Pulsed current source to drive high-brightness LED lamps

This paper presents a resonant converter to drive high-brightness light emitting diode (LED) lamps. The resonant converter operates at constant switching frequency, where the control parameter is the phase displacement ψ between the drive signals of each inverter leg. The proposed driver is able to set different patterns of amplitude and pulsewidth modulation (AM and PWM) of the output current to implement the dimming control of the lamp. This control flexibility arises from the wide bandwidth of the resonant converter ensuring an operation free of instabilities and flicker effects. A 120W prototype intended for street lighting applications has been built to validate the design proposal.