SLUS710E May   2006  – January 2024 TPS28225

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Switching Characteristics
    7. 5.7 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Undervoltage Lockout (UVLO)
      2. 6.3.2 Output Active Low
      3. 6.3.3 Enable/Power Good
      4. 6.3.4 3-State Input
        1. 6.3.4.1 TPS28225 3-State Exit Mode
        2. 6.3.4.2 External Resistor Interference
      5. 6.3.5 Bootstrap Diode
      6. 6.3.6 Upper and Lower Gate Drivers
      7. 6.3.7 Dead-Time Control
      8. 6.3.8 Thermal Shutdown
    4. 6.4 Device Functional Modes
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1 Four Phases Driven by TPS28225 Driver
        2. 7.2.2.2 Switching The MOSFETs
        3. 7.2.2.3 List of Materials
      3. 7.2.3 Application Curves
    3. 7.3 System Examples
  9. 8 Power Supply Recommendations
  10. 9 Layout
    1. 9.1 Layout Guidelines
    2. 9.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Device Support
      1. 10.1.1 Third-Party Products Disclaimer
    2. 10.2 Documentation Support
      1. 10.2.1 Related Documentation
    3. 10.3 Receiving Notification of Documentation Updates
    4. 10.4 Support Resources
    5. 10.5 Trademarks
    6. 10.6 Electrostatic Discharge Caution
    7. 10.7 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information

Package Options

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

7.2.2.1 Four Phases Driven by TPS28225 Driver

When using the same power stage Figure 7-1, the driver with the optimal drive voltage and optimal dead time can boost efficiency up to 5%. The optimal 8-V drive voltage versus 5-V drive contributes 2% to 3% efficiency increase and the remaining 1% to 2% can be attributed to the reduced dead time. The 7-V to 8-V drive voltage is optimal for operation at switching frequency range above 400 kHz and can be illustrated by observing typical RDS(on) curves of modern FETs as a function of their gate-drive voltage. This is shown in Figure 7-2.

Figure 7-2 and Figure 7-3 show that the RDS(on) at 5-V drive is substantially larger than at 7 V and above that the RDS(on) curve is almost flat. This means that moving from 5-V drive to an 8-V drive boosts the efficiency because of lower RDS(on) of the MOSFETs at 8 V. Further increase of drive voltage from 8 V to 12 V only slightly decreases the conduction losses but the power dissipated inside the driver increases dramatically (by 125%). The power dissipated by the driver with 5-V, 8-V and 12-V drive as a function of switching frequency from 400 kHz to 800 kHz. It should be noted that the 12-V driver exceeds the maximum dissipated power allowed for an SOIC-8 package even at 400-kHz switching frequency.

GUID-17D41D4F-3966-4DDD-ABCF-E7AB07CBE1BF-low.gif
Figure 7-2 RDS(on) of MOSFET as Function of VGS
GUID-72C0E7FF-00B9-4A73-8D1F-7906FD922B81-low.gif
Figure 7-3 Drive Power as Function of VGS and FSW