Line fed solid state lamp driver based on the asymmetrical half bridge flyback converter

Abstract

The paper illustrates the design and operation 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 softswitching range and circuit complexity, allow it to operate at variable switching frequency in the range 300-450 kHz, supplying 6W to the load. The 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, the proposed circuit allows a significant volume reduction and consequent power density improvement.