SLUSD48C July   2018  – March 2022 UCC24624

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Description, Continued
  6. 6 Pin Configuration and Functions
    1.     Pin 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 Timing Requirements
    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 Power Management
      2. 8.3.2 Synchronous Rectifier Control
      3. 8.3.3 Turn-off Threshold Adjustment
      4. 8.3.4 Noise Immunity
        1. 8.3.4.1 On-Time Blanking
        2. 8.3.4.2 Off-Time Blanking
        3. 8.3.4.3 Two-Channel Interlock
        4. 8.3.4.4 SR Turn-on Re-arm
        5. 8.3.4.5 Adaptive Turn-on Delay
      5. 8.3.5 Gate Voltage Clamping
      6. 8.3.6 Standby Mode
    4. 8.4 Device Functional Modes
      1. 8.4.1 UVLO Mode
      2. 8.4.2 Standby Mode
      3. 8.4.3 Run Mode
  9. 9 Application 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 MOSFET Selection
        2. 9.2.2.2 Snubber Design
      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 Development Support
        1. 12.1.1.1 Custom Design With WEBENCH® Tools
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Community Resources
    4. 12.4 Trademarks

3 Description

The UCC24624 high-performance synchronous rectifier (SR) controller is dedicated for LLC resonant converters to replace the lossy diode output rectifiers with SR MOSFETs and improve the overall system efficiency.

The UCC24624 SR controller uses drain-to-source voltage sensing method to achieve on and off control of the SR MOSFET. Proportional gate drive is implemented to extend the SR conduction time, minimize the body diode conduction time. To compensate for the offset voltage caused by the SR MOSFET parasitic inductance, the UCC24624 implements an adjustable positive turn-off threshold to accommodate different SR MOSFET packages. UCC24624 has a built-in 475-ns on-time blanking and a fixed 650-ns off-time blanking to avoid SR false turn-on and turn-off. UCC24624 also integrates a two-channel interlock function that prevents the two SRs from being on at the same time. With 230-V voltage-sensing pins and 28-V ABS maximum VDD rating, it can be directly used in converters with output voltage up to 24.75 V. The internal clamp allows the controller to support 36-V output voltage easily by adding an external current limiting resistor on VDD.

Device Information
PART NUMBERPACKAGEBODY SIZE (NOM)
UCC24624SOIC (8)4.90 mm × 3.91 mm

GUID-29294042-6F4C-4177-80E2-36F73F1FA1DE-low.gif Typical Application Schematic