SLUS515G September   2002  – December 2015

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 UVLO and Reference Block
      2. 7.3.2 Error Amplifier
      3. 7.3.3 Zero Current Detection and Re-Start Timer Blocks
      4. 7.3.4 Enable Block
      5. 7.3.5 Zero Power Block
      6. 7.3.6 Multiplier Block
      7. 7.3.7 Overvoltage Protection (OVP) Block
    4. 7.4 Device Functional Modes
      1. 7.4.1 Transition Mode Control
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Inductor Selection
        2. 8.2.2.2 MOSFET Selection
        3. 8.2.2.3 Diode Selection
        4. 8.2.2.4 Capacitor Selection
        5. 8.2.2.5 Multiplier Set-Up
        6. 8.2.2.6 Sense Resistor Selection
        7. 8.2.2.7 Output Voltage Sense Design
        8. 8.2.2.8 Voltage Loop Design
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Bias Current
      2. 10.1.2 Zero Current Detection
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Support
    2. 11.2 Related Links
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

9 Power Supply Recommendations

The supply voltage for the device comes from VCC pin. This pin must be bypassed with a high-frequency capacitor (greater than 0.1 μF) and tied to GND. The UCC38050 has a wide UVLO hysteresis of approximately 6.3 V that allows use of a lower value supply capacitor on this pin for quicker and easier start-up. The UCC38051 has a narrow UVLO hysteresis with of about 2.8 V, and a start-up voltage of about 12.5 V for applications where the operation of the PFC device must be controlled by a downstream PWM controller.