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

8.2.1.2 Detailed Design Procedure

Current setting by a sense resistor is as described in Equation 1.

Equation 2. TPS92611-Q1 eq-app-Rsns1-slds238.gif

LED-string maximum forward voltage = 3 × 2.5 V = 7.5 V.

With 400-mV headroom reserved for the TPS92611-Q1 device between SUPPLY and OUT, the TPS92611-Q1 device must disable open-circuit detection when the supply voltage is below 7.9 V by using the DIAGEN feature.

Equation 3. TPS92611-Q1 eq04-Vildiag-SLDS238.gif

Set R1 = 10 kΩ, R2 = 65.6 kΩ.

Total device power consumption at worst case is with 16-V input and LEDs at minimal forward voltage.

Equation 4. TPS92611-Q1 eq06-Pmax_SLDS233.gif

TI recommends to add capacitors C1 and C2 at SUPPLY and OUT. TI recommends C1 of 1 µF and 100 nF close to the SUPPLY pin, and C2 of 10 nF close to the OUT pin. A larger capacitor for C1 or C2 is helpful for EMC and ESD; however, it takes a longer time to charge up the capacitor and could affect PWM dimming performance.