The UCC28250 PWM controller is designed for high power density applications that may have stringent pre-biased startup requirements. The UCC28250’s integrated synchronous rectifier control outputs target high efficiency and high performance topologies such as half-bridge, full-bridge, interleaved forward, and push-pull. The UCC27200 half bridge drivers and UCC2732X MOSFET drivers used in conjunction with the UCC28250 provide a complete power converter solution.

Externally programmable soft-start, used in conjunction with an internal pre-biased startup circuit, allows the controller to gradually reach a steady-state operating point under all output conditions. The UCC28250 can be configured for primary or secondary-side control and either voltage or current mode control can be implemented.

The oscillator operates at frequencies up to 2 MHz, and can be synchronized to an external clock. Input voltage feedforward, cycle-by-cycle current limit, and a programmable hiccup timer allow the system to stay within a safe operation range. Input voltage, output voltage and temperature protection can be implemented. Dead time between primary-side switch and secondary-side synchronous rectifiers can be independently programmed.

• Pre-biased Startup
• Synchronous Rectifier Control Outputs with Programmable Delays (Including Zero Delay Support)
• Voltage Mode Control with Input Voltage Feed-Forward or Current Mode Control
• Primary or Secondary-Side Control
• 3.3-V, 1.5% Accurate Reference Output
• 1-MHz Capable Switching Frequency
• 1% Accurate Cycle-by-Cycle Over Current Protection with Matched Duty Cycle Outputs
• Programmable Soft-Start and Hiccup Restart Timer
• Thermally Enhanced 4-mm x 4-mm QFN-20 Package and 20-pin TSSOP Package
• APPLICATIONS
  • Half-Bridge, Full-Bridge, Interleaved Forward, and Push-Pull Isolated Converters
  • Telecom and Data-com Power
  • Wireless Base Station Power
  • Server Power
  • Industrial Power Systems