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TPS25730: Consultation on Power Supply Negotiation Issues and Circuit Configuration Issues

carney wang
Prodigy 40 points
Part Number: TPS25730
Other Parts Discussed in Thread: TPS25751

Regarding the power supply negotiation issue, the following questions exist:

1. When a charging adapter supporting the PD protocol is input, the TPS25730 should be able to recognize it. After a successful negotiation, the currently negotiated voltage and operational current with the charging adapter should be written into the TX_SINK_CAPS Register. In this way, the external MCU can obtain the power supply capabilities (including voltage and current capabilities) of the current charging adapter through I2C. Is the above understanding correct?

2. For a charging adapter that does not support the PD protocol (such as 5V 1A), can the TPS25730 recognize the charging capabilities (voltage and current) of the charging adapter? Can it supply power normally? If it can recognize and supply power, can the external MCU obtain this part of the information?

Circuit configuration: 1. Is it necessary to connect an external power supply to VIN_3V3? Can the TPS25730 operate normally if it is not connected? It seems that there is no connection on the EVM development board.

  • 0
    TI__Mastermind 37625 points

    您好

    已经收到了您的案例，调查需要些时间，感谢您的耐心等待

  • 0 回复 Daniel
    TI__Mastermind 30915 points

    Hi,

    carney wang 说：
    1. When a charging adapter supporting the PD protocol is input, the TPS25730 should be able to recognize it. After a successful negotiation, the currently negotiated voltage and operational current with the charging adapter should be written into the TX_SINK_CAPS Register. In this way, the external MCU can obtain the power supply capabilities (including voltage and current capabilities) of the current charging adapter through I2C. Is the above understanding correct?

    No, the TX_SINK_CAPS holds the full list of SINK Power Data Objects(PDOs) that the sink supports, it does not hold the active contract.

    You actually need a compination 

    The External MCU should check the Active_contract_pdo and  Active_contract_rdo register for the negotiated contract. The register follows the RDO format described in the USB-C PD spec which can be found in the documents section of the USB-IF site.

    The PDO register will give you the voltage and the RDO register will give you the active current.

    carney wang 说：
    2. For a charging adapter that does not support the PD protocol (such as 5V 1A), can the TPS25730 recognize the charging capabilities (voltage and current) of the charging adapter? Can it supply power normally? If it can recognize and supply power, can the external MCU obtain this part of the information?

    The TPS25730 will only support Type-C (500mA/900mA, 1.5-A and 3-A) and USB-type-c adapters. If a valid PD protocol contract is negotiated, it will store the Requested Data Object(RDO) in the Active RDO register. 

    The TPS25730 currently does not share information on connections outside of the sink PD protocol contract.

    It is possible to have a 5V/1A PD contract, so I'm not entirely sure what you protocol you are mentioning in your first sentence.

    carney wang 说：
    Circuit configuration: 1. Is it necessary to connect an external power supply to VIN_3V3? Can the TPS25730 operate normally if it is not connected? It seems that there is no connection on the EVM development board.

    No, VIN3V3 is not necessary. The TPS25730 can operate in a "Dead Battery" state, where it take power from the Type-C bus.

    Thanks and Regards,

  • 0 回复 Lydia
    Prodigy 40 points
    Regarding the second item above:

    ①Suppose this adapter does not support the PD protocol. Can the TPS25730D recognize it and charge externally?

    ②For a charger that supports the PD protocol and has only an input of 5V/3A, if the user configures the minimum voltage to 9V in the TPS25730D, can it supply power in this case?

    ③If for a charger that supports the PD protocol and can support 5V/3A, 9V/2A, 12V/2A, and the user configures the minimum voltage to 5V and the maximum voltage to 12V, which PDO will the TPS25730 give priority to in this case? Can the user set the priority?
  • +1 回复 carney wang
    TI__Mastermind 30915 points

    Hi,

    1. As mentioned before, the TPS25730 will only support Type-C contracts(5V contracts defined by CC line resistive biasing) and Type-C PD contracts.

    2. The minimum voltage is primarily for calculating Capabilities Mismatch and the TPS25730 will still supply power if the voltage negotiated is below the minimum voltage. If the minimum voltage is greater than the negotiated contract (9-V > 5-V) we will assert the Cap Mismatch bit

    3. The TPS25730 will always try to negotiate the highest power contract that both it and the charger can support. In this case it would attempt to negotiate the 12-V contract. No, the user can not set priority, the supported sink PDOs are set on power up by the ADCINx resistive dividers. If the customer is looking for more configurability, they may want to evaluate the TPS25751 family of devices. Some of the major differences are that the TPS25751 can be configured over I2C, is a Dual role power device, and requires a fw image to be loaded on bootup from an external device.

    Thanks and Regards,