FSL3276ALR: Green Mode Fairchild Buck Switch

The FSL3276ALR integrate Pulse Width Modulator (PWM) and SenseFET is specifically designed for high-performance offline buck, buck-boost, and non-isolation flyback Switched Mode Power Supplies (SMPS) with minimal external components. This device integrates a high-voltage power regulator that enables operation without 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 turn-on / 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). FSL3276ALR 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 without external bias and 25 mW with external bias when input voltage is 230 VAC.

Features

• Built-in Avalanche Rugged SenseFET: 650 V
• Fixed Operating Frequency: 50 kHz
• No-Load Power Consumption: < 25 mW at 230 V_AC with External Bias; <120 mW at 230 V_AC without External Bias
• No Need for Auxiliary Bias Winding
• Frequency Modulation for Attenuating EMI
• Pulse-by-Pulse Current Limiting
• Ultra-Low Operating Current: 250 µA
• Built-in Soft-Start and Startup Circuit
• Adjustable Peak Current Limit
• Built-in Transconductance (Error) Amplifier
• 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