A method for providing a switch mode power supply output voltage with a flyback circuit driving a series connected string of light emitting diodes, LEDs , wherein the flyback circuit comprises a primary circuit controlled by a main switch and a secondary circuit comprising a synchronous switch coupled in series with a secondary coil of a flyback transformer and an output capacitor (Cout) coupled in parallel with the series connected secondary coil and synchronous switch , said method comprising the steps of: charging the output capacitor (Cout) through the flyback transformer with the main switch , wherein the flyback transformer and the main switch are couplable to a power source; discharging the output capacitor (Cout) through the flyback transformer with the synchronous switch ; wherein the main switch and the synchronous switch are controlled by a switch mode power supply controller , characterized by feeding a dimming control signal to an input (DIM/EN) of the switch mode power supply controller ; wherein the steps of charging and discharging the output capacitor provide a square wave pulse width modulated current to the series connected string of light emitting diodes (LEDs) coupled with the output capacitor (Cout) depending on the dimming control signal by regulating a load current and terminating a pulse width modulated current pulse through said series connected string of LEDs asynchronously, wherein, to eliminate the tail current of the pulse width modulated current pulse, the output capacitor is discharged through a secondary winding of the flyback transformer and the synchronous switch thereby charging an input capacitor (C IN ) coupled with a primary winding of the flyback transformer , wherein to drive the output voltage up, the main switch is controlled and the flyback circuit operates in forward mode and wherein to drive the output voltage down, the synchronous switch is controlled to discharge the output capacitor (Cout). . charging the output capacitor (Cout) through the flyback transformer with the main switch , wherein the flyback transformer and the main switch are couplable to a power source; discharging the output capacitor (Cout) through the flyback transformer with the synchronous switch ; wherein the main switch and the synchronous switch are controlled by a switch mode power supply controller , characterized by feeding a dimming control signal to an input (DIM/EN) of the switch mode power supply controller ; wherein the steps of charging and discharging the output capacitor provide a square wave pulse width modulated current to the series connected string of light emitting diodes (LEDs) coupled with the output capacitor (Cout) depending on the dimming control signal by regulating a load current and terminating a pulse width modulated current pulse through said series connected string of LEDs asynchronously, wherein, to eliminate the tail current of the pulse width modulated current pulse, the output capacitor is discharged through a secondary winding of the flyback transformer and the synchronous switch thereby charging an input capacitor (C IN ) coupled with a primary winding of the flyback transformer , wherein to drive the output voltage up, the main switch is controlled and the flyback circuit operates in forward mode and wherein to drive the output voltage down, the synchronous switch is controlled to discharge the output capacitor (Cout). . <EOS>