LED driver delivers fast start-up with no pop-on, no dead travel

November 15, 2012 // By Christoph Hammerschmidt
Power Integrations introduced the LYTSwitch product family - an LED driver family which aim at consumer, commercial and industrial lighting applications. The new IC family delivers tight regulation and high efficiency for tube replacements and high-bay lighting, while providing exceptional performance in TRIAC-dimmable bulb applications. Doing away with the necessity for electrolytic bulk capacitors, the driver also contributes to longer operating life for the lighting systems.

LYTSwitch ICs combine PFC and CC into a single switching stage, increasing driver efficiency to more than 90% in typical applications, delivering a power factor greater than 0.95 and easily meeting EN61000-3-2C requirements for total harmonic distortion (THD). Optimized designs deliver less than 10% THD. The combined single-stage converter topology also eliminates high-voltage electrolytic bulk capacitors, leading to greatly extended driver lifetimes even in high ambient temperatures. Accurate primary-side control yields true tight CC performance with better than +/- 5 percent regulation across load, a wide temperature range and production variation enabling tighter design margins and reduced system cost. High switching frequency of 132 kHz means that small, low-cost magnetics can be used in space-constrained bulb applications, while frequency jittering ensures reduced EMI filter requirements. LYTSwitch devices also offer all the usual safety features common to Power Integrations products, including overvoltage, overcurrent and over-temperature protection.

The LYTSwitch family of LED-driver ICs enables better dimming performance when used with leading-edge and trailing-edge TRIAC dimmers even at low conduction angles, complying with NEMA SSL6. Start-up is very fast, typically less than 500 ms, even when dimmed to less than 10% output. Bulbs using LYTSwitch ICs will turn on at almost the same dimming angle as it was at turn-off, virtually eliminating pop-on. Dead band in TRIAC dimming is also eliminated as the LYTSwitch controller ensures that dimming occurs as soon as the dimmer is operated.

Reference designs, including a PAR-38 lamp design developed in partnership with Cree, are downloadable at http://www.powerint.com/en/design-support/reference-designs/design-examples.

The product datasheet and product introduction videos are also available on the Power Integrations website at http://www.powerint.com/products/lytswitch-family/lytswitch.