LD7591Transition-Mode PFC Controller with Fault Condition Protection

The LD7591 is a voltage mode PFC controller operating on transition mode, with several integrated functions of protection, such as OVP, OCP, and Brown-in protection. It reduces the components counts and is available in a SOP-8 or DIP-8 package. Those make it an ideal design for low cost applications.
It provides functions of low startup current, over voltage protection, open feedback protection, disable function, over current protection, under voltage lockout and integrated LEB of current sensing. Unlike the traditional current mode PFC controller, LD7591 is free from extra rectified AC line voltage information to minimize the power loss.
The LD7591 will be disabled if INV pin voltage falls below 0.45V and the operating current rises over 65μA




  • Transition mode of PFC pre-regulator
  • Voltage mode control
  • Programmable max. on-time
  • Low Startup Current (<30mA)
  • UVLO (Under Voltage Lockout)
  • LEB (Leading-Edge Blanking) on CS Pin
  • Open-Feedback Protection and Disable Function
  • OVP (Over Voltage Protection)
  • OCP (Cycle by cycle current limiting)
  • 800/-1200mA Driving Capability
  • Internal OTP function



  • Adaptor of Output above 65W.
  • Open Frame Switching Power Supply
  • LCD TV Power Supply
  • LED Power Supply