Patent ID: 7092260

Claim:
A control circuit for controlling an output voltage of a switched mode power supply, wherein said switched mode power supply comprises a primary-side switch and a transformer with a primary winding, a secondary winding and a secondary-side auxiliary winding, wherein a voltage tapping point is provided between the secondary winding and the auxiliary winding, wherein the control circuit is adapted to be connected to a connection of the auxiliary winding and to said voltage tapping point, wherein the control circuit is adapted to be connected to an output terminal of the switched mode power supply and the output voltage is adapted to be tapped parallel to the secondary winding, and wherein said control circuit comprises: a secondary-side switch for short-circuiting a rectifier diode between said output terminal and said voltage tapping point, and an RC element for providing positive and negative control pulses having a predefined time constant, said RC element being connected in parallel to the auxiliary winding.