Circuit arrangement for operating n parallel-connected strings having at least one semiconductor light source

A circuit arrangement for operating n parallel-connected strings having at least one semiconductor light source, where n is greater than or equal to 2, the circuit arrangement comprising:

• an input having a first input terminal and a second input terminal for coupling to a DC supply voltage;
• n semiconductor light source units comprising in each case a driver device and an output for coupling to at least one string having at least one semiconductor light source;
• wherein the n semiconductor light source units are coupled in parallel between the first input terminal and the second input terminal, wherein each driver device comprises a PWM controller having a drive output and also a converter, wherein each converter comprises at least one inverter inductance, a converter diode and a converter switch having a control electrode, a working electrode and a reference electrode, wherein the drive output of the respective PWM controller is coupled to the control electrode of the respective converter switch, wherein the output of the respective converter is coupled to the output of the respective semiconductor light source unit, wherein the respective PWM controller is designed to provide a PWM signal at a respectively predefinable frequency to the control electrode of the respective converter switch;
• and
• n current measuring devices which are designed and arranged for measuring the current through a respective one of the n strings having at least one semiconductor light source, wherein each current measuring device is coupled to the respectively associated driver device;
• and
• a control device having n control outputs, wherein each PWM controller has a clock input, wherein a respective control output is coupled to a respective clock input of the n PWM controllers, wherein the control device is designed to provide n clock signals at its n control outputs, said clock signals being phase-shifted by 360°/n with respect to one another.