Pulsed current source with active control of the on-time current for LED lamp driver applications

This paper presents a simplified envelope model to study the dynamics of a phase-controlled resonant converter suitable to drive light emitting diode (LED) lamps. The approximate closed form of the transfer function is obtained from the proposed reduced-order model. The fast dynamics of the resonant converter allows us implementing a pulsed current source with active control of the on-time-current free of instabilities and flicker effect with a type II or integral-single-lead controller. A 120W prototype intended for street lighting applications has been built to validate the study. This work is sponsored by the Spanish Ministry of Science and the EU through the project CICYT-FEDER- TEC2011- 23612: “Power conversion with new digital control techniques and soft-saturation magnetic cores”.