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I need to disable the CYPD3177 to provide power from an external barrel power connector. I intend this power to come in after the pass fets that are controlled by VBUS_FET_EN. Can the VBUS_FET_EN be used for this purpose? Is there an alternate method?
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Hello,
Yes, this could work looking at the VGS(th) of your FET.
-You could use a power OR-ing method as well or a SPDT switch between the FETs and external power supply. This would take care of the back-powering in case the host is also connected.
-Could you please let us know how the BCR is powered?
Best Regards,
Sananya
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Hi,
It is not possible to control the FETs using VBUS_FET_EN through a HPI command from an EC. Could you please let us know when you would like to disable the BCR and provide power directly?
Best Regards,
Sananya
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I would like to provide power directly before the usb cable is connected and the rest of the pcb is off. I also want to make sure it is safe and will not back drive the host when connected. In terms of the circuit to use VBUS_FET_EN, I was thinking of doing this...
Where J1 Is just a 2 pin jumper, which is open when I want to use usb power and closed when I want to power directly from external source.
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Hello,
Yes, this could work looking at the VGS(th) of your FET.
-You could use a power OR-ing method as well or a SPDT switch between the FETs and external power supply. This would take care of the back-powering in case the host is also connected.
-Could you please let us know how the BCR is powered?
Best Regards,
Sananya