A controller for a driver circuit of a solid state lighting (SSL) device is described. The driver circuit comprises a power converter to transfer energy from AC mains voltage to the SSL device. The controller determines a dim level for the SSL device. The controller also determines a synchronization signal by comparing a voltage derived from the input voltage with a pre-determined threshold. The controller determines a sequence of PWM pulses based on the synchronization signal. The controller operates the power converter in a first operation mode for supplying energy to the SSL device at a first energy level within the sequence of PWM pulses, and operates the power converter in a second operation mode in between the PWM pulses. The second energy level is lower than the first energy level and the first energy level and/or a width of the PWM pulses depend on the dim level.