SLUSDX3C november   2020  – august 2023 UCC25800-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Device Comparison Table
  7. 6 Pin Configuration and Functions
  8. 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 Typical Characteristics
  9. 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 Oscillator
      3. 8.3.3 External Synchronization
      4. 8.3.4 Dead-Time
        1. 8.3.4.1 Adaptive Dead-time
        2. 8.3.4.2 Maximum Programmable Dead-time
      5. 8.3.5 Protections
        1. 8.3.5.1 Overcurrent Protection
          1. 8.3.5.1.1 OCP Threshold Setting
          2. 8.3.5.1.2 Output Power Capability
        2. 8.3.5.2 Input Overvoltage Protection (OVP)
        3. 8.3.5.3 Over-Temperature Protection (TSD)
        4. 8.3.5.4 Pin-Fault Protections
        5. 8.3.5.5 VREG Pin Protection
      6. 8.3.6 DIS/FLT Pin operation
        1. 8.3.6.1 FAULT Codes
    4. 8.4 Device Functional Modes
      1. 8.4.1 UVLO Mode
      2. 8.4.2 Soft-start Mode
      3. 8.4.3 Normal Operation Mode
      4. 8.4.4 Disabled Mode
      5. 8.4.5 Fault Modes
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 LLC Converter Operation Principle
      2. 9.2.2 Design Requirements
      3. 9.2.3 Detailed Design Procedure
      4. 9.2.4 Application Curves
    3. 9.3 What to Do and What Not to Do
  11. 10Power Supply Recommendations
  12. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  13. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Support Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  14. 13Mechanical, Packaging, and Orderable Information

Package Options

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

8.3.4.2 Maximum Programmable Dead-time

During operation, the voltage on the OC/DT pin sets a maximum duration of the dead-time. If the adaptive dead-time has not triggered the turn-on of the internal MOSFET within this time, it switches on when the maximum dead-time expires. The relationship between the OC/DT pin voltage and this maximum programmable dead-time is shown in Figure 8-9 and given by Equation 3. The UCC25800-Q1 transformer driver also limits the maximum dead-time to be 1/8 of the switching cycle. Therefore, the programmed maximum dead-time is the lower value of these two.

Equation 3. D T M A X = 150   n s   × 1   V V O C / C T - 0.9   V
GUID-E1A76F96-0510-40C3-8735-76C6F08CA35F-low.svg Figure 8-9 Maximum dead time vs. OC/DT pin voltage

When the OC/DT pin voltage falls below 0.5 V, the transformer driver triggers the pin-short protection and it shuts down. When the OC/DT pin voltage is between 0.5 V to 3.95 V, the maximum dead-time is set by Equation 3 with a clamped maximum value of 1.35 μs and a clamped minimum value of 50 ns. When the OC/DT pin voltage is between 3.95 V and 4.5 V, it triggers the DT-out-of-range fault and the transformer driver shuts down. When the OC/DT pin voltage is above 4.5 V, the transformer driver shuts down due to the OC/DT open pin fault protection.