SLVSCS1B March   2015  – May 2015 UCD7138


  1. Features
  2. Applications
  3. Description
  4. Simplified Schematic
  5. Revision History
  6. Pin Configuration and Functions
  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. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Body-Diode Conduction Detection
      2. 8.3.2 Gate Turnon and Turnoff
      3. 8.3.3 VCC and Undervoltage Lockout
      4. 8.3.4 Operating Supply Current
      5. 8.3.5 Driver Stage
    4. 8.4 Device Functional Modes
      1. 8.4.1 UVLO Mode
      2. 8.4.2 Normal Operation Mode
  9. Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Half-Bridge LLC
        1. Design Requirements
          1. Gate Input
          2. Gate Output
          3. Drain-to-Source Voltage Sensing
          4. DTC Output
          5. Turn-on Edge Optimization
        2. Detailed Design Procedure
          1. Design Without SR-Control Optimization
          2. Setting the DTC Detection Window
          3. Setting the Clamps
          4. Setting the DTC Optimization Target and Hysteresis
          5. Setting the DTC Negative Current Fault Protection
        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 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Community Resource
    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

  • Low-Side Gate Driver With Body-Diode Conduction Sensing
  • Gate Turnoff Edge Body-Diode Conduction Reporting
  • Gate Turnon Edge Delay Optimization
  • Works Together With the Dead-Time Compensation (DTC) Module in the UCD3138A Family of Digital Power Controllers:
    • Automatic or Manual Dead-Time Adjustment of Gate Turnon and Turnoff Edges
    • Negative Current Protection
  • -150-mV Body-Diode Conduction Sensing Threshold
  • Able to Sense Body Diode Conduction Times as Low as 10 ns
  • 4-A Peak-Source and 6-A Peak-Sink Drive Current
  • Fast Propagation Delays (14-ns Typical)
  • Fast Rise and Fall Times (5-ns Typical)
  • Up to 2-MHz Operating Frequency
  • 4.5-V to 18-V Supply Range
  • Rail-to-Rail Drive Capability
  • VCC Undervoltage Lockout (UVLO)
  • 6-Pin 3-mm × 3-mm WSON-6 Package

2 Applications

  • LLC Converters
  • Hard Switching Full-Bridge Converters
  • Digital Power-Control Applications

3 Description

The UCD7138 device is a 4-A and 6-A single-channel MOSFET driver with body-diode conduction sensing and reporting and is a high performance driver that allows the Texas Instruments UCD3138A digital PWM controller to achieve advanced synchronous-rectification (SR) control. The device contains a high-speed gate driver, a body-diode conduction-sensing circuit, and a turnon delay optimization circuit. The device is suitable for high-power, high-efficiency isolated converter applications where SR dead-time optimization is desired.

The UCD7138 device offers asymmetrical rail-to-rail 4-A source and 6-A sink peak-current drive capability. The short propagation delay and fast rise and fall time allows efficient operation at high frequencies. An internal high-speed comparator with a –150-mV threshold detects the body-diode conduction and reports the information to the UCD3138A digital-power controller. The UCD7138 device is capable of sensing body-diode conduction time as low as 10 ns. The SR turnon edge is optimized by the UCD7138 device. The SR turnoff edge is optimized by the UCD3138A digital-power controller which analyzes the body-diode conduction information reported by the UCD7138 DTC pin.

The benefits of the chipset include maximizing system efficiency by minimizing body-diode conduction time, robust and fast negative-current protection, and a simple interface.

Device Information(1)

UCD7138 WSON (6) 3.00 mm × 3.00 mm
  1. For all available packages, see the orderable addendum at the end of the datasheet.

4 Simplified Schematic

UCD7138 alt_slvscs1.gif

Power Savings for a 340-W LLC Application

UCD7138 D001_slvscs1.gif