Study of the Asymmetrical Half Bridge Flyback Converter as an Effective Line Fed Solid State Lamp Driver

The paper illustrates the design and experimental test of a line fed, solid state lamp driver based on the asymmetrical half bridge (AHB) flyback converter. The favorable converter’s characteristics, in terms of soft-switching range and circuit complexity, allow it to operate at variable switching frequency in the range 300-450 kHz, supplying 6W to the load with good efficiency. The considered lamp is made up of 5 series connected high power LEDs (Cree XR-E) and is supplied with 350 mA closed loop regulated, constant current. While presenting similar complexity and overall efficiency with respect to a conventional driver, thanks to an original feedforward control technique that allows to shrink the input filter capacitor, the proposed circuit allows a significant volume reduction and consequent power density improvement