Integrated Controller; 0.25W Auxiliary Power Supply


The FSL3276ALRN is ideal to be configured as a non-isolated high voltage buck switch for low power applications. Its peak current is adjustable down to 70 mA which enables optimum inductor size selection. The modulation control is designed to reduce standby power to 25 mW at 230 VAC input. Though the Pulse Width Modulator (PWM) and SenseFET are ideally integrated for high-performance offline buck, it can also be configured as a buck-boost or non-isolated flyback with minimal external components. This device integrates a high-voltage power regulator that enables operation without an auxiliary bias winding. An internal transconductance amplifier reduces external components for the feedback compensation circuit.

The integrated PWM controller includes: 10 V regulator for no external bias circuit, Under-Voltage Lockout (UVLO), Leading-Edge Blanking (LEB), an optimized gate turnon / turn-off driver, EMI attenuator, Thermal Shutdown (TSD), temperature-compensated precision current sources for loop compensation, and fault-protection circuitry. Protections include: Overload Protection (OLP), Over-Voltage Protection (OVP), Open Feedback Loop Protection (OFLP), and Abnormal Over-Current Protection (AOCP). FSL3276ALRN offers good soft-start performance during startup.

The internal high-voltage startup switch and the Burst-Mode operation with very low operating current reduce the power loss in Standby Mode. As the result, it is possible to reach power loss of 120 mW below (including dummy load: 1 kΩ) without external bias when input voltage is 145 VAC.

  • Built-in Avalanche-Rugged SenseFET: 650 V
  • No-Load Power Consumption: <25 mW at 230 VAC with External Bias; <120 mW at 230 VAC without External Bias
  • Fixed Operating Frequency: 50 kHz
  • Various Protections: Overload Protection (OLP), Over-Voltage Protection (OVP), Open Feedback Loop Protection (OFLP), AOCP (Abnormal Over-Current Protection), Thermal Shutdown (TSD)
  • Fixed 650 ms Restart Time for Safe Auto-Restart Mode of All Protections
  • Pulse-by-Pulse Current Limiting
  • Frequency Modulation for Attenuating EMI
  • No Need for Auxiliary Bias Winding

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Integrated Controller; 0.25W Auxiliary Power Supply





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