TPS65981: PP_5V Current Limit

Julian Chen

Expert 2550 points

Part Number: TPS65981

Hi E2E,

We use TPS65981 as a USB host and set USB 5V current limit 0.5A, just like below,

But we test it then find that can't trigger current limit until 1.3A.

Did we have something wrong about setting?

Thanks!

over 6 years ago

0 Eric Beljaars over 6 years ago

TI__Mastermind 36756 points

Hi Julian,

The TPS65981 is a Type-C/PD controller. It is likely that you are entering a Type-C Implicit contract where the controller will have to offer a minimum of 0.9A. The 1.3A overcurrent trip is expected for this scenario.

Thank you,
Eric

0 Julian Chen over 6 years ago in reply to Eric Beljaars

Expert 2550 points

Hi Eric,

How to set PP_5V0 current limit setting 0~15?
In our desing,USB_5V share from PA_5V,I want to make sure our setting is “0”,limit USB_5V maximum current to 1.3A.
Reserve enough current margin for PA_5V.

0 Eric Beljaars over 6 years ago in reply to Julian Chen

TI__Mastermind 36756 points

Hi Julian,

Unfortunately, this would be non-compliant to the USB-C specification and the TPS65981 cannot support this unless the device has entered a PD contract. You can set the Type-C Current to either 0.9A, 1.5A, or 3A in the System Configuration register (0x28).

Thanks,
Eric

0 Julian Chen over 6 years ago in reply to Eric Beljaars

Expert 2550 points

Hi Eric,

we read the 0X28, and shows the values as below,

What current limit did it set?

0 Eric Beljaars over 6 years ago in reply to Julian Chen

TI__Mastermind 36756 points

Hi Julian,

You can set the current limit for Type-C implicit contracts in the 0x28 System Configuration Register. If you click on the tab on the left side of your screen that is labeled "System Configuration" you can set the Type-C Current.

Thanks,
Eric

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TPS65981: PP_5V Current Limit