UCC28911

The UCC28911 is a high-efficiency, primary-side regulated (PSR) flyback controller designed by Texas Instruments for offline power supplies in consumer and industrial applications. It integrates a high-voltage startup circuit and operates without an auxiliary winding, simplifying design and reducing component count. The device supports continuous conduction mode (CCM) operation and features built-in slope compensation to enhance stability across varying load conditions. Core parameters include a wide input voltage range from 85 VAC to 265 VAC, enabling global compatibility with mains-powered systems. It offers accurate output regulation through primary-side sensing, eliminating the need for optocouplers or secondary-side feedback components. This approach improves reliability, reduces cost, and minimizes board space requirements—ideal for compact power solutions such as wall adapters, LED drivers, and small appliances. The UCC28911 incorporates advanced protection mechanisms including overvoltage protection (OVP), under-voltage lockout (UVLO), and thermal shutdown, ensuring safe operation under fault conditions. Its integrated gate driver provides sufficient drive strength for efficient switching of external MOSFETs, while the internal high-voltage start-up circuit ensures reliable turn-on without requiring an external resistor divider. Additionally, the controller supports frequency foldback during light-load conditions to maintain efficiency across the entire load range. Designed for ease of use, the UCC28911 includes programmable soft-start to limit inrush current and reduce stress on components during startup. It also features a fixed-frequency PWM architecture that simplifies EMI filter design and ensures predictable performance. The device’s internal current-limiting feature helps prevent damage from short-circuit events, further enhancing system robustness. Applications span low-to-medium power isolated power supplies where cost-effectiveness, simplicity, and reliability are critical. Common uses include AC-DC adapters, battery chargers, LED lighting systems, and industrial control modules. Its PSR capability makes it particularly suitable for designs requiring minimal external components while maintaining tight output regulation accuracy. Overall, the UCC28911 delivers a robust, high-performance solution for modern power supply designs, combining advanced control features, comprehensive protection, and optimized efficiency—all within a single-chip implementation.