SLVSFS4A December   2021  – June 2022 TPS92623-Q1

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and 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 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  Power Supply (SUPPLY)
        1. 7.3.1.1 Power-On Reset (POR)
        2. 7.3.1.2 Suppply Current in Fault Mode
      2. 7.3.2  Enable and Shutdown
      3. 7.3.3  Constant-Current Output and Setting (INx)
      4. 7.3.4  Thermal Sharing Resistor (OUTx and RESx)
      5. 7.3.5  PWM Control (PWMx)
      6. 7.3.6  Supply Control
      7. 7.3.7  Diagnostics
        1. 7.3.7.1 LED Short-to-GND Detection
        2. 7.3.7.2 LED Open-Circuit Detection
        3. 7.3.7.3 LED Open-Circuit Detection Enable (DIAGEN)
        4. 7.3.7.4 Overtemperature Protection
        5. 7.3.7.5 Low Dropout Operation
      8. 7.3.8  FAULT Bus Output with One-Fails-All-Fail
      9. 7.3.9  FAULT Table
      10. 7.3.10 LED Fault Summary
      11. 7.3.11 IO Pins Inner Connection
    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 Operation
      4. 7.4.4 Fault Mode
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 BCM Controlled Rear Lamp With One-Fails-All-Fail Setup
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curves
      2. 8.2.2 Independent PWM Controlled Rear Lamp By MCU
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 Application Curves
  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 Receiving Notification of Documentation Updates
    2. 11.2 Support Resources
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

7.3.7.2 LED Open-Circuit Detection

The TPS92623-Q1 device has LED open-circuit detection. The LED open-circuit detection monitors the output voltage when the current output is enabled. The LED open-circuit detection is only enabled when DIAGEN is HIGH. A short-to-battery fault is also detected and recognized as an LED open-circuit fault.

The TPS92623-Q1 monitors dropout-voltage differences between the IN and OUT pins for each LED channel when PWM is HIGH. The voltage difference V(INx) – V(OUTx) is compared with the internal reference voltage V(OPEN_th_rising) to detect an LED open-circuit incident. If V(OUTx) rises and causes V(INx) – V(OUTx) less than the V(OPEN_th_rising) voltage longer than the deglitch time of t(OPEN_deg), the device asserts an open-circuit fault. After a LED open-circuit failure is detected, the internal constant-current sink pulls down the FAULT pin voltage. During the deglitch time period, if V(OUTx) falls and makes V(INx) – V(OUTx) larger than V(OPEN_th_falling), the deglitch timer is reset.

The TPS92623-Q1 shuts down the output current regulation for the error channel after LED open-circuit fault is detected. The device sources a small current I(Retry) from SUPPLY to OUT and RES when DIAGEN input is logic High. After the fault condition is removed, the device resumes normal operation and releases the FAULT pin. Figure 7-4 illustrates the timing for LED open-circuit detection, protection, retry and recovery.

Figure 7-4 LED Open-Circuit Detection and Recovery Timing Diagram

The detailed information and value of each time period in Figure 7-4 is described in Electrical Characteristics.