Patent ID: 7012819

Claim:
A method for operating a switching converter which has input terminals coupled to receive an input voltage, output terminals, a series circuit comprising an inductive energy storage element and a switch driven in clocked fashion, said series circuit being coupled to the input terminals, and a rectifier circuit which couples the inductive energy storage element to the output terminals, and in which a control signal dependent on an output voltage at the output terminals is generated, the method comprising: selectively operating the switching converter in a free-running operating state in which a switch-on duration of the switch is dependent on the control signal during a drive period during which the switch is closed and opened at least once, and in which the switch is switched on again after a drive period in a manner dependent on a magnetization state of the inductive storage element; selectively operating the switching converter in a fixedly clocked operating state in which a switch-on duration of the switch is dependent on the control signal during a drive period during which the switch is closed and opened at least once, and in which the switch is switched on again after a drive period in a manner dependent on a clock signal with a predetermined frequency, and transitioning from the free-running operating state to the fixedly clocked operating state dependent on the magnetization duration of the inductive storage element during a drive period.