L6565 Quasi Resonant SMPS Controller IC SMD Package

The L6565 integrates the key functions required for quasi-resonant flyback or forward converter topologies. It operates by detecting the transformer demagnetization signal, ensuring that each MOSFET turn-on occurs at the valley of the drain voltage waveform, drastically reducing switching losses and noise.

The device features a high-voltage startup circuit, eliminating the need for external resistors and reducing standby power. Its frequency foldback function automatically lowers the operating frequency under light-load conditions, improving efficiency at standby or low-power modes.

Additionally, it includes complete protection features such as:

• Overcurrent protection (OCP)
• Overvoltage protection (OVP)
• Undervoltage lockout (UVLO)
• Thermal shutdown (TSD)

The controller drives an external N-channel MOSFET, and its compact SMD package is optimized for low power loss, small form factor, and easy PCB integration.

Features:

• Quasi-Resonant operation for high efficiency and low EMI
• Zero-voltage switching (ZVS) reduces switching losses
• Integrated high-voltage startup circuit (no external resistor)
• Frequency foldback for improved light-load efficiency
• Leading-edge blanking to prevent false triggering
• Built-in protection features:
• Overcurrent (OCP)
• Overvoltage (OVP)
• Thermal shutdown (TSD)
• Undervoltage lockout (UVLO)
• External MOSFET driver with high current capability
• Low standby consumption (< 1W at no load)
• Compact SMD SOIC-8 package for small PCB designs

Applications:

• AC-DC adapters and chargers
• Set-top boxes and LED TVs
• Consumer electronic power supplies
• Battery charger circuits
• Standby and auxiliary power supplies
• Industrial SMPS controllers
• Household appliances and instrumentation

Advantages:

• High efficiency through quasi-resonant ZVS operation
• Low EMI and reduced switching stress on MOSFET
• Compact, reliable, and thermally efficient SMD design
• Low standby power consumption for energy-compliant designs
• Fully protected operation enhances overall system reliability

Package Information:

• Package Type: SMD (SOIC-8)
• Pin Count: 8 pins
• Mounting Type: Surface Mount Technology (SMT)
• Thermal Performance: Low R?JA for improved heat dissipation
• Operating Temperature Range: -40°C to +150°C