SNAS806 September   2020 TPL1401

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  Timing Requirements: I2C Standard Mode
    7. 6.7  Timing Requirements: I2C Fast Mode
    8. 6.8  Timing Requirements: I2C Fast Mode Plus
    9. 6.9  Typical Characteristics: VDD = 1.8 V (Reference = VDD) or VDD = 2 V (Internal Reference)
    10. 6.10 Typical Characteristics: VDD = 5.5 V (Reference = VDD) or VDD = 5 V (Internal Reference)
    11. 6.11 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 Digital Potentiometer (Digipot) Architecture
        1. 7.3.1.1 Reference Selection and Digipot Transfer Function
          1. 7.3.1.1.1 Power Supply as Reference
          2. 7.3.1.1.2 Internal Reference
      2. 7.3.2 Digipot Update
      3. 7.3.3 Nonvolatile Memory (EEPROM or NVM)
        1. 7.3.3.1 NVM Cyclic Redundancy Check
          1. 7.3.3.1.1 NVM_CRC_ALARM_USER Bit
          2. 7.3.3.1.2 NVM_CRC_ALARM_INTERNAL Bit
      4. 7.3.4 Power-On Reset (POR)
      5. 7.3.5 Software Reset
      6. 7.3.6 Device Lock Feature
    4. 7.4 Device Functional Modes
      1. 7.4.1 Power Down Mode
    5. 7.5 Programming
      1. 7.5.1 F/S Mode Protocol
      2. 7.5.2 I2C Update Sequence
      3. 7.5.3 Address Byte
      4. 7.5.4 Command Byte
      5. 7.5.5 I2C Read Sequence
    6. 7.6 Register Map
      1. 7.6.1 STATUS Register (address = D0h) (reset = 000Ch or 0014h)
      2. 7.6.2 GENERAL_CONFIG Register (address = D1h) (reset = 01F0h)
      3. 7.6.3 PROTECT Register (address = D3h) (reset = 0008h)
      4. 7.6.4 DPOT_POSITION Register (address = 21h) (reset = 0000h)
      5. 7.6.5 USER_BYTE1 Register (address = 25h) (reset = 0000h)
      6. 7.6.6 USER_BYTE2 Register (address = 26h) (reset = 0000h)
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 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 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support 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 Detailed Design Procedure

The TPS92692 data sheet provides the equation for the voltage required to set a given LED current limit. Use a sense resistor of 1-Ω for the TPS92692.The voltage at the IADJ pin, VIADJ, must be 1.4 V for an LED current of 100 mA. The range for VIADJ is 2.5 V. Enable the internal reference with 2x gain to set the digipot output range to 2.42 V that will fairly be in the range of current adjustment for the LED driver. Calculate the code needed to set the digipot output to 1.4 V using the following equation:

Equation 3.

The hex value for 148 is 0x94. Shift this value by 4 bits before writing to the DPOT_POSITION register, resulting in 0x940.

The pseudocode for the programmable current limit application is as follows:

//SYNTAX: WRITE <REGISTER NAME (Hex code)>, <MSB DATA>, <LSB DATA>
//Power-up the device, enable internal reference with 2x output span
WRITE GENERAL_CONFIG(0xD1), 0x11, 0xE5
//Write digipot code (12-bit aligned)
WRITE DPOT_POSITION(0x21), 0x09, 0x40
//Write settings to the NVM
WRITE PROTECT(0xD3), 0x00, 0x10