SF5539 is a high performance, high efficiency, highly integrated current mode PWM power switch for offline flyback converter applications.  kif嘉泰姆

   In SF5539, PWM switching frequency with shuffling is fixed to 50KHz and is trimmed to tight range. When the output power demands decrease, the IC decreases switching frequency based on the proprietaryη-BalanceTM control to boost power conversion efficiency at the light load. When output power falls below a given value, the IC enters into burst mode and provides excellent efficiency without audio noise.kif嘉泰姆

  The IC can achieve "Zero OCP/OPP Recovery Gap" using SiFirst's proprietary control algorithm. Meanwhile, the OCP/OPP variation versus universal line input is compensated.  kif嘉泰姆

The IC has built-in synchronized slope compensation to prevent sub-harmonic oscillation at high PWM duty output. The IC also has built-in soft start function to soften the stress on the MOSFET during power on period. kif嘉泰姆

   SF5539 integrates functions and protections of Under Voltage Lockout (UVLO), VCC Over Voltage Protection (OVP), Cycle-by-cycle Current Limiting (OCP), Pins Floating Protection, Over Load Protection (OLP), VCC Clamping, Leading Edge Blanking (LEB), etc. kif嘉泰姆

 SF5539 is available in DIP8 packages.kif嘉泰姆