Overview
The L6566BH is an extremely versatile current-mode primary controller IC designed by STMicroelectronics. It is specifically tailored for high-performance offline flyback converters, capable of operating off rectified 3-phase input lines or in single-stage, single-switch, input-current-shaping converters (single-stage PFC) that comply with EN61000-3-2 or JEITA-MITI regulations.
This device supports both fixed-frequency (FF) and quasi-resonant (QR) operation modes, allowing users to select the mode based on application needs. It features an externally programmable oscillator, advanced light load management, and a range of protection functions to ensure reliable and efficient operation.
Key Specifications
| Parameter | Description |
|---|---|
| Package | SO16N |
| Operating Temperature | -40°C to 150°C |
| High Voltage Startup | 840 V |
| Quiescent Current | < 3 mA |
| Gate Driver Current | -600/+800 mA |
| Maximum Duty Cycle (FF Mode) | 70% min |
| RoHS Compliance Grade | Ecopack2 |
Key Features
- Selectable multimode operation: fixed frequency or quasi-resonant
- On-board 840 V high voltage startup
- Advanced light load management with controlled burst-mode operation
- Low quiescent current (< 3 mA)
- Adaptive UVLO (Undervoltage Lockout)
- Line feedforward for constant power capability vs. mains voltage
- Pulse-by-pulse Overcurrent Protection (OCP) with shutdown on overload (latched or auto-restart)
- Transformer saturation detection
- Programmable frequency modulation for EMI reduction
- Latched or auto-restart Overvoltage Protection (OVP)
- Brownout protection
- -600/+800 mA totem pole gate driver with active pull-down during UVLO
Applications
- Industrial Switch-Mode Power Supplies (SMPS)
- SMPS running off rectified 3-phase input lines
- Single-stage, single-switch, input-current-shaping converters (single-stage PFC)
- Applications requiring compliance with EN61000-3-2 or JEITA-MITI regulations
Q & A
- What are the primary operation modes of the L6566BH?
The L6566BH supports both fixed-frequency (FF) and quasi-resonant (QR) operation modes.
- What is the maximum duty cycle in fixed-frequency mode?
The maximum duty cycle in FF mode is limited to 70% min.
- How does the L6566BH manage light loads?
The device features advanced light load management with controlled burst-mode operation to keep consumption low and meet energy-saving recommendations.
- What protection functions are included in the L6566BH?
The device includes not-latched input undervoltage (brownout), output OVP (auto-restart or latch-mode selectable), pulse-by-pulse OCP, transformer saturation detection, and internal shutdown for IC overheating.
- What is the purpose of the adaptive UVLO in the L6566BH?
The adaptive UVLO helps minimize issues related to fluctuations of the self-supply voltage due to transformer parasites.
- How does the L6566BH reduce EMI emissions?
The device features programmable frequency modulation to mitigate EMI emissions.
- What is the package type of the L6566BH?
The L6566BH is available in an SO16N package.
- What is the operating temperature range of the L6566BH?
The operating temperature range is -40°C to 150°C.
- What is the quiescent current of the L6566BH?
The quiescent current is less than 3 mA.
- Can the L6566BH achieve zero-voltage switching (ZVS)?
Yes, under certain conditions, the L6566BH can achieve ZVS in quasi-resonant operation.
