SLVSFU7B July   2022  – April 2024 TPS929240-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Timing Requirements
    7. 5.7 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Device Bias and Power
        1. 6.3.1.1 Power Bias (VBAT)
        2. 6.3.1.2 5V Low-Drop-Out Linear Regulator (VLDO)
        3. 6.3.1.3 Undervoltage Lockout (UVLO) and Power-On-Reset (POR)
        4. 6.3.1.4 Power Supply (SUPPLY)
        5. 6.3.1.5 Programmable Low Supply Warning
      2. 6.3.2 Constant Current Output
        1. 6.3.2.1 Reference Current with External Resistor (REF)
        2. 6.3.2.2 64-Step Programmable High-Side Constant-Current Output
      3. 6.3.3 PWM Dimming
        1. 6.3.3.1 PWM Generator
        2. 6.3.3.2 PWM Dimming Frequency
        3. 6.3.3.3 Blank Time
        4. 6.3.3.4 Phase Shift PWM Dimming
        5. 6.3.3.5 Linear Brightness Control
        6. 6.3.3.6 Exponential Brightness Control
      4. 6.3.4 FAIL-SAFE State Operation
      5. 6.3.5 On-Chip, 8-Bit, Analog-to-Digital Converter (ADC)
        1. 6.3.5.1 Minimum On Time for ADC Measurement
        2. 6.3.5.2 ADC Auto Scan
        3. 6.3.5.3 ADC Error
      6. 6.3.6 Diagnostic and Protection in NORMAL State
        1. 6.3.6.1  VBAT Undervoltage Lockout Diagnostics in NORMAL state
        2. 6.3.6.2  Low-Supply Warning Diagnostics in NORMAL State
        3. 6.3.6.3  Supply Undervoltage Diagnostics in NORMAL State
        4. 6.3.6.4  Reference Diagnostics in NORMAL state
        5. 6.3.6.5  Pre-Thermal Warning in NORMAL state
        6. 6.3.6.6  Overtemperature Protection in NORMAL state
        7. 6.3.6.7  Overtemperature Shutdown in NORMAL state
        8. 6.3.6.8  LED Open-Circuit Diagnostics in NORMAL state
        9. 6.3.6.9  LED Short-Circuit Diagnostics in NORMAL state
        10. 6.3.6.10 Single-LED Short-Circuit Detection in NORMAL state
        11. 6.3.6.11 EEPROM CRC Error in NORMAL state
        12. 6.3.6.12 Communication Loss Diagnostic in NORMAL State
        13. 6.3.6.13 Fault Masking in NORMAL state
        14.       53
      7. 6.3.7 Diagnostic and Protection in FAIL-SAFE states
        1. 6.3.7.1  Supply Undervoltage Lockout Diagnostics in FAIL-SAFE states
        2. 6.3.7.2  Low-Supply Warning Diagnostics in FAIL-SAFE states
        3. 6.3.7.3  Supply Undervoltage Diagnostics in FAIL-SAFE State
        4. 6.3.7.4  Reference Diagnostics in FAIL-SAFE states
        5. 6.3.7.5  Pre-Thermal Warning in FAIL-SAFE state
        6. 6.3.7.6  Overtemperature Protection in FAIL-SAFE state
        7. 6.3.7.7  Overtemperature Shutdown in FAIL-SAFE state
        8. 6.3.7.8  LED Open-Circuit Diagnostics in FAIL-SAFE state
        9. 6.3.7.9  LED Short-Circuit Diagnostics in FAIL-SAFE state
        10. 6.3.7.10 Single-LED Short-Circuit Detection in FAIL-SAFE state
        11. 6.3.7.11 EEPROM CRC Error in FAIL-SAFE State
        12. 6.3.7.12 Fault Masking in FAIL-SAFE state
        13.       Diagnostics Table in FAIL-SAFE State
      8. 6.3.8 OFAF Setup In FAIL-SAFE state
      9. 6.3.9 ERR Output
    4. 6.4 Device Functional Modes
      1. 6.4.1 POR State
      2. 6.4.2 INITIALIZATION state
      3. 6.4.3 NORMAL state
      4. 6.4.4 FAIL-SAFE state
      5. 6.4.5 PROGRAM state
    5. 6.5 Programming
      1. 6.5.1 FlexWire Protocol
        1. 6.5.1.1 Protocol Overview
        2. 6.5.1.2 UART Interface Address Setting
        3. 6.5.1.3 Status Response
        4. 6.5.1.4 Synchronization Byte
        5. 6.5.1.5 Device Address Byte
        6. 6.5.1.6 Register Address Byte
        7. 6.5.1.7 Data Frame
        8. 6.5.1.8 CRC Frame
        9. 6.5.1.9 Burst Mode
      2. 6.5.2 Registers Lock
      3. 6.5.3 Register Default Data
      4. 6.5.4 EEPROM Programming
        1. 6.5.4.1 Chip Selection by Pulling REF Pin High
        2. 6.5.4.2 Chip Selection by ADDR Pins Configuration
        3. 6.5.4.3 EEPROM Register Access and Burn
        4. 6.5.4.4 EEPROM PROGRAM State Exit
    6. 6.6 Register Maps
      1. 6.6.1 BRT Registers
      2. 6.6.2 IOUT Registers
      3. 6.6.3 CONF Registers
      4. 6.6.4 CTRL Registers
      5. 6.6.5 FLAG Registers
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Smart Rear Lamp with Distributed LED Drivers
      2. 7.2.2 Design Requirements
      3. 7.2.3 Detailed Design Procedure
      4. 7.2.4 Application Curves
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Receiving Notification of Documentation Updates
    2. 8.2 Support Resources
    3. 8.3 Trademarks
    4. 8.4 Electrostatic Discharge Caution
    5. 8.5 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • DCP|38
Thermal pad, mechanical data (Package|Pins)
Orderable Information

6.3.4 FAIL-SAFE State Operation

The TPS929240-Q1 supports independent channel brightness control through the FlexWire interface. The brightness of each channel is adjustable according to its DC current register IOUTXn, PWM duty cycle register PWMOUTXn/PWMLOWOUTXn and channel enable register ENOUTXn setting. The brightness of each channel reflects to its register setting value immediately after register is successfully updated through the FlexWire interface by master unit. However, the master unit loses the control for all current channels if the FlexWire communication fails between master unit and the TPS929240-Q1. For example, the interface cable is broken by accident. As a consequence, the brightness for all output channels of the TPS929240-Q1 are stuck and the ON and OFF control for all output channels are missed too. To keep the basic ON and OFF control for each output channels, the TPS929240-Q1 provides a FAIL-SAFE state when the communication to master is lost. For detailed description for FAIL-SAFE state entering and quitting criteria, refer to Device Functional Modes.

When the TPS929240-Q1 is entering FAIL-SAFE state, all the registers are set to default value or reloaded from EEPROM including IOUTXn, PWMOUTXn, PWMLOWOUTXn and ENOUTXn. The pre-programmed settings in the EEPROM are loaded and the corresponding registers are reset to the default values. The TPS929240-Q1 provides two hardware input pins, FS0 and FS1 to turn on or off corresponding current output channels in FAIL-SAFE state. Each current output channel has its own register, FSOUTXn to set the mapping to FS0 or FS1. When FSOUTXn is set to 0, the corresponding current output channel is controlled by FS0 input, otherwise it is controlled by FS1 input. If the voltage of FSx input is higher than its high threshold, VIH(IO), all current output channels mapped to FSx input are turned on. When the voltage of FSx input drops below low threshold, VIL(IO), all current out channels mapped to FSx input are turned off. The flag register FLAG_EXTFSx shows the FSx input level at real-time. If FSx pin input voltage is logic high, the FLAG_EXTFSx is set to 1. All FSOUTXn registers load their corresponding EEPROM data when the TPS929240-Q1 enters FAIL-SAFE state.

The PWM generator and phase shift dimming are both supported in FAIL-SAFE state. Figure 6-6 is the signal path diagram for PWM generator in FAIL-SAFE state.

GUID-20200917-CA0I-3K46-FBPC-BDZM1QR3CT2K-low.svg Figure 6-6 Output Current Control Path in FAIL-SAFE State

The FAIL-SAFE state also allows the TPS929240-Q1 operating as a standalone device without master controlling in the system. The ERR pin is used as a fault indicator to achieve one-fails-all-fail or one-fails-others-on diagnostics requirement. When low quiescent current in fault mode is required, the device must be set as one-fails-all-fail. In this case, if fault is triggered, the device goes into low current fault mode.