SLUSCR9B June   2017  – December 2020 UCC28730-Q1

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin 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 Timing Requirements
    7. 6.7 Switching Characteristics
    8. 6.8 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 Detailed Pin Description
        1. 7.3.1.1 VDD (Device Bias Voltage Supply)
        2. 7.3.1.2 GND (Ground)
        3. 7.3.1.3 HV (High Voltage Startup)
        4. 7.3.1.4 DRV (Gate Drive)
        5. 7.3.1.5 CBC (Cable Compensation)
        6. 7.3.1.6 VS (Voltage Sense)
        7. 7.3.1.7 CS (Current Sense)
      2. 7.3.2 Primary-Side Regulation (PSR)
      3. 7.3.3 Primary-Side Constant Voltage Regulation
      4. 7.3.4 Primary-Side Constant Current Regulation
      5. 7.3.5 Wake-Up Detection and Function
      6. 7.3.6 Valley-Switching and Valley-Skipping
      7. 7.3.7 Startup Operation
      8. 7.3.8 Fault Protection
    4. 7.4 Device Functional Modes
  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 Stand-By Power Estimate
        2. 8.2.2.2 Input Bulk Capacitance and Minimum Bulk Voltage
        3. 8.2.2.3 Transformer Turns Ratio, Inductance, Primary-Peak Current
        4. 8.2.2.4 Transformer Parameter Verification
        5. 8.2.2.5 Output Capacitance
        6. 8.2.2.6 VDD Capacitance, CVDD
        7. 8.2.2.7 VS Resistor Divider, Line Compensation, and Cable Compensation
        8. 8.2.2.8 VS Wake-Up Detection
      3. 8.2.3 Application Curves
    3. 8.3 Do's and Don'ts
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Device Nomenclature
        1. 11.1.1.1  Capacitance Terms in Farads
        2. 11.1.1.2  Duty-Cycle Terms
        3. 11.1.1.3  Frequency Terms in Hertz
        4. 11.1.1.4  Current Terms in Amperes
        5. 11.1.1.5  Current and Voltage Scaling Terms
        6. 11.1.1.6  Transformer Terms
        7. 11.1.1.7  Power Terms in Watts
        8. 11.1.1.8  Resistance Terms in Ω
        9. 11.1.1.9  Timing Terms in Seconds
        10. 11.1.1.10 DC Voltage Terms in Volts
        11. 11.1.1.11 AC Voltage Terms in Volts
        12. 11.1.1.12 Efficiency Terms
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Support Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.3.1.1 VDD (Device Bias Voltage Supply)

The VDD pin connects to a by-pass capacitor to ground. The turn-on UVLO threshold is 21 V and turn-off UVLO threshold is 7.7 V with an available operating range up to 35 V on VDD. The typical USB charging specification requires the output current to operate in Constant-Current mode from 5 V down to at least 2 V, which is easily achieved with a nominal VVDD of approximately 20 V. The additional VDD headroom up to 35 V allows for VVDD to rise due to the leakage energy delivered to the VDD capacitor during high-load conditions.