STMicroelectronics

L4981B

L4981B Description

The L4981B from STMicroelectronics is an Average Current Mode Power Factor Correction (PFC) controller IC, designed for high-efficiency AC-DC power conversion systems. Operating at a switching frequency of 100kHz, it ensures optimal power factor correction with minimal harmonic distortion. The device supports a supply voltage range of 14.5V to 19.5V, making it suitable for a variety of industrial and commercial power supplies. Packaged in a 20-pin DIP (Through Hole), the L4981B is RoHS3 compliant and adheres to REACH Unaffected standards, ensuring environmental and regulatory compliance.

L4981B Features

• Average Current Mode Control: Ensures high power factor (>0.99) and low THD (Total Harmonic Distortion).
• Low Startup Current (100µA): Reduces power consumption during initialization.
• Wide Supply Voltage Range (14.5V–19.5V): Enhances flexibility in power supply designs.
• 100kHz Switching Frequency: Optimizes efficiency and reduces component size in PFC stages.
• Robust Protection Features: Includes overvoltage, undervoltage, and overcurrent protection.
• Through-Hole Mounting (20DIP): Simplifies prototyping and industrial applications.
• RoHS3 & REACH Compliant: Meets stringent environmental and safety standards.

L4981B Applications

The L4981B is ideal for high-performance power supplies requiring active power factor correction, such as:

• Industrial Power Supplies: For machinery, automation, and control systems.
• LED Drivers: Ensures stable and efficient power delivery for high-brightness lighting.
• Server & Telecom PSUs: Enhances energy efficiency in data centers and communication infrastructure.
• Consumer Electronics: Used in high-power adapters and appliances to meet regulatory standards.

Conclusion of L4981B

The L4981B stands out as a reliable, high-efficiency PFC controller for demanding power conversion applications. Its average current mode operation, low startup current, and robust protection features make it superior to basic voltage-mode PFC controllers. While now obsolete, its performance in industrial, telecom, and lighting applications remains noteworthy. Engineers seeking legacy designs or proven PFC solutions may still find value in its specifications and performance.