SNVSCV5 October   2025 TPS923621 , TPS923622

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
  7. 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
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Enable and Start-up
      2. 7.3.2 Under-Voltage Lockout (UVLO)
      3. 7.3.3 Shutdown
      4. 7.3.4 Boost Control Operation
      5. 7.3.5 Switching Peak Current Limit
      6. 7.3.6 Over-Voltage Protection
      7. 7.3.7 Output Current Setting
      8. 7.3.8 Output Current PWM Controlled Analog Dimming
      9. 7.3.9 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Normal Operation Mode
      2. 7.4.2 Over-Voltage Protection Mode
      3. 7.4.3 Shutdown Mode
  9. 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 Inductor Selection
        2. 8.2.2.2 Schottky Diode Selection
        3. 8.2.2.3 Output Capacitor Selection
        4. 8.2.2.4 LED Current Set Resistor
        5. 8.2.2.5 Thermal Considerations
      3. 8.2.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Device Support
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

7.3.1 Enable and Start-up

The ADIM pin performs not only the dimming function, but also the enable/shutdown function. When the VIN voltage is above the UVLO threshold, the TPS923621/2 can be enabled by driving the ADIM pin higher than the threshold voltage VADIM_H for a period longer than tADIM_EN.

Soft-start function is integrated into the device to avoid high inrush current spike during start-up. After the device is enabled, the GM amplifier output voltage ramps up very slowly. During this period, the switch current limit is set to ILIM_STRAT. After this period, the switch current limit changes back to ILIM and the FB pin voltage ramps up to reference voltage slowly. These features maintain the smooth start-up and minimize the inrush current.