SLVSE06B January   2018  – JANUARY 2019 TPSM846C24

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
      2.      Efficiency vs Output Current
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 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 Switching Characteristics
    7. 6.7 Typical Characteristics (VIN = 12 V)
    8. 6.8 Typical Characteristics (VIN = 5 V)
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Minimum Capacitance Requirements
      2. 7.3.2  Setting the Compensation Network
      3. 7.3.3  Transient Response
      4. 7.3.4  Setting the Output Voltage
      5. 7.3.5  Differential Remote Sense
      6. 7.3.6  Switching Frequency and Synchronization
        1. 7.3.6.1 Setting the Switching Frequency
        2. 7.3.6.2 Synchronization
          1. 7.3.6.2.1 Stand-Alone Device Synchronization
          2. 7.3.6.2.2 Paralleled Devices Synchronization
      7. 7.3.7  Prebiased Output Start-Up
      8. 7.3.8  Power-Good (PGOOD) Indicator
      9. 7.3.9  Linear Regulators BP3 and BP6
      10. 7.3.10 Parallel Application
      11. 7.3.11 Parallel Operation
      12. 7.3.12 Overtemperature Protection
      13. 7.3.13 Overcurrent Protection
      14. 7.3.14 Output Overvoltage and Undervoltage Protection
    4. 7.4 Device Functional Modes
      1. 7.4.1 Active Mode
      2. 7.4.2 Shutdown Mode
  8. 8 Application and Implementation
    1. 8.1 Typical Application
      1. 8.1.1 Design Requirements
      2. 8.1.2 Detailed Design Procedure
        1. 8.1.2.1 Custom Design With WEBENCH® Tools
        2. 8.1.2.2 Setting the Output Voltage
        3. 8.1.2.3 Input and Output Capacitance
        4. 8.1.2.4 Selecting the Compensation Components
        5. 8.1.2.5 Setting the Switching Frequency
        6. 8.1.2.6 Power Good (PGOOD)
        7. 8.1.2.7 ON/OFF Control (EN)
      3. 8.1.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 Package Specifications
    4. 10.4 EMI
    5. 10.5 Mounting and Thermal Profile Recommendation
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Support
        1. 11.1.1.1 Custom Design With WEBENCH® Tools
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information
    1. 12.1 Tape and Reel Information

Package Options

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

7.3.7 Prebiased Output Start-Up

The TPSM846C24 devices prevent current from being discharged from the output during start-up when a prebiased output condition exists. If the output is prebiased, no PH pulses occur until the internal soft-start voltage rises above the error-amplifier input voltage (FB pin). As soon as the soft-start voltage exceeds the error-amplifier input, and PH pulses start. The device limits synchronous rectification after each PH pulse with a narrow on-time. The on-time of the low-side MOSFET slowly increases on a cycle-by-cycle basis until 128 pulses have been generated and the synchronous rectifier runs fully complementary to the high-side MOSFET. This approach prevents the sinking of current from a prebiased output, and ensures the output-voltage start-up and ramp-to-regulation sequences are smooth and monotonic.

If the prebias voltage is close to or exceeds the VOUT setpoint voltage, the mandatory 128 switching cycles, as previously described , may induce a non-monotonic dip in the output voltage. The output voltage quickly recovers to the setpoint value once the 128 cycle interval is completed.

These devices respond to a prebiased output overvoltage condition immediately upon VIN powered up and when the BP6 regulator voltage is above the BP6 UVLO of 3.73 V (typical).