductor current, the drain having an associated drain voltage, a driver for providing a drive signal to the gate, and a controller for controlling the driver, the switch being operable by the controller to conduct current between the drain and source during each of a plurality of primary strokes, the controller comprising reference-fixing means for determining a moment Tref which precedes a moment when the drain voltage next has a local minimum by a constant time interval ΔF, the controller being adapted to switch on the switch to commence the (n)th primary stroke at the end of an interval ΔT(n), which interval starts at the moment Tref, and determining means for determining ΔT(n+1) in dependence on ΔT(n) and the drain voltage at the start of (n)th primary stroke.