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

8.3.8 Thermal Foldback

The TPS92365x family integrates thermal shutdown protection to prevent the device from overheating. In order to provide design margin of system thermal performance, the device enables a programmable thermal foldback function which automatically reduces the full-scale max output current, IMAX, at high junction temperature. When the device along with the LEDs are mounted on the same thermal substrate, the thermal performance is effectively improved due to the reduction of dissipation need for both device and LED.

As the device junction temperature rises above the thermal foldback threshold temperature, TTH, the full-scale max current starts to reduce following the current-temperature curve shown in the below figure. The current starts to reduce from the 100% level at typically rate of 2% of IMAX per °C until it drops to 50% of the full scale. Once the junction temperature rises 25°C above the TTH, the current continues to decrease at a lower rate until the temperature reaches above the overtemperature shutdown threshold temperature, TTSD.

GUID-FE5BD1AC-0CEE-426F-8EE4-A14142F74DFA-low.svg Figure 8-6 Thermal Foldback

The TTH can be adjusted by changing the resistor RTEMP connected between the TEMP and AGND pin. The TTH and the corresponding RTEMP value are listed in below table.

Table 8-4 TTH vs. RTEMP resistor value
TTH (°C) Resistor Value (kΩ)
80 200
90 100
100 60
110 40
120 28
130 20
140 15
150 10