Fixed-Frequency Flyback Regulator with Self-Supply, Multi-Mode Control and Over-Power Line Compensation

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The HF500-7 is a fixed-frequency, current-mode regulator with built-in slope compensation. The HF500-7 combines a 700V MOSFET and a full-featured controller into one chip for a low-power, offline, flyback, switch-mode power supply.
At medium and heavy loads, the regulator works in a fixed frequency with frequency jittering, which helps spread energy out in a conducted mode. During a light-load condition, the regulator freezes the peak current and reduces its switching frequency to fOSC(min) to offer excellent efficiency at light load. At very light loads, the regulator enters burst mode to achieve low standby power consumption.
Full protection features include thermal shutdown, brown-in and brown-out, VCC under-voltage lockout (UVLO), overload protection (OLP), short-circuit protection (SCP), input and output over-voltage protection (OVP), and over-temperature protection (OTP).
The HF500-7 features timer-based fault detection and over-power compensation to ensure that the overload protection point is independent of the input voltage. The HF500-7 can also be self-supplied without any auxiliary winding to save BOM cost.
The HF500-7 is available in a SOIC8-7B package.


  • 700V/12Ω Integrated MOSFET
  • Fixed-Frequency Current-Mode Control Operation with Built-In Slope Compensation
  • Frequency Foldback Down to fOSC(min) at Light Load
  • Burst Mode for Low Standby Power Consumption
  • Frequency Jittering for a Reduced EMI Signature
  • Over-Power Compensation
  • Internal High-Voltage Current Source
  • Self-Supplied without Auxiliary Winding
  • VCC Under-Voltage Lockout (UVLO) with Hysteresis
  • Programmable Input B/O and Over-Voltage Protection (OVP)
  • Overload Protection (OLP) with a Programmable Delay
  • Latch-Off Protection on TIMER
  • Thermal Shutdown (Auto-Restart with Hysteresis)
  • Short-Circuit Protection (SCP)
  • Programmable Soft Start (SS)
  • Available in a SOIC8-7B Package


  • Vac (min) (V)85
  • fsw (max) (kHz)65
  • Vbr (V)700
  • Vac (max) (V)265
  • VCC (max) (V)24
  • PackageSOIC8-7B
  • TypeRegulator
  • GradeCatalog
  • Control MethodFixed Frequency
  • Power Range DefinedNo