Analysis of a High-Power-Factor Electronic Ballast for High Brightness Light Emitting Diodes

This paper analyzes the performance of a high-power-factor AC-DC converter for the supply of high-brightness light emitting diodes (HBLEDs). The considered topology is a D² one (i.e. a topology that, working in continuous conduction mode, has a voltage conversion ratio that is a function of the duty-cycle squared), working in one of its possible discontinuous modes. No line-frequency energy storage element is used so that the LED current is pulsating at twice the line frequency, with a small high-frequency ripple on top. The impact of such pulsating current supply on LED optical performance and reliability is also evaluated by comparison with standard DC current supply