TUSB320HAI: About dead battery mode

Hello Kanemaru-san,

    For dead battery mode, the customer only has to connect the TUSB320HAI to the DFP capable device. Please measure the impedance from the CC pins to GND and make sure that it is closer to 5.1KOhms when the board is powered OFF. That is the only requirement, Per Type-C specification, the DFP/DRP device shall detect the Rd termination (5.1KOhms) in one of its CC pins and then provide VBUS. If you can measure Rd in our board, then the issue must be related to the DFP side.

Regards,

Diego.

Hi Diego-san,

Thank you for your prompt reply.

We will confirm whether the impedance form CC pin to GND is around 5.1kohm at EVM is powered OFF.

Regards,

Kanemaru

Hi Diego-san,

Our costumer confirmed the impedance form CC pin to GND at EVM is powered OFF.

-CC1(1pin) to GND(LP6 on EVM) is 9Mohm (0.09V)

-CC2(2pin) to GND(LP4 on EVM) is 11Mohm (0.6V)

So, those impedance is not around 5.1kohm and VBUS is not supplied to TUSB320HAIEVM(check point is “uAB_VBUS” on EVM).

Could you please let us know what the possible causes are in regards to that?

[Other information]

-EVM operate(VDD of TUSB320HAI is supplied) if they connect AC adapter(5V)

-DFP device is used only one kind so they have not tried connection of the other DFP device yet.

If you want to include other information, please let us know.

I’d greatly appreciate your verification.

Regards,

Kanemaru

Hello Kanemaru-san,

    My bad, the internal Rd terminations are implemented by transistors, so you need to apply a voltage to the cc pins in order to test the dead battery mode in order to see the impedance. Also, the EVM must be modified for this testing. Please remove FB1, so the device will not have voltage on its VDD terminal, then connect one of the CC pins to a 56KOhm pull-up resistor to 5V and measure the voltage at the CC pin. Please post the measurements on both CC pins.

Regards,

Diego.

Hi Diego-san,

Thank you for your response.

I understand that we can use the dead battery mode(so UFP mode) when VDD isn’t applied if we remove FB1.

Is my understanding correct?

And, I have one more question.

According to your comment, I understand it is OK, if the voltage of CC1 or CC2 pin is around 0.4V.

Is my understanding correct?

Regards,

Kanemaru

Hi Diego-san,

Thank you for your reply.

I will contact you when I get new information.

Regards,

Kanemaru

Hi Diego-san,

Thank you for your response.

I will contact you if there is anything.

Regards,

Kanemaru