Reference design to drive Cree LEDs as standard lamp bulbs

June 13, 2014 // By Graham Prophet
Power Integrations has released a driver reference designs for Cree LED bulbs, representing a simple, reliable drivers that will enable efficient, long-lasting PAR 30 and PAR 38 bulb formats.

A total of four reference designs describe drivers for dimmable PAR 30 and PAR 38 LED light bulbs. Jointly developed by Power Integrations and Cree, the designs use Power Integrations' LYTSwitch-4 driver ICs and CREE MT-G2 EasyWhite LEDs. DER-364 and DER-365 detail low- and high-line PAR 30 LED bulb drivers, respectively, while DER-350 and DER-396 address low- and high-line PAR 38 bulbs. These reference designs are hosted at www.powerint.com/ledrivers/cree

LYTSwitch-4 ICs are highly efficient and deliver accurate output current regulation in bulb and tube replacement applications and high-bay lighting. The devices simplify design and reduce cost while ensuring that lamps deliver uniform light output and perform in TRIAC-dimmable applications. LYTSwitch-4 ICs combine PFC and constant current in a single-stage topology, resulting in power factor greater than 0.95 and typical efficiencies of better than 90%. The single-stage approach also eliminates temperature-sensitive electrolytic bulk capacitors, increasing the bulbs’ reliability and lifetime. LYTSwitch-4 ICs also operate at a high switching frequency (132 kHz), enabling smaller, lower-cost magnetics to be used, while frequency jittering reduces the need for EMI filtering. These factors combine to deliver LED-driver designs that fit easily into space-restricted bulbs.

Designs based on the new drivers meet EN61000-3-2C regulations for total harmonic distortion (THD), and can achieve less than 10% THD. Regulation is better than ±5% across load and production spread, reducing the need for over-design to meet minimum luminance targets and cutting system cost. LYTSwitch-4 drivers deliver dimming performance down to low conduction angles with leading-edge or trailing-edge TRIAC dimmers. Start-up is very fast – typically less than 500 msec even when dimmed to less than 10% light output – and pop-on is virtually eliminated.

Comments Andrew Smith, senior product marketing manager for Power Integrations: “We have worked closely together with CREE to deliver real-world LED lighting systems that live up to their potential, delivering reduced power consumption and increased lifetime. These reference designs enable designers to realize cost-effective, long-lasting