Patent ID: 7894218

Claim:
A switch-mode converter comprising: an inductive energy storage element coupled to a rectifier, providing an output voltage; a switching arrangement configured to receive a control signal that regulates the inductive energy storage element; a controller configured to generate the control signal based on the output voltage, comprising a discrete time band rejection filter and a frequency measuring arrangement; the discrete-time band rejection filter is configured to receive an error signal, which is dependent on the output voltage and is sampled in accordance with a clock signal, and generates a first filter signal on which the control signal is dependent; the frequency measuring arrangement configured to receive the error signal and to ascertain a frequency for a periodic signal component of the error signal and to generate a clock control signal dependent on this frequency; and the frequency measuring arrangement comprising an evaluation circuit, supplied with the sampled error signal or with a signal dependent on this signal and with the clock signal or with a second clock signal dependent on the clock signal, and designed to ascertain a ratio between a period duration for a periodic signal component of the error signal and a period duration for the clock signal.