SPMU380 July   2026 TPS25730A

 

  1.   1
  2. 1Read This First
    1. 1.1 About This Manual
    2. 1.2 Notational Conventions
    3. 1.3 Glossary
    4. 1.4 Related Documents
    5. 1.5 Support Resources
    6. 1.6 Trademarks
  3. 2Introduction
    1. 2.1 Purpose and Scope
    2. 2.2 PD Controller Host Interface Description
      1. 2.2.1 Overview
    3. 2.3 Unique Address Interface
      1. 2.3.1 Unique Address Interface Protocol
  4. 3PD Controller Policy Modes
    1. 3.1 Overview
    2. 3.2 Sink Policy Mode
  5. 4Register Overview
    1. 4.1 TPS25730A Registers
  6. 54CC Task Detailed Descriptions
    1. 5.1 Overview
    2. 5.2 PD Message Tasks
      1. 5.2.1 'GSrC' - PD Get Source Capabilities
      2. 5.2.2 'GPPI' - PD Get Port Partner Information
      3. 5.2.3 'MBRd' - Message Buffer Read
    3. 5.3 System Tasks
      1. 5.3.1 'ANeg' - Auto Negotiate Sink Update
      2. 5.3.2 'DBfg' - Clear Dead Battery Flag
  7. 6User Reference
    1. 6.1 AUTO_NEGOTIATE_SINK Register
      1. 6.1.1 AUTO_NEGOTIATE_SINK Usage Example 1
      2. 6.1.2 AUTO_NEGOTIATE_SINK Usage Example 2
      3. 6.1.3 AUTO_NEGOTIATE_SINK Usage Example 3
      4. 6.1.4 AUTO_NEGOTIATE_SINK Usage Example 4
  8. 7Revision History

6.1 AUTO_NEGOTIATE_SINK Register

In general, writing to AUTO_NEGOTIATE_SINK register while a sink contract is in place does not cause an automatic renegotiation, and changes take effect the next time a contract is negotiated. The ANeg command forces a re-evaluation of this register and a new Request message is issued if appropriate.

If the first four bytes of this register are written as zero, then the PD controller always requests a 5V Fixed Suppy contract at 100mA.

The following is a high-level summary of how this register drives the PDO selection when PPS is disabled or no matching APDO is found.

  • Parse the received PDOs in the register RX_SOURCE_CAPS. Discard any PDO whose voltage range is below ANMinVoltage or above ANMaxVoltage.
  • Calculate the PDO power for each received PDO (RX_SOURCE_CAPS.SourcePdoX). Rank all PDOs according to the PDO power.
    • PDO Power = Voltage × MaximumCurrent (Fixed Supply)
    • PDO Power = MinimumVoltage × MaximumCurrent (Variable Supply)
    • PDO Power = MaximumPower (Battery Supply)
  • The PDO with maximum PDO Power that also passes the voltage check is selected. In case there are multiple PDOs that pass the voltage check and have the same maximum PDO Power, tie breakers are applied as described below:
    • A Fixed supply type is preferred, and Variable supply type is preferred over Battery supply type.
    • If the PDOs being compared have the same supply type, then ANRDOPriority specifies how to break the tie.