On the use of a low frequency boost rectifier as a high power factor LED driver

This paper presents a discussion about the use of a low frequency boost pre-regulator as an LED driver. This kind of very simple converter may provide high power factor, low input current distortion and even standards compliance. A mathematical description of relevant equations is provided and an experimental study applied to a low power, low output voltage desktop luminaire is presented. Preliminary results show that it is possible to design a high power factor low cost LED driver with no need of electrolytic capacitors, what may confer an extended lifetime to the lighting fixture. Due to the discontinuous nature of LED current, a decrement of 10% in the luminous efficacy of LED elements has been measured. Moreover, the equipment has featured an efficiency of 59%, mainly due to the required use of a low frequency transformer. Similar low frequency and high power factor LED drivers have been also studied and presented here, and are mainly focused to street lighting applications. In this case no transformers are required at all, what may define much higher converter efficiency.