STMicroelectronics' HVLED101 90-400V flyback controller for LED lighting applications up to 180W improves performance and simplifies design through broad feature integration, patented control techniques and support for primary sensing regulation.
Joining ST's HVLED family of high power factor drivers, the HVLED101 contains 800V initiating circuitry that reduces LED on time to less than 250ms. High voltage input detection circuitry and a maximum power control (MPC) mechanism are also integrated to ensure consistent power output as line voltage fluctuates.
This allows designers to choose smaller, lower-cost external passive components to handle worst-case line conditions. Regulation of primary detection without isolated feedback further reduces the bill of materials and increases reliability.
Among patented innovations, ST's input current shaping algorithm reduces total harmonic distortion (THD) and maximizes power factor. Additionally, the HVLED101 is the first high power factor flyback controller to implement ST's new valley locking technique to minimize audible noise, improve regulation and reduce distortion. At steady state in near-resonant operation, valley locking fixes the number of valleys skipped until a significant change in output power or input voltage is detected.
Together, current building and valley locking improve power factor and THD even at low and medium loads. Flyback converters controlled with the HVLED101 can achieve 5% THD at full load and 10% at 1/3 load to meet key eco-design codes.
Additionally, designers can program the delay time after zero-crossing detection in pure quasi-resonant operation using an external resistor. By ensuring the gate is activated at the lowest point in the valley, the HVLED101 minimizes energy losses and electromagnetic emissions (EMI). Overall, HVLED101 allows converters to achieve maximum efficiency above 90% and no-load power below 100mW.
All necessary protection is built in, including overcurrent protection, input overvoltage protection and power outage protection. There is also an intelligent Auto Recharge Timer (ART) that allows lock-free operation of all protection mechanisms to ensure high reliability and a superior consumer experience.