CX3 SUPPLY when USING USB and external supply

[D_BROW]

Hello,

I am currently designing a PCB with the CX3 processor.

the board is powered by an external power supply V5V_EXT.

Could you please tell me how to connect the USB connector that comes on the board?

I thought of connecting VUSB from the connector to the VUSB pin of the CX3.

As for the other power supplies of the core, they will be generated from the V5V_EXT power supply.

The problem is that in this case we can not respect the sequence of POWER ON
because if the USB cable is not connected and we are only supplied with external power the sequence described in this graphic is not respected!

Could you please tell me how to power the board to respect the power sequence of the CX3.

For information we are in USB 3.0.

Thank you @

@Rashi_Vatsa 

[JayakrishnaT_76 · Accepted solution]

Hello,

Can you please refer to the schematics of Denebola RDK and let us know if you still have any queries? The schematics of Denebola RDK can be downloaded from the following link:

https://www.e-consystems.com/CX3-RDK-Documents.asp

[D_BROW]

Hello,

Thank you for your feedback.

According to your evaluation board you used an SPDT to have a P5V_EXT or VUSB power supply on your board.

Can we use an integrated circuit to manage the priorities, in order to have an autonomous Board ?

Thank you in advance for your answer.

[Rashi_Vatsa]

Hello,

Yes, you can manage the priorities to meet the power-up sequence as in the CX3 datasheet.

[D_BROW]

Hello,

For our use case we want to supply the product with an external power supply. However, we can get the information from the CX3 when we connect the USB cable.

can we use a GPIO of the CX3 to have the information about the connection of the USB cable?

Can we power the PIN VUSB exclusively by an external P5V_EXT.

Did you have any feedback about this manipulation regarding USB3.0 performances ?

Thank you in advance for your support !