TPS25751: How to make TPS25751SRSM output 5V/3A full power?

Hi Aiden,

aiden-kai.chen said:

  How to make TPS25751SRSM output 5V/3A full power output?

What kind of table are you connecting to and does the tablet have PD capabilities (able to negotiate PD contract)? In addition, are you able to capture PD logs so we can see what PD contracts (if any) have been negotiated? 

Sometimes even if a source (TPS25751S in this case) can supply up to 3A, a sink device may not draw the full capability of the source. A PD log will tell us if the sink requested only 1.5A or 3.0A. 

Thanks and Regards,

Raymond Lin

Hi Raymond,

    Sorry late for replying. Our TPS25751S capture PD contracts is PD3.0-15W.

    The tablet is ASUS Fearless 2 in 1(T3300).It have 2x USB3.2 Gen2 Type C support USB PD. The tablet charger can provide 20V DC, 3.25A, 65W.

    I suppose sink just need 1.5A.

    How can I get the TPS25751S as source output 3A current? Is there any easy way to do this？ Thanks.

Hi Aiden,

Do you have a PD log? how are you determining the tablet the output power is 1.5-A?

Couple things to check:

1. Check the type-C current in the Port Control (0x29) register and make sure it is set to 3-A

2. Check source PDO 1 and make sure current is set to 3-A

If these are both set properly, the limited current could be due to some system state of the tablet. You would need to get a PD log to confirm the messaging on the type-C port to see if it is requesting a lower power PD contract.

Thanks and Regards,

Chris

Hi Chris,

    We use Power-Z KM003C monitor the USB-PD protocol and output voltage/current/power information.

    Check current config:

Hi Aiden, 

If you can send us the PD log captured from the Power-Z KM003C we can take a look on our end. From all the settings you've shown us, there should no issues with the configuration. We'll need to see from the PD log why current draw is low. 

Thanks and Regards,

Raymond Lin