L6565D

The STMicroelectronics L6565D is an advanced monolithic current-mode primary controller specifically engineered for quasi-resonant flyback converters. This component enables zero-voltage switching through transformer demagnetization sensing, significantly reducing switching losses and electromagnetic interference. It provides an elite power management solution for high-efficiency AC-DC adapters and consumer electronics.

The L6565D operates with a VCC range up to 18V and features a low start-up current of less than 45 microamps, contributing to ultra-low power consumption. Its output drive capability is 400mA source and 700mA sink. The controller utilizes variable frequency control, operating in Quasi-Resonant mode at high loads for minimal turn-on losses and transitioning to frequency foldback mode at lower loads to maintain efficiency.

Integrated protection circuits, including programmable overvoltage protection and pulse-by-pulse current limiting, make the L6565D a robust choice for safety-critical SMPS designs. The device is housed in an 8-SOIC package and is suitable for surface mount applications. Its proprietary line feed-forward function ensures constant power capability against mains voltage variations, operating across a wide input range from 85V to 265V AC.

Key advantages include elite switching efficiency due to quasi-resonant switching, minimizing EMI and allowing for smaller heat sinks. The ultra-low power consumption is achieved through a low start-up current, enabling high-value start-up resistors. The integrated line feed-forward control ensures consistent output power, and comprehensive protection features enhance system reliability.