SLDS238B January   2018  – January  2020 TPS92611-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Typical Application Diagram
  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 Timing Requirements
    7. 6.7 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Device Bias
        1. 7.3.1.1 Power-On Reset (POR)
        2. 7.3.1.2 Low-Quiescent-Current Fault Mode
      2. 7.3.2 Constant-Current Driver
      3. 7.3.3 Device Enable
      4. 7.3.4 PWM Dimming
      5. 7.3.5 Diagnostics
        1. 7.3.5.1 DIAGEN
        2. 7.3.5.2 Low-Dropout Mode
        3. 7.3.5.3 Open-Circuit Detection
        4. 7.3.5.4 Short-to-GND Detection
        5. 7.3.5.5 Overtemperature Protection
      6. 7.3.6 Fault-Bus Output With One-Fails–All-Fail
    4. 7.4 Device Functional Modes
      1. 7.4.1 Undervoltage Lockout, V(SUPPLY) < V(POR_rising)
      2. 7.4.2 Normal Operation V(SUPPLY) ≥ 4.5 V
      3. 7.4.3 Low-Voltage Dropout
      4. 7.4.4 Fault Mode
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Single-Channel LED Driver With Diagnostics
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curve
      2. 8.2.2 Single-Channel LED Driver With Heat Sharing
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 Application Curve
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    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

Package Options

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

8.2.2 Single-Channel LED Driver With Heat Sharing

Using parallel resistors, thermal performance can be improved by balancing current between the TPS92611-Q1 device and the external resistors as follows. As the current-sense resistor controls the total LED string current, the LED string current I(LED) is set by V(CS_REG) / R(SNS), while the TPS92611-Q1 current I(DRIVE) and parallel resistor current I(P) combine to the total current. Note that the device is not able to control the parallel resistor path, thus TI does not suggest to use one-fails–all-fail with this topology. For PWM applications, TI suggests to add an external bipolar switch at the bottom of LED strings. The PWM input and bipolar switch inputs must be tied together to minimize delay mismatch and to avoid false open-circuit faults.

TPS92611-Q1 app-parallel-resistor-schematic-SLDS238.gifFigure 21. Heat Sharing With a Parallel Resistor