The HT7L5821 is a Power Factor corrected Quasi-Resonant PWM controller for two stage LED power supply systems. Suitable applications could be LED lamps for outdoor street lighting and ceiling lamps for indoor illumination.
The device meets the usual LED lighting requirements for high power, high efficiency and safety. The device can also be used in adapters, switching power supplies as well as constant voltage and constant current output battery charger applications.
This highly integrated power factor corrected Quasi-Resonant PWM controller has an integrated 650V high voltage JFET used in its quick start-up function. It provides excellent and constant current capabilities and with its high level of functional integration reduces the need for large numbers of external components.
Using the integrated transfer mode, it provides an adjustable low cost system with a high power factor output voltage, which can reduce the input current distortion to improve the Total Harmonic Distortion performance. The Quasi-Resonant PWM controller includes functions such as valley detection, green mode and the power compensation to provide better system efficiencies and lower electromagnetic interference.
The device also contains a full series of protection mechanisms such as secondary side open circuit protection, over current protection with a self-recovery function, adjustable over temperature protection and internal over temperature protection by using an external NTC resistor. Additional protection features include over voltage protection for the VCC input and the DET output as well as an AC input voltage Brown-in/out protection, to ensure safe operation.
The device is supplied in a 16-pin NSOP package and has both the advantages of high efficiency and low cost.
