JAJSNQ5 may   2023 TPS92629-Q1

PRODUCTION DATA  

  1.   1
  2. 1 特長
  3. 2 アプリケーション
  4. 3 説明
  5. 4 Revision History
  6. 5 Pin Configuration and Functions
  7. 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
  8. 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 Supply Current in Fault Mode
      2. 7.3.2  Enable and Shutdown
      3. 7.3.3  Constant-Current Output and Setting (IN)
      4. 7.3.4  Thermal Sharing Resistor (OUT and RES)
      5. 7.3.5  Brightness Control (EN/PWM and ADIM)
      6. 7.3.6  Diagnostics
        1. 7.3.6.1 LED Short-to-GND Detection
        2. 7.3.6.2 LED Open-Circuit and Short-to-Battery Detection
        3. 7.3.6.3 LED Open-Circuit and Short-to-Battery Detection Enable (DIAGEN)
        4. 7.3.6.4 Overtemperature Protection
        5. 7.3.6.5 Low Dropout Operation
      7. 7.3.7  Multi Fault Report
      8. 7.3.8  FAULT Table
      9. 7.3.9  LED Fault Summary
      10. 7.3.10 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
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Using Analog Dimming Controlled By MCU for Blind Spot Detection
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 ドキュメントの更新通知を受け取る方法
    2. 9.2 サポート・リソース
    3. 9.3 Trademarks
    4. 9.4 静電気放電に関する注意事項
    5. 9.5 用語集
  11. 10Mechanical, Packaging, and Orderable Information

パッケージ・オプション

メカニカル・データ（パッケージ｜ピン）
サーマルパッド・メカニカル・データ
発注情報

7.3.6.2 LED Open-Circuit and Short-to-Battery Detection

The TPS92629-Q1 device has LED open-circuit detection and output short-to-battery detection. The LED open-circuit detection and output short-to-battery detection monitor the output voltage when the current output is enabled. The LED open-circuit detection and output short-to-battery are only enabled when DIAGEN is HIGH. Compared with the traditional detection method, output short-to-battery fault and LED open-circuit fault could be identified.

The TPS92629-Q1 monitors dropout-voltage differences between the IN and OUT pins for LED channel when PWM is HIGH and ADIM 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 and output short-to-battery 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 fault immediately and pulls down the fault pin firstly. 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. After the falling edge of fault pin, there is a discharge time t(discharge) to identify whether it is output short-to-battery fault or LED open-circuit fault. During the discharge stage, I(Discharge_OUT) flows into the out pin. At the end of discharge stage, the voltage difference V(INx) – V(OUTx) is compared with the internal reference voltage V(OPEN_th_falling). When V(INx) – V(OUTx) is bigger than V(OPEN_th_falling), the LED open-circuit fault is reported. Otherwise, output short-to-battery fault is reported.

The TPS92629-Q1 shuts down the output current regulation for the error channel after LED open-circuit fault or output short-to-battery 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 7-3 illustrates the timing for LED open-circuit detection, protection, retry and recovery.

GUID-20230505-SS0I-WRTR-TBLB-3QCHPJHFRK5S-low.svg Figure 7-3 LED Open-Circuit Detection and Recovery Timing Diagram

The detailed information and value of each time period in Figure 7-3 is described in TIMING section of electrical characteristics table.