Do I need PD

[MiAu_4631556]

Hi,

I am Designing a Product using a FX3-Chip (so far everything is working fine) which will later be plugged in to a Smartphone via USB-C, and right now we are discussing the power management. We would need about 5V/2A so 10W.

Sadly the USB3.2 / 3.1 gen2 / Type-C specifications are quite unclear to me. To my Knowledge there exist (without Power Delivery) 3 Profiles with 5V (USB-C):

500-900mA    /    1,5A    /    3A  

each with different pull-up resistors on one of the cc pins.

But as far as I know there is no possibility to guarantee that a Specific Host does support all of the Profiles.

So I was thinking if we use a Smartphone which supports USB-PD we can assume that at least PD Profile 1 (Default Startup) 5V/2A is always present.

Does one still need a USB-PD Chip for using this Profile? Default Startup sounds like it is always present even without a USB-PD Chip.

If i need a USB-PD Chip can you send me a Reference Schematic using a suitable EZ-PD Chip and the FX3?

Thank you in Advance.

[Sananya_14 · Accepted solution]

Hi,

Your understanding is correct. USB Type-C specification supports upto 5V 3A and the default power profile supported by the host is determined using the Rp value on the CC lines. So for applications that require only a maximum of 5V 3A power, a PD controller is not required.

Please refer to the KBA for FX3 designs with a type-C connector.

Best Regards,

Sananya

[MiAu_4631556]

So if i want to be sure that my Host (i dont know the specific Smartphone yet) supports >2A I have to rely on PD?

In other words:

I am not able to determine the output power of a smartphone through the datasheet, they only mention USB-C with USB2.0/3.0 support nothing more specific. But If they support USB-PD i can assume that at least PD Profile 1 (Default Startup) 5V/2A is always present? To be clear i want do draw 2A from the Smartphone.

Does one still need a USB-PD Chip for using this Profile? Default Startup sounds like it is always present even without a USB-PD Chip.

Thank you in advance.

[Sananya_14]

Hello,

No, PD is not required for getting power >2A since we can get 3A in Type-C capable devices as well. However, there is no way to get 5V 2A since it is not a default profile as per the Type-C specification.

The default startup profile will depend upon the smartphone but if you are not sure about the power profiles supported and would like to be able to draw 5V 2A, you could use a PD controller. This will allow power negotiation with your smartphone and you can draw the maximum supported power.

Best Regards,

Sananya