ST Advanced Controller Improves LED Lighting Performance

The new HVLED101 flyback controller from STMicroelectronics is suitable for LED lamps up to 180W. It integrates various functions, patented control technology, and provides primary sensing voltage regulation support, which helps to improve lighting performance and simplifies lamp circuit design.

HVLED101 is a new member of STMicroelectronics' HVLED series of high power factor controllers. It integrates an 800V start-up circuit and can shorten the LED lighting time to less than 250ms. The high-voltage input sensing circuit and Maximum Power Control engine ensure stable power output during mains voltage fluctuations, allowing designers to choose smaller, lower-cost external passive components to handle severe mains conditions. Primary sense regulation without isolated feedback further reduces BOM cost and improves drive circuit reliability.

ST's input current shaping algorithm is a patented innovation that reduces Total Harmonic Distortion and maximizes power factor correction. In addition, the HVLED101 is the first high power factor flyback converter controller using ST's newly developed valley locking technology, which can minimize audible noise, improve voltage regulation performance, and reduce total harmonic distortion.

In the steady state of quasi-resonant operation, valley lock skips the number of valleys until a significant change in output power or input voltage occurs. Current shaping combined with valley locking improves power factor and THD distortion even at low to medium load conditions. The flyback converter controlled by HVLED101 has a THD of 5% at full load and 10% at 1/3 load, which complies with the main eco-design specifications in the world.

In addition, in pure quasi-resonant mode of operation, designers can use external resistors to set the delay time after zero-crossing detection. By ensuring that the gate is turned on at the lowest point of the valley, HVLED101 can minimize energy loss and Electromagnetic Emission. Overall, the HVLED101 enables the converter to achieve a maximum efficiency of more than 90%, while the no-load power is less than 100mW.

The controller has built-in all necessary protection functions, including over-current protection, input over-voltage protection and brownout protection. The smart Auto-Reload Timer (ART) allows all protection mechanisms to operate without lock, ensuring the lamp has excellent reliability and excellent user experience.

In order to help developers accelerate the development cycle and shorten the time-to-market of end products, STMicroelectronics provides two HVLED101 function demonstration boards. EVLHV101PSR50W is a 90-265VAC, 60V/0.8A primary detection regulated isolated flyback converter, and EVLHV101SSR50W is the same design as EVLHV101PSR50W, the difference is the secondary detection regulation. The HVLED101 is available in a narrow SO-14N package and is now in volume production. For more information, please visit the official website.