HF AC driving a string of antiparallel laser diodes and LEDS

A lighting system comprising:

• a parallel resonant converter comprising:
• an input node for receiving a bus voltage;
• an output node;
• a half bridge comprising:
• a first switch coupled between the input node and a switching node;
• and
• a second switch coupled between the switching node and a return node;
• a controller adapted to provide a first control signal to the first switch and a second control signal to the second switch;
• an inductor coupled between the switching node and the output node;
• a load coupled to the output node and comprising a first load part, the first load part comprising:
• a first lighting load;
• a capacitor coupled in parallel with the first lighting load;
• and
• a second lighting load coupled in anti-parallel with the first lighting load
• a third lighting load, and
• a fourth lighting load, coupled in anti-parallel with the third lighting load,
• wherein the third lighting load and the fourth lighting load are coupled in series with the first load part, wherein the controller is arranged to control a frequency of the first control signal and the second control signal while keeping a duty cycle of the first control signal and the second control signal constant,
• wherein the third lighting load and the fourth lighting load do not have a capacitor in parallel such that the frequency behavior of the third lighting load and the fourth lighting load are different than of the first lighting load and the second lighting load, or wherein the third lighting load and the fourth lighting load have a capacitor coupled in parallel with a different value compared to the capacitor, such that the frequency behavior of the third lighting load and the fourth lighting load is different than the frequency behavior of the first lighting load and the second lighting load.