20W LED drivers support TRIAC dimming

March 04, 2016 // By Graham Prophet
LYTSwitch-3 LED driver ICs from Power Integrations operate with a wide range of TRIAC dimmers, in both non-isolated lamp designs and isolated ballast topologies

The LYTSwitch-3 family has been designed to work with bulbs, tubes and downlights up to 20W, and can operate in conjunction with both leading-edge and trailing-edge TRIAC dimmers, with the option of programmable dimming profiles, enabling designers to optimise drivers for dimming range and efficiency. Deep dimming response is also programmable – to extend dimming range or engage the load-shutdown mode to eliminate the possibility of shimmer. When no dimmer is connected or the dimmer is set at full conduction angle, the IC’s dimmer management circuitry is turned off, improving efficiency. The driver continuously manages power factor, including when in dimming mode, which minimises apparent power draw (VA) as the bulb dims, preventing power quality excursions in large installations. LYTSwitch-3 ICs also include a thermal-foldback feature that automatically dims the light output to compensate for inadequate fixture cooling or high ambient temperatures, preventing damage and increasing lamp lifetime.


The company adds that the ICs can be used to provide buck, boost, buck-boost, tapped-buck, tapped-buck-boost and isolated flyback topologies. They are compatible with the widest range of dimmers and provide a choice of MOSFET breakdown voltages for optimised designs. This means that multiple single-sided, ultra-small designs can be based around one IC, reducing design cycle time and part inventory.


With power factor of greater than 0.9 and THD of less than 10%, LYTSwitch-3 driver ICs meet all international efficiency standards including EN61000-3-2, CEC Title 20, CEC Title 24 and ENERGY STAR. The ICs also provide 3% constant-current (CC) accuracy over load, line and from device to device, and are priced at $0.53 (10,000).


A reference design, DER-512, is available for download.


Power Integrations; www.power.com