Signaling out of CYPD3177 FET_EN

[Nalco]

Hi,
I'd like to signal a charging IC that i'm either running on Negociated PD Voltage/Current or a legacy charging mode,

My question is, can i use VBUS_FET_EN as a signal in this way :

I could simply use the signal to switch a fet enabling a different charging resistor

Regards,
Nicolas Fournier

[Kieran_Pan]

Hello Nalco,

In theory, this is feasible cause VBUS_FET_EN is a P-FET gate driver signal.
However, it may not work properly when connecting like above cause the driver force and value of the resistor is calculated by the Engineer.
The circuit connection of reference design of CYPD3177 and value of resistor has been verified by the Infineon. I still recommend you to connect like reference design.

Best regards,
Kieran

[Nalco]

Hi, thank you for the quick answer,
I'm still using Infineon/Cypress reference design as a basis,
But i wish to add this to signal my charge controller.

Nicolas

[Kieran_Pan · Accepted solution]

Hello Nalco,

I don't recommend you to do that cause it may not provide the driving force.
And CYPD3177 is a fixed firmware. 

You can also see the below link:
https://community.infineon.com/t5/USB-EZ-PD-Type-C/DC-characteristics-of-VBUS-FET-EN-for-BCR-CYPD713... 

Best regards,
Kieran