SLVSGH1A April   2023  – September 2023 TPS923652 , TPS923653 , TPS923654 , TPS923655

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Device Comparison Table
  7. 6 Pin Configuration and Functions
  8. 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 Typical Characteristics
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Adaptive Off-Time Current Mode Control
        1. 8.3.1.1 Switching Frequency Settings
        2. 8.3.1.2 Spread Spectrum
      2. 8.3.2 Setting LED Current
      3. 8.3.3 Undervoltage Lockout
      4. 8.3.4 Internal Soft Start
      5. 8.3.5 Dimming Mode
        1. 8.3.5.1 PWM Dimming
        2. 8.3.5.2 Analog Dimming
        3. 8.3.5.3 Hybrid Dimming
        4. 8.3.5.4 Flexible Dimming
      6. 8.3.6 CC/CV Charging Mode
      7. 8.3.7 Fault Protection
      8. 8.3.8 Thermal Foldback
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 TPS923654 Boost, 12-V Input, 1-A Output, 12-piece WLED Driver With Analog Dimming
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Inductor Selection
          2. 9.2.1.2.2 Input Capacitor Selection
          3. 9.2.1.2.3 Output Capacitor Selection
          4. 9.2.1.2.4 Sense Resistor Selection
          5. 9.2.1.2.5 Other External Components Selection
        3. 9.2.1.3 Application Curves
      2. 9.2.2 TPS923654 Buck-Boost, 24-V Input, 2-A Output, 4-piece WLED Driver with PWM Dimming
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
          1. 9.2.2.2.1 Inductor Selection
          2. 9.2.2.2.2 Input Capacitor Selection
          3. 9.2.2.2.3 Output Capacitor Selection
          4. 9.2.2.2.4 Sense Resistor Selection
          5. 9.2.2.2.5 Other External Components Selection
        3. 9.2.2.3 Application Curves
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Receiving Notification of Documentation Updates
    2. 10.2 Support Resources
    3. 10.3 Trademarks
    4. 10.4 Electrostatic Discharge Caution
    5. 10.5 Glossary
  12. 11Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information
9.2.2.2.2 Input Capacitor Selection

An input capacitor is required to reduce the surge current drawn from the input supply and the switching noise coming from the device. Electrolytic capacitors are recommended for energy storage. Ceramic capacitors with X5R or X7R dielectrics are highly recommended because of their low ESR and small temperature coefficients. For most applications, it is recommended to place a 10-μF capacitor along with a 0.1-µF capacitor from VIN to PGND/AGND to provide high-frequency filtering. The input capacitor voltage rating must be greater than the maximum input voltage. Use Equation 16 to calculate the input ripple voltage, where ESRCIN is the ESR of input capacitor, and KDR is the derating coefficient of ceramic capacitance at the applied DC voltage.

Equation 16. V I N ( r i p p l e ) = I L ( m a x ) × ( V O U T K D R × C I N × f S W × ( V I N ( m a x ) + V O U T ) + E S R C I N )

In this design, a 100-µF, 50V electrolytic capacitor, a 4.7-µF, 100V X7R ceramic capacitor and a 0.1-µF, 100V X7R ceramic capacitor are chosen, yielding around 190-mV input ripple voltage.