SLVSF07 July   2021 TPS7H5001-SP

ADVANCE INFORMATION  

  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Pin Configuration and Functions
  6. Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  7. Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  VIN and VLDO
      2. 7.3.2  Startup
      3. 7.3.3  Enable and Undervoltage Lockout (UVLO)
      4. 7.3.4  Voltage Reference
      5. 7.3.5  Error Amplifier
      6. 7.3.6  Output Voltage Programming
      7. 7.3.7  Soft-Start (SS)
      8. 7.3.8  Switching Frequency and External Synchronization
        1. 7.3.8.1 Internal Oscillator Mode
        2. 7.3.8.2 External Synchronization Mode
        3. 7.3.8.3 Primary-Secondary Mode
      9. 7.3.9  Primary Switching Outputs (OUTA and OUTB)
      10. 7.3.10 Synchronous Rectifier Outputs (SRA and SRB)
      11. 7.3.11 Dead Time and Leading Edge Blank Time Programmability (PS, SP, and LEB)
      12. 7.3.12 Pulse Skipping
      13. 7.3.13 Duty Cycle Programmability
      14. 7.3.14 Current Sense and PWM Generation (CS_ILIM)
      15. 7.3.15 Hiccup Mode Operation (HICC)
      16. 7.3.16 External Fault Protection (FAULT)
      17. 7.3.17 Slope Compensation (RSC)
      18. 7.3.18 Frequency Compensation
      19. 7.3.19 Thermal Shutdown
    4. 7.4 Device Functional Modes
  8. Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1  Switching Frequency
        2. 8.2.2.2  Output Voltage Programming Resistors
        3. 8.2.2.3  Dead Time
        4. 8.2.2.4  Leading Edge Blank Time
        5. 8.2.2.5  Soft-Start Capacitor
        6. 8.2.2.6  Transformer
        7. 8.2.2.7  Main Switching FETs
        8. 8.2.2.8  Synchronous Rectificier FETs
        9. 8.2.2.9  RCD Clamp
        10. 8.2.2.10 Output Inductor
        11. 8.2.2.11 Output Capacitance and Filter
        12. 8.2.2.12 Sense Resistor
        13. 8.2.2.13 Hiccup Capacitor
        14. 8.2.2.14 Frequency Compensation Components
        15. 8.2.2.15 Slope Compensation Resistor
      3. 8.2.3 Application Curves
  9. Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
  • HFT|22
Thermal pad, mechanical data (Package|Pins)
Orderable Information

Pulse Skipping

In order to prevent converter operational issues related to the minimum on-time of the controller, specifically during high frequency operation, a pulse skipping mode has been implemented for the TPS7H5001-SP. During this mode, the primary outputs (OUTA and OUTB) will stop switching periodically. If the soft-start sequence of the converter has ended and the synchronous rectifier outputs are active, SRA and SRB will remain on during this period. If the device enters into pulse skipping during the soft-start sequence, SRA and SRB are not yet active and remain off. Having a minimum on-time that is too long in duration during high frequency operation can lead to an issue such as inductor current runaway during the soft-start period. Pulse skipping allows for overcoming this issue by reducing the peak inductor current during the startup period. In high frequency converter designs where the VIN to VOUT ratio of the converter may lead to required duty cycles that are less than the minimum on-time, the controller outputs will skip pulses in order to maintain the required output voltage. Pulse skipping will occur when both of the following conditions are present:

  • The voltage at the COMP pin is less than 0.3 V at the rising edge of the system clock
  • The previous duty cycle was less than 25%

When the duty cycle limit of the controller is set to 50% and both OUTA and OUTB are active, the number of pulses skipped by each of the primary outputs will be equal. This will ensure the volt-second balance is maintained across the transformer and that flux-walking that leads to transformer saturation is avoided in isolated topologies such as the push-pull.