SDAA491 October   2026 TPS25751A , TPS25752A , TPS26750A

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
    1. 1.1 What is Liquid Detection and Why is It Needed?
    2. 1.2 Definitions
    3. 1.3 Liquid Detection Method Overview
  5. 2Detailed Description
    1. 2.1 Hardware Implementation and Requirements
      1. 2.1.1 GPIO Hardware Requirements
    2. 2.2 Firmware Implementation and Requirements
      1. 2.2.1 Interrupt Event/Mask/Clear for I2C1 (register 0x14/0x16/0x18)
      2. 2.2.2 GPIO Configuration (register 0x5c)
      3. 2.2.3 Liquid Detection Configuration (register 0x98)
        1. 2.2.3.1 Wait Timing
          1. 2.2.3.1.1 Wait Time in Seconds Non-Liquid [7:0]
          2. 2.2.3.1.2 Wait Time in Seconds Liquid [15:8]
        2. 2.2.3.2 Sample Timing and Retires
          1. 2.2.3.2.1 Sample Time in 10ms No Liquid [19:16]
          2. 2.2.3.2.2 Sample Time in 10ms Liquid [23:20]
          3. 2.2.3.2.3 Liquid Detection Retries Wait Time [27:24]
          4. 2.2.3.2.4 Liquid Detection Retries [31:28]
          5. 2.2.3.2.5 Number of Samples [39:32]
        3. 2.2.3.3 High and Low Threshold Measurements
          1. 2.2.3.3.1 Low Threshold ADC No Liquid [47:40]
          2. 2.2.3.3.2 High Threshold ADC No Liquid [55:48]
          3. 2.2.3.3.3 Low Threshold ADC Liquid [63:56]
          4. 2.2.3.3.4 High Threshold ADC Liquid [71:64]
        4. 2.2.3.4 Enable Liquid Detection [72]
        5. 2.2.3.5 Enable Corrosion Mitigation [73]
        6. 2.2.3.6 Monitor During Attach [74]
        7. 2.2.3.7 Monitor During Unattached [75]
        8. 2.2.3.8 Liquid Pins to Monitor [77:76]
        9. 2.2.3.9 Pulldown Threshold ADC [87:88]
  6. 3Detailed Application Procedure
    1. 3.1 Example Liquid Detection Configuration
    2. 3.2 Application Performance Plots
      1. 3.2.1 Number of Samples Waveform
      2. 3.2.2 Sample Time in No Liquid Waveform
      3. 3.2.3 Sample Time in Liquid Waveform
      4. 3.2.4 Wait Time in No Liquid Waveform
      5. 3.2.5 Wait Time in Liquid Waveform
      6. 3.2.6 Entering Liquid Detection Waveform
      7. 3.2.7 Exiting Liquid Detection Waveform
      8. 3.2.8 Corrosion Mitigation Disabled Waveform
  7. 4Summary
  8. 5References

2.2.3 Liquid Detection Configuration (register 0x98)

The Liquid Detection Configuration register contains all the configurable settings for liquid detection including-
  • Number of samples
  • Timing between sampling
  • Hysteresis range for entering and exiting liquid detected state
  • Enable bits for liquid detection and corrosion mitigation

  • Enable bits for monitoring during an attached.SNK/attached.SRC state or unattached.SNK/unattached.SRC state

In order to enabled the deafult configuratrion for the liquid detection feature, Question 8 of the Application Cusatimization Tool questionare must be set to "Yes". To perform any modifcations to the defualt settings, the user will need to enter "Advance Mode" within the GUI tool. See the USBCPD Application Customization Tool User Guide Table 4-9 for the default configuration settings used for the TPS25751A, TPS25752A, and TPS26750A.

The configuration settings discussed in the following section is be found in the Application Customization Tool.