SLUSCU6B August 2017  – August 2017 UCC256301


  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Pin Configuration and Functions
  6. Specifications
    1. 6.1Absolute Maximum Ratings
    2. 6.2ESD Ratings
    3. 6.3Recommended Operating Conditions
    4. 6.4Thermal Information
    5. 6.5Electrical Characteristics
    6. 6.6Switching Characteristics
    7. 6.7Typical Characteristics
  7. Detailed Description
    1. 7.1Overview
    2. 7.2Functional Block Diagram
    3. 7.3Feature Description
      1. 7.3.1 Hybrid Hysteretic Control
      2. 7.3.2 Regulated 12-V Supply
      3. 7.3.3 Feedback Chain
      4. 7.3.4 Optocoupler Feedback Signal Input and Bias
      5. 7.3.5 System External Shut Down
      6. 7.3.6 Pick Lower Block and Soft Start Multiplexer
      7. 7.3.7 Pick Higher Block and Burst Mode Multiplexer
      8. 7.3.8 VCR Comparators
      9. 7.3.9 Resonant Capacitor Voltage Sensing
      10. 7.3.10Resonant Current Sensing
      11. 7.3.11Bulk Voltage Sensing
      12. 7.3.12Output Voltage Sensing
      13. 7.3.13High Voltage Gate Driver
      14. 7.3.14Protections
        1. Region Prevention
        2. Current Protection (OCP)
        3. Output Voltage Protection (VOUTOVP)
        4. Input Voltage Protection (VINOVP)
        5. Input Voltage Protection (VINUVP)
        6. UVLO
        7. UVLO
        8. Temperature Protection (OTP)
    4. 7.4Device Functional Modes
      1. 7.4.1Burst Mode Control
      2. 7.4.2High Voltage Start-Up
      3. 7.4.3X-Capacitor Discharge
      4. 7.4.4Soft-Start and Burst-Mode Threshold
      5. 7.4.5System States and Faults State Machine
      6. 7.4.6Waveform Generator State Machine
  8. Application and Implementation
    1. 8.1Application Information
    2. 8.2Typical Application
      1. 8.2.1Design Requirements
      2. 8.2.2Detailed Design Procedure
        1. LLC Power Stage Requirements
        2. LLC Gain Range
        3. Select Ln and Qe
        4. Determine Equivalent Load Resistance
        5. Determine Component Parameters for LLC Resonant Circuit
        6. LLC Primary-Side Currents
        7. LLC Secondary-Side Currents
        8. LLC Transformer
        9. LLC Resonant Inductor
        10. Resonant Capacitor
        11. Primary-Side MOSFETs
        12. Considerations for Adaptive Dead-Time
        13. Rectifier Diodes
        14. Output Capacitors
        15. Pin Series Resistors
        16. Pin Voltage Divider
        17. Pin Voltage Divider
        18. Pin Differentiator
        19. Pin Capacitor Divider
        20. Mode Programming
        21. Capacitor
      3. 8.2.3Application Curves
  9. Power Supply Recommendations
    1. 9.1VCC Pin Capacitor
    2. 9.2Boot Capacitor
    3. 9.3RVCC Pin Capacitor
  10. 10Layout
    1. 10.1Layout Guidelines
    2. 10.2Layout Example
  11. 11Device and Documentation Support
    1. 11.1Device Support
      1. 11.1.1Development Support
        1. Design With WEBENCH® Tools
    2. 11.2Documentation Support (if applicable)
      1. 11.2.1Related Documentation
    3. 11.3Receiving Notification of Documentation Updates
    4. 11.4Community Resources
    5. 11.5Trademarks
    6. 11.6Electrostatic Discharge Caution
    7. 11.7Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
  • DDB|14
Orderable Information


  • Hybrid Hysteretic Control (HHC)
    • Best-in-Class Transient Response
    • Easy Compensation Design
  • Optimized Low Power Features Enable 75 mW
    Standby Power Design with PFC on
    • Advanced Burst Mode
      Opto-Coupler Low Power Operation
    • Helps Enable Compliance to CoC Tier II Standard
  • Fast Exit from Burst Mode
  • Improved Capacitive Region Avoidance Scheme
  • Adaptive Dead-Time
  • Internal High-Side Gate Drivers
    (0.6-A and 1.2-A Capability)
  • Robust Soft Start with No Hard Switching
  • Over Temperature, Output Over Voltage, Input
    Over and Under Voltage Protection with
    Three Levels of Over Current Protections
  • Wide Operating Frequency Range
    (35 kHz to 1 MHz)
  • LLC Resonant Controller in SOIC16
    with High Voltage Clearance
  • Create a Custom Design Using the UCC256301 With the WEBENCH® Power Designer


  • Digital TV SMPS
  • AC-DC Adapter
  • Power Tools
  • LED Lighting Applications


The UCC256301 is a fully featured LLC controller with integrated high-voltage gate driver. It has been designed to pair with a PFC stage to provide a complete power system using a minimum of external components. The resulting power system is designed to meet the most stringent requirements for standby power without the need for a separate standby power converter, and with PFC stage running all the time. UCC256301 includes a range of features designed to make LLC converter operation well controlled and robust. This device aims to unburden the LLC designer and allow mainstream applications to benefit from efficiency advantages of the LLC topology.

UCC256301 uses hybrid hysteretic control to provide best in class line and load transient response. The control effort is approximately linear proportional to average input current in one cycle. The control makes the open loop transfer function a first order system so that it’s very easy to compensate. The system is always stable with proper frequency compensation.

UCC256301 provides a high efficient burst mode with consistent burst power level during each burst on cycle. The burst power level is programmable and adaptively changes with input voltage, making the optimization of efficiency very easy.

Device Information(1)

UCC256301SOIC (16)9.9 mm x 3.9 mm
  1. For all available packages, see the orderable addendum at the end of the data sheet.

Simplified Schematic

UCC256301 alt_sluscu6.gif

Revision History

Changes from A Revision (August 2017) to B Revision

  • Changed Feature Bullet "Meets CoC Tier II Standard" to "Helps Enable Compliance to CoC Tier II Standard".Go
  • Deleted Integrated X-Capacitor Discharge Bullet.Go
  • Deleted Meets IEC60950 and IEC60065 Standards Bullet.Go
  • Deleted Meet UL60950-1 BulletGo
  • Changed Junction temperature range MAX value from 150°C to 125°C. Go
  • Changed HIGH VOLTAGE STARTUP, AC zero crossing detection window length for final test current stage values from MIN 46.704, TYP 48.313 and MAX 50.096 to MIN 43 ms, TYP 46 ms, and MAX 52 ms.Go
  • Changed BULK VOLTAGE SENSE, Input voltage that allows LLC to start switching MIN value from 2.99 ms to 2.969 ms.Go

Changes from * Revision (August 2017) to A Revision

  • Deleted the word safe and safety in three locations. Go