Overview
The L6565N is a current-mode primary controller IC designed by STMicroelectronics to build offline Quasi-resonant ZVS (Zero Voltage Switching at switch turn-on) flyback converters. This IC is optimized for high efficiency and compliance with energy-saving standards such as Blue Angel, Energy Star, and Energy 2000. The quasi-resonant operation is achieved through a transformer demagnetization sensing input that triggers the MOSFET's turn-on, ensuring efficient switching and reduced energy consumption.
The device features line voltage feedforward to compensate for power capability variations with mains voltage changes and a frequency foldback mechanism to maintain optimal standby efficiency at light loads. It also includes ultra-low start-up and quiescent currents, a disable function, an on-chip filter for current sensing, and an error amplifier with a precise reference voltage for primary regulation.
Key Specifications
| Parameter | Min. | Typ. | Max. | Unit |
|---|---|---|---|---|
| Supply Voltage (Vcc) | 10.3 | - | 18 | V |
| Turn-on Threshold (VCCOn) | 12.5 | 13.5 | 14.5 | V |
| Turn-off Threshold (VCCOff) | 8.7 | 9.5 | 10.3 | V |
| Hysteresis (Hys) | 3.65 | 4 | 4.3 | V |
| Start-up Current (Istart-up) | 45 | 70 | - | µA |
| Quiescent Current (Iq) | 2.3 | 3.5 | - | mA |
| Operating Temperature (Tj) | -40 | - | 150 | °C |
| Storage Temperature (Tstg) | -55 | - | 150 | °C |
Key Features
- Quasi-resonant (QR) Zero-Voltage-Switching (ZVS) topology
- Line feedforward to deliver constant power vs. mains change
- Frequency foldback for optimum standby efficiency
- Ultra-low start-up (< 70µA) and quiescent current (< 3.5mA)
- Disable function (ON/OFF control)
- 1% precision (@ Tj = 25°C) internal reference voltage
- ±400mA totem pole gate driver with UVLO pull-down
- Pulse-by-pulse & hiccup-mode overcurrent protection (OCP)
- Blue Angel, Energy Star, Energy 2000 compliant
Applications
- TV/Monitor SMPS
- AC-DC adapters/chargers
- Digital consumer devices
- Printers, fax machines, photocopiers, and scanners
Q & A
- What is the primary function of the L6565N IC?
The L6565N is a current-mode primary controller IC designed to build offline Quasi-resonant ZVS (Zero Voltage Switching at switch turn-on) flyback converters.
- How does the L6565N achieve quasi-resonant operation?
Quasi-resonant operation is achieved through a transformer demagnetization sensing input that triggers the MOSFET's turn-on.
- What are the key benefits of the line voltage feedforward feature?
The line voltage feedforward feature compensates for power capability variations with mains voltage changes, ensuring constant power delivery.
- What is the purpose of the frequency foldback mechanism?
The frequency foldback mechanism helps maintain optimal standby efficiency at light loads by automatically lowering the operating frequency.
- What are the typical applications of the L6565N?
Typical applications include TV/Monitor SMPS, AC-DC adapters/chargers, digital consumer devices, and printers, fax machines, photocopiers, and scanners.
- What are the compliance standards for the L6565N?
The L6565N is compliant with Blue Angel, Energy Star, and Energy 2000 standards.
- What is the operating temperature range of the L6565N?
The operating temperature range is from -40°C to 150°C.
- What is the storage temperature range of the L6565N?
The storage temperature range is from -55°C to 150°C.
- What is the start-up current of the L6565N?
The start-up current is less than 70µA.
- What is the quiescent current of the L6565N?
The quiescent current is less than 3.5mA.
