Patent ID: 8711590

Claim:
A circuit comprising at least one partial circuit for receiving power from an unregulated voltage source having a temporally varying DC output voltage, and for feeding at least one inverter circuit which is adapted to be connected to a transformer, wherein the partial circuit comprises: a voltage doubling circuit; and a voltage regulating circuit with a regulating device, said voltage regulating circuit including: a step-down converter having a first power transistor in a positive branch, a first diode connecting said positive branch and a negative branch, and a first inductance; and a step-up converter, in parallel with said step-down converter, and having a second inductance, a second power transistor connecting a positive branch of said step-up converter and a negative branch thereof, and a second diode in said positive branch of said step-up converter; wherein said step-down converter is arranged directly adjacent to said voltage doubling circuit and said voltage doubling circuit is arranged directly adjacent to said voltage source, and wherein said step-up converter is arranged directly adjacent to said inverter circuit.