High-efficiency LED driver solution with thyristor dimming and active PFC features

The latest LED driver IC product series LYTSwitch can achieve precise voltage regulation and high efficiency in tube replacement applications and high bay lighting, and can also provide excellent performance in thyristor dimming bulb applications. It can be used to design smaller and longer-lasting lighting.
Recently, PI launched its latest LED driver IC product series LYTSwitch, which can achieve precise voltage regulation and high efficiency in tube replacement applications and high bay lighting, while providing excellent performance in thyristor dimming bulb applications.

LYTSwitch IC integrates PFC and CC into a single switching stage, which can increase the efficiency in typical applications to more than 90%, make the power factor greater than 0.95, and easily meet the total harmonic distortion (THD) requirements of EN 61000-3-2C. After the design is optimized, THD can be less than 10%. The integrated single-stage converter topology can also eliminate high-voltage and large-capacity electrolytic capacitors, thereby greatly extending the service life of the driver, even at high ambient temperatures. Precise primary-side control enables the driver to achieve truly strict constant current performance, with a constant current regulation rate better than ±5% (Figure) under different loads, a wider temperature range and manufacturing differences, thereby achieving a tighter design margin and reducing system costs. The high switching frequency of 132kHz means that smaller and lower-cost magnetic cores can be used in space-constrained bulb applications, while frequency jittering also ensures that EMI filter design requirements are reduced. LYTSwitch devices can provide all the common safety features of PI products, including overvoltage, overcurrent and overtemperature protection.

LYTSwitch series LED driver ICs work with leading and trailing edge thyristor dimmers to achieve excellent dimming performance, easily meeting NEMASSL6 standards even at low conduction angles. The driver starts very quickly, typically less than 500 milliseconds, and starts just as quickly even when 10% of the light output is turned on. Bulbs designed with LYTSwitch ICs can be turned on at almost the same dimming angle as when they were turned off, which virtually eliminates the sudden brightness phenomenon. In addition, the dead zone in thyristor dimming is also eliminated because the LYTSwitch controller ensures that dimming is immediately performed when the dimmer starts working.

Using LYTSwitch ICs, smaller and longer-lasting lighting can be designed, and is widely used in consumer bulbs, commercial lighting and T8 tubes, industrial lighting, high bay lights, and outdoor lighting. Accurate constant current performance under different working conditions can greatly simplify design and reduce costs, while ensuring that lighting provides uniform and consistent light output.