Electronic ballast for operating at least one first cascade of LEDs

An electronic ballast for operating at least one first cascade of LEDs, comprising:

• an input having a first and a second input connection for coupling to an AC supply voltage;
• a rectifier that is coupled to the first and the second input connection, wherein the rectifier has an output having a first and a second output connection;
• a first unit that comprises the first cascade of LEDs, wherein the first unit is coupled to the first output connection of the rectifier;
• a series circuit comprising an inphase regulator and a shunt resistor, wherein this series circuit is coupled in series between the first unit and the second output connection of the rectifier;
• a setpoint value prescribing apparatus for the inphase regulator having an output that is coupled to the inphase regulator, wherein the setpoint value prescribing apparatus is designed to provide a first setpoint value element at its output, said first setpoint value element being correlated to the voltage between the output connections of the rectifier;
• wherein the setpoint value prescribing apparatus is also designed to provide a second setpoint value element for the inphase regulator, wherein the second setpoint value element is inversely correlated to the peak value of the current through the inphase regulator,
• wherein the setpoint value prescribing apparatus comprises a first voltage divider having a first and a second nonreactive resistor that is coupled between the first and the second output connection of the rectifier, wherein the first setpoint value element is correlated to the voltage drop across the second resistor owing to the current through the first resistor,
• wherein the setpoint value prescribing apparatus comprises an apparatus element for providing the second setpoint value element, wherein the apparatus element has its input coupled to the shunt resistor and its output coupled to the tap of the first voltage divider, wherein the apparatus element is designed to impress a current that is inversely correlated to the peak value of the current through the inphase regulator into the second nonreactive resistor of the first voltage divider.