SLUSB41A July   2012  – December 2014 UCC28700 , UCC28701 , UCC28702 , UCC28703

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Switching Characteristics
    7. 7.7 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Detailed Pin Description
        1. 8.3.1.1 VDD (Device Bias Voltage Supply)
        2. 8.3.1.2 GND (Ground)
        3. 8.3.1.3 VS (Voltage-Sense)
        4. 8.3.1.4 DRV (Gate Drive)
        5. 8.3.1.5 CS (Current Sense)
        6. 8.3.1.6 CBC (Cable Compensation), Pin 1 UCC28700
        7. 8.3.1.7 NTC (NTC Thermistor Shut-down), Pin 1 UCC28701/2/3
      2. 8.3.2 Fault Protection
    4. 8.4 Device Functional Modes
      1. 8.4.1 Primary-Side Voltage Regulation
      2. 8.4.2 Primary-Side Current Regulation
      3. 8.4.3 Valley-Switching
      4. 8.4.4 Start-Up Operation
  9. 9 Applications and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Transformer Parameter Verification
        2. 9.2.2.2 Output Capacitance
        3. 9.2.2.3 VDD Capacitance, CDD
        4. 9.2.2.4 VDD Start-Up Resistance, RSTR
        5. 9.2.2.5 VS Resistor Divider, Line Compensation, and Cable Compensation
        6. 9.2.2.6 Input Bulk Capacitance and Minimum Bulk Voltage
        7. 9.2.2.7 Transformer Turns Ratio, Inductance, Primary-Peak Current
        8. 9.2.2.8 Standby Power Estimate
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Device Nomenclature
        1. 12.1.1.1  Capacitance Terms in Farads
        2. 12.1.1.2  Duty Cycle Terms
        3. 12.1.1.3  Frequency Terms in Hertz
        4. 12.1.1.4  Current Terms in Amperes
        5. 12.1.1.5  Current and Voltage Scaling Terms
        6. 12.1.1.6  Transformer Terms
        7. 12.1.1.7  Power Terms in Watts
        8. 12.1.1.8  Resistance Terms in Ω
        9. 12.1.1.9  Timing Terms in Seconds
        10. 12.1.1.10 Voltage Terms in Volts
        11. 12.1.1.11 AC Voltage Terms in VRMS
        12. 12.1.1.12 Efficiency Terms
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
      2. 12.2.2 Related Links
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

1 Features

  • < 30-mW No-Load Power for 5-Star Rating
  • Primary-Side Regulation (PSR) Eliminates Opto-Coupler
  • ±5% Voltage and Current Regulation
  • 130-kHz Maximum Switching Frequency Enables High-Power Density Charger Designs
  • Quasi-Resonant Valley-Switching Operation for Highest Overall Efficiency
  • Patent-Pending Frequency-Jitter Scheme to Ease EMI Compliance
  • Wide VDD Range Allows Small Bias Capacitor
  • Clamped Gate-Drive Output for MOSFET
  • Protection Functions: Overvoltage, Low-Line, and Overcurrent
  • Programmable Cable Compensation (UCC28700 Only)
  • NTC Resistor Interface (UCC28701, UCC28702 and UCC28703 Only) With Fixed Cable Compensation Options
  • SOT-23 Package

2 Applications

  • USB-Compliant Adapters and Chargers for Consumer Electronics (Cell Phones, Tablets and Cameras)
  • AC and DC Power Supplies

3 Description

The UCC28700 family of flyback power supply controllers provides Constant-Voltage (CV) and Constant-Current (CC) output regulation without the use of an optical coupler. The devices process information from the primary power switch and an auxiliary flyback winding for precise control of output voltage and current. Low start-up current, dynamically controlled operating states and a tailored modulation profile support very low standby power without sacrificing start-up time or output transient response.

Control algorithms in the UCC28700 family allow operating efficiencies to meet or exceed applicable standards. The output drive interfaces to a MOSFET power switch. Discontinuous Conduction Mode (DCM) with valley switching reduces switching losses. Modulation of switching frequency and primary current peak amplitude (FM and AM) keeps the conversion efficiency high across the entire load and line ranges.

The controllers have a maximum switching frequency of 130 kHz and always maintain control of the peak-primary current in the transformer. Protection features help keep primary and secondary component stresses in check. The UCC28700 allows the level of cable compensation to be programmed. The UCC28701, UCC28702, and UCC28703 devices allow remote temperature sensing using a Negative Temperature Coefficient (NTC) resistor while providing fixed cable-compensation levels.

Device Information(1)

PART NUMBER PACKAGE BODY SIZE (NOM)
UCC28700 SOT-23 (6) 2.90 mm × 1.60 mm
UCC28701
UCC28702
UCC28703
  1. For all available packages, see the orderable addendum at the end of the datasheet.

Typical Application Schematic

app1_slusb41.gif