SLVSCK5C September   2014  – January 2020 TPS92638-Q1

PRODUCTION DATA.  

  1. Features
  2. Applications
  3. Description
  4. Typical Application Schematic
  5. Revision History
  6. Pin Configuration and Functions
    1.     Pin Functions
  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 Switching Characteristics
    7. 7.7 Typical Characteristics
  8. Parameter Measurement Information
  9. Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 LED Current Setting
      2. 9.3.2 PWM Control
      3. 9.3.3 Fault Diagnostics
        1. 9.3.3.1 Open-Load Detection
      4. 9.3.4 Thermal Foldback
    4. 9.4 Device Functional Modes
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Applications
      1. 10.2.1 PWM Dimming by Bank
        1. 10.2.1.1 Design Requirements
        2. 10.2.1.2 Detailed Design Procedure
        3. 10.2.1.3 Application Performance Plots
      2. 10.2.2 Two Brightness Levels for TAIL and STOP Lights
        1. 10.2.2.1 Design Requirements
        2. 10.2.2.2 Detailed Design Procedure
      3. 10.2.3 PWM Dimming by Modulated Supply
        1. 10.2.3.1 Design Requirements
        2. 10.2.3.2 Design Procedure
      4. 10.2.4 Driving LEDs From a Single Device With Channels in Parallel
        1. 10.2.4.1 Design Requirements
        2. 10.2.4.2 Design Procedure
      5. 10.2.5 Driving LEDs From Multiple Devices With Channels in Parallel
        1. 10.2.5.1 Design Requirements
        2. 10.2.5.2 Design Procedure
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
    3. 12.3 Thermal Information
  13. 13Device and Documentation Support
    1. 13.1 Trademarks
    2. 13.2 Electrostatic Discharge Caution
    3. 13.3 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

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

Thermal Information

This device operates a thermal shutdown (TSD) circuit as a protection from overheating. For continuous normal operation, the junction temperature should not exceed the thermal-shutdown trip point. If the junction temperature exceeds the thermal-shutdown trip point, the output turns off. When the junction temperature falls below the thermal-shutdown trip point minus hysteresis, the output turns on again.

Calculate the power dissipated by the device according to the following formula:

Equation 15. TPS92638-Q1 Eq15-Pic_SLVSCK5.gif

where:

nk = Number of LEDs for x channel

V(LEDk)= Voltage drop across one LED for x channel

V(REF) = Reference voltage, typically 1.24 V

I(LEDk) = Average LED current for channel k

After determining the power dissipated by the device, calculate the junction temperature from the ambient temperature and the device thermal impedance.

Equation 16. TPS92638-Q1 Eq14-Tj_SLVSCK5.gif

where:

TA = Ambient temperature

RθJA = Junction-to-ambient thermal impedance

P(IC) = Dissipated power