Power Integrations, a leading supplier of high-efficiency, high-reliability LED driver ICs, has announced the RDR-347, a new LED-downlight reference design. The circuit demonstrates the capabilities of the recently launched LYTSwitch IC family, which offers high-end dimming performance from a single-stage LED driver- together with efficiency, space and cost benefits that the single-stage approach tends to bring.
The RDR-347 12 W reference design, based on the LYT4313E, delivers a power factor greater than 0.95 and reduces total harmonic distortion (THD) to less than 10% – meeting EN61000-3-2C requirements. The efficiency is greater than 86% at 120 VAC and this performance is possible because LYTSwitch ICs use one combined PFC and CC power conversion stage which minimises losses and cuts component count, which in turn increases reliability and decreases cost.
TRIAC dimming is challenging, especially deep-dimming where TRIAC asymmetry between half-cycles can have a significant effect. However, the RDR-347 shows that the LYTSwitch driver IC works, even at very low output currents, without any shimmer or flicker. The design also demonstrates system start-up without noticeable hysteresis (so-called “pop-on effect”), even in deep-dimming.
The IC features a very fast start-up time (under 500 ms) even when dimmed to 10% output current, achieving the “instant-on” condition that many customers want, but that many designs in the market cannot provide.
According to Andrew Smith, senior product marketing manager for Power Integrations: “By using our LYTSwitch driver, lighting engineers can achieve excellent dimming with minimal efficiency loss.”