Power Integrations has a reference design (DER-286) describing a 30 W LED tube replacement ballast power supply which it claims is capable of achieving efficiency levels of over 90% across a wide input-voltage range while meeting worldwide requirements for power factor (PF) and total harmonic distortion (THD).

The DER-286 LED driver reference design is based on the LNK419EG, a member of Power Integrations’ LinkSwitch-PH family of ICs. LinkSwitch-PH devices combine a controller and 725V mosfet for LED-based fluorescent-tube replacements.

The LinkSwitch-PH device performs both PFC and constant-current functions in an advanced single-stage topology, eliminating the need for large, temperature-sensitive electrolytic bulk capacitors, which in turn reduces the size and increases the lifetime of the power supply.

According to Andrew Smith, product marketing manager at Power Integrations, end users prefer the convenience of a single inventory item that can support installations operating from the US residential supply of 90V to 120Vac and also the high nominal voltage 277Vac services of industrial applications.

"This is easy to achieve using LED tubes and ballasts based on the LinkSwitch-PH device,” said Smith.

“EISA regulations due to be implemented in 2012 advance the minimum luminous efficacy of fluorescent tubes, severely challenging the large T12 type and serving notice on T8 and T5 tubes with inefficient older ballasts," said Smith.

The firm says it can offer a more compact and reliable replacement technology.

http://www.powerint.com/sites/default/files/PDFFiles/der286.pdf