SLUS769D July   2013  – December 2016 UCC28910 , UCC28911


  1. Features
  2. Applications
  3. Description
  4. Simplified Schematic
  5. Revision History
  6. Device Comparison Table
  7. Pin Configuration and Functions
  8. Detailed Pin Description
    1. 8.1 VDD (Device Voltage Supply)
    2. 8.2 GND (Ground)
    3. 8.3 VS (Voltage Sense)
    4. 8.4 IPK (Set the Maximum DRAIN Current Peak)
    5. 8.5 DRAIN
  9. Specifications
    1. 9.1 Absolute Maximum Ratings
    2. 9.2 Storage Conditions
    3. 9.3 ESD Ratings
    4. 9.4 Recommended Operating Conditions
    5. 9.5 Thermal Information
    6. 9.6 Electrical Characteristics
    7. 9.7 Switching Characteristics
    8. 9.8 Typical Characteristics
  10. 10Detailed Description
    1. 10.1 Overview
    2. 10.2 Functional Block Diagram
    3. 10.3 Feature Description
      1. 10.3.1 Primary-Side Voltage Regulation
      2. 10.3.2 Primary-Side Current Regulation
      3. 10.3.3 Voltage Feed Forward Compensation
      4. 10.3.4 Control Law
      5. 10.3.5 Valley Switching
      6. 10.3.6 Startup Operation
      7. 10.3.7 Fault Protection
        1. Output Over-Voltage
        2. Input Under-Voltage
        3. Primary Over-Current
        4. VDD Clamp Over-Current
        5. Thermal shutdown
      8. 10.3.8 EMI Dithering
    4. 10.4 Device Functional Modes
  11. 11Applications and Implementation
    1. 11.1 Application Information
    2. 11.2 Typical Application
      1. 11.2.1 Battery Charger, 5 V, 6 W
        1. Design Requirements
        2. Detailed Design Procedure
          1.  Power Handling Curves
          2.  Input Stage Design and Bulk Capacitance
          3.  Transformer Turns Ratio
          4.  Output Capacitance
          5.  VDD Capacitance, CVDD
          6.  VS Resistor Divider
          7.  RVDD Resistor and Turn Ratio
          8.  Transformer Input Power
          9.  RIPK Value
          10. Transformer Primary Inductance Value
            1. Secondary Diode Selection
          11. Pre-Load
          12. DRAIN Voltage Clamp Circuit
      2. 11.2.2 Application Curves
        1. Average Efficiency Performance and Standby Power of the UCC28910FBEVM-526
      3. 11.2.3 Multi-Output Converter with UCC2891x Devices
      4. 11.2.4 Do’s and Don'ts
  12. 12Power Supply Recommendations
  13. 13Layout
    1. 13.1 Layout Guidelines
    2. 13.2 Layout Example
  14. 14Device and Documentation Support
    1. 14.1 Documentation Support
      1. 14.1.1 Device Nomenclature
        1. Definition of Terms
      2. 14.1.2 Related Documents
    2. 14.2 Trademarks
    3. 14.3 Electrostatic Discharge Caution
    4. 14.4 Glossary
    5. 14.5 Related Links
  15. 15Mechanical, Packaging, and Orderable Information



Device and Documentation Support

Documentation Support

Device Nomenclature

Definition of Terms

Capacitance Terms in Farads

  • CBULK: total input capacitance of CB1 and CB2.
  • CVDD: capacitance on the VDD terminal.
  • COUT: output capacitance.

Duty Cycle Terms

Frequency Terms in Hertz

  • fLINE: minimum line frequency.
  • fTARGET(max): target full-load maximum switching frequency of the converter.
  • fMIN: minimum switching frequency of the converter, add 15% margin over the fSW(min) limit of the device.
  • fSW(min): minimum switching frequency (see Electrical Characteristics)

Current Terms in Amperes

  • IOCC: converter output current target when operating in constant current mode.
  • ID_PK(max): maximum transformer primary current peak.
  • ITRAN: required positive load-step current.
  • IRUN: maximum current consumption of the device (see Electrical Characteristics).
  • IVSLRUN: VS terminal run current (see Electrical Characteristics).

Current and Voltage Scaling Terms

Transformer Terms

  • LP: transformer primary inductance.
  • NPA: transformer primary-to-auxiliary turns ratio.
  • NPS: transformer primary-to-secondary turns ratio.

Power Terms in Watts

  • PIN: converter maximum input power.
  • PINTRX: transformer maximum input power.
  • POUT: full-load output power of the converter.
  • PSB: total stand-by input power.

Resistance Terms in Ω

  • RIPK: primary current programming resistance.
  • RESR: total ESR of the output capacitors.
  • RPRL: preload resistance on the output of the converter.
  • RS1: high-side VS terminal resistance.
  • RS2: low-side VS terminal resistance.

Timing Terms in Seconds

  • tDMAG(min): minimum secondary rectifier conduction time.
  • tON(min): minimum MOSFET on time.
  • tR: resonant frequency during the DCM (discontinuous conduction mode) time.

Voltage Terms in Volts

  • VBULK: highest bulk capacitor voltage for stand-by power measurement.
  • VBULK(min): minimum voltage on CB1 and CB2 at full power.
  • VCCR: constant-current regulating voltage (see Electrical Characteristics).
  • V: output voltage drop allowed during the load-step transient.
  • VDSPK: peak MOSFET drain-to-source voltage at high line.
  • VF: secondary rectifier, DOUT, forward voltage drop at near-zero current.
  • VFA: auxiliary rectifier, D2, forward voltage drop.
  • VOCV: regulated output voltage of the converter, VOUT in CV mode.
  • VVDD: voltage value on VDD terminal.
  • VOCC: target lowest converter output voltage in constant-current regulation.
  • VREV: peak reverse voltage on the secondary rectifier, DOUT.
  • VRIPPLE: output peak-to-peak ripple voltage at full-load.
  • VVSR: CV regulating level at the VS input (see Electrical Characteristics).
  • ΔVUVLO: VDDON – VDDOFF (see Electrical Characteristics).

AC Voltage Terms in VRMS

  • VIN(max): maximum AC input voltage to the converter.
  • VIN(min): minimum AC input voltage to the converter.
  • VIN(run): converter input start-up (run) AC voltage.

Efficiency Terms

  • η: converter overall efficiency.
  • ηXFMR: transformer primary-to-secondary power transfer efficiency.

Related Documents

Using the UCC28910 EVM-526, Evaluation Module, Texas Instruments Literature Number SLUUAI4


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Electrostatic Discharge Caution


These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates.


SLYZ022TI Glossary.

This glossary lists and explains terms, acronyms, and definitions.

Related Links

The table below lists quick access links. Categories include technical documents, support and community resources, tools and software, and quick access to sample or buy.

Table 5. Related Links

UCC28910, UCC28911 Click here Click here Click here Click here Click here