SLVUCP8 September   2024 TPS26750

 

  1.   1
  2.   Description
  3.   Get Started
  4.   Features
  5.   Applications
  6.   6
  7. 1Evaluation Module Overview
    1. 1.1 Introduction
    2. 1.2 Kit Contents
    3. 1.3 Specification
    4. 1.4 Device Information
  8. 2Hardware
    1. 2.1 Additional Images
    2. 2.2 Power Requirements
    3. 2.3 Setup
    4. 2.4 Header Information
    5. 2.5 Jumper Information
    6. 2.6 Push Buttons
    7. 2.7 Interfaces
    8. 2.8 Debug Information
    9. 2.9 Test Points and LEDS
  9. 3Software
    1. 3.1 Software Description
    2. 3.2 Software Installation
      1. 3.2.1 Web Browser
      2. 3.2.2 Native Application
    3. 3.3 Software Development
    4. 3.4 Using the Application Customization Tool
      1. 3.4.1 Default View
      2. 3.4.2 Selecting a Configuration
      3. 3.4.3 Filling Out the Questionnaire
      4. 3.4.4 Advanced Configuration Mode
      5. 3.4.5 Flashing Configuration to TPS26750
      6. 3.4.6 Additional Settings
        1. 3.4.6.1 Generating a New Configuration
        2. 3.4.6.2 Exporting and Importing Settings
        3. 3.4.6.3 Generating the Binary
        4. 3.4.6.4 Generating the VIF File
  10. 4Application Specific Use Cases
    1. 4.1 Liquid Detection and Corrosion Mitigation Overview
      1. 4.1.1 Liquid Detection and Corrosion Mitigation Hardware Setup
      2. 4.1.2 Liquid Detection and Corrosion Mitigation Software Setup
      3. 4.1.3 Liquid Detection Detailed Implementation
        1. 4.1.3.1 Liquid Detection Config Register (0x98)
    2. 4.2 Use With the BQ25756EVM
      1. 4.2.1 Hardware Setup with BQ25756EVM
      2. 4.2.2 Software Setup with the BQ25756EVM
  11. 5Hardware Design Files
    1. 5.1 Schematics
    2. 5.2 PCB Layouts
    3. 5.3 Bill of Materials (BOM)
  12. 6Additional Information
    1. 6.1 Trademarks
    2. 6.2 Electrostatic Discharge Caution
    3. 6.3 Terminology
    4. 6.4 Device Support
      1. 6.4.1 Third-Party Products Disclaimer
      2. 6.4.2 Supplemental Content
    5. 6.5 Documentation Support
    6. 6.6 Receiving Notification of Documentation Updates
    7. 6.7 Support Resources

4.1.3 Liquid Detection Detailed Implementation

The USBCPD Application Customization Tool allows the user to configure the number of samples, timing, and hysteresis voltage range of liquid detection to fit with the system requirements. Increasing the number of samples and timing can result in more accurate readings, but can take longer for the detection cycle to be completed. Conversely, decreasing the number of samples and timing can allow the PD to be able to detect liquid faster but can produce higher levels of false detections. This section goes through every Liquid Detection related register and field on the TPS26750, example configurations with scope captures, and recommendations for optimizations to accuracy, power consumption, and systems with an external microcontroller. For more details on register mapping, refer to the TPS26750 Technical Reference Manual.

Interrupt Event/Mask/Clear for I2C1 (Registers 0x14/0x16/0x18)

The interrupt event, interrupt mask, and interrupt clear register is intended for systems with an external microcontroller acting as the I2C controller to the TPS26750 acting as the I2C target. The interrupt mask is initialized and configured through the USBCPD Application Customization Tool. The Liquid Detection interrupt event [60] asserts when the PD controller detects an unknown short through the GPIO/SBU measurement pin. If this event is asserted, then the voltage reading on the GPIO or SBU line has cleared the Dry threshold and the PD assumes liquid is present on the USB Type-C connector. When an I2C interrupt event is asserted, the microcontroller reads the Interrupt Event (0x14) register to determine which events have triggered. After the microcontroller has read the events and performed any necessary actions, the microcontroller can clear the interrupt event by writing a ‘1’ to the asserted event in the Interrupt Clear (0x18) register. TI highly recommends to have the interrupt masking set through the USBCPD Application Customization Tool and included in the GUI generated configuration file (either binary or C array). The masking can be modified on the fly when PD is in operation, but this is not recommended.

GPIO Config (Register 0x5C)

The GPIO Config register allows the user to configure the GPIO pins of the TPS26750. In total, there are four required GPIOs for the liquid detection function to work properly and one optional GPIO event to indicate if liquid is detected (similar to the interrupt event). GPIO Config needs to be configured through the USBCPD Application Customization Tool and included in the GUI generated configuration file (either binary or C array), GPIOs cannot be modified on the fly when the PD is already in operation (after the configuration is loaded at boot). These GPIOs are configured automatically when selecting Yes to Question 8 in the Questionnaire, however further detail is provided below for assistance with debugging and design.

GPIO4 and GPIO5 are tied to the SBU pins of the USB Type-C connector (with the TPD4S480 in between the aforementioned GPIO pins and the SBU pins of the Type-C connector). These GPIOs are multiplexed to the ADC functionality to measure the voltage on the SBU measurement pins. Both GPIO4 and GPIO5 must have the Multiplexing for GPIO 4/5 Pin [1:0] field set for Pin Multiplexed to ADC (0x1) and the GPIO 4/5 Analog Input Control [228/9] needs to be set to Pin to ADC (0x1). GPIO4 and GPIO5 are not configurable for custom designs. For the liquid detection feature to function, these are required to be set as the ADC pins connected to the SBU pins on the USB Type-C connector.

GPIO6 and GPIO7 are tied to the gate pins of the PMOS and NMOS FETs, respectively. GPIO6 (connected to the PMOS gate) needs to set the GPIO Mapped Event [343:336] as LIQUID_PMOS_CONTROL (155) and GPIO7 (connected to the NMOS gate) needs to set the GPIO Mapped Event [351:344] as LIQUID_NMOS_CONTROL (156).

An optional GPIO event LIQUID_DETECTED (157) can be tied to any available GPIO pins. If configured, then the specific GPIO outputs high when the PD enters a Liquid Detected state and goes low when the PD exits the Liquid Detected state (similar to the interrupt event Liquid Detection). The TPS26750EVM sets GPIO1 by default to the LIQUID_DETECTED (157) event when selecting Yes to Question 8 in the Questionnaire.