ON Semiconductor


650V Integrated Power Switch with 100kHz frequency and adjustable current limit for 17W offline flyback converters

Topology: Other
Switching Frequency (min.): 90.00 kHz
Switching Frequency (max.): 110.00 kHz

Original publication on 2011-03-01, revision 1.0.0


The FSL126HR integrates a Pulse Width Modulator (PWM) and SenseFET is specifically designed for highperformance offline Switch-Mode Power Supplies (SMPS) with minimal external components. FSL126HR includes integrated high-voltage power switching regulators that combine an avalanche-rugged SenseFET with a current-mode PWM control block. The integrated PWM controller includes: Under-Voltage Lockout (UVLO) protection, Leading-Edge Blanking (LEB), a frequency generator for EMI attenuation, an optimized gate turn-on/turn-off driver, Thermal Shutdown (TSD) protection, and temperaturecompensated precision current sources for loop compensation and fault protection circuitry. The FSL126HR offers good soft-start performance. When compared to a discrete MOSFET and controller or RCC switching converter solution, the FSL126MR reduces total component count, design size, and weight; while increasing efficiency, productivity, and system reliability. This device provides a basic platform that is well suited for the design of cost-effective flyback converters.


  • Internal Avalanche-Rugged SenseFET (650V)
  • Under 50mW Standby Power Consumption at265VAC, No-load Condition with Burst Mode
  • Precision Fixed Operating Frequency withFrequency Modulation for Attenuating EMI
  • Internal Startup Circuit
  • Built-in Soft-Start: 20ms
  • Pulse-by-Pulse Current Limiting
  • Various Protections: Over-Voltage Protection(OVP), Overload Protection (OLP), Output-ShortProtection (OSP), Abnormal Over-CurrentProtection (AOCP), Internal Thermal ShutdownFunction with Hysteresis (TSD)
  • Auto-Restart Mode
  • Under-Voltage Lockout (UVLO)
  • Low Operating Current: 1.8mA
  • Adjustable Peak Current Limit


Order Code SPEC Product series Samples
750342371 PDF