LPC MicrocontrollersのトピックUSB0_VBUS active components

USB0_VBUS active components

lpcware — Wed, 15 Jun 2016 16:51:11 GMT

Content originally posted in LPCWare by tvink on Wed Mar 18 13:38:38 MST 2015
Hi,

Having trouble reading section 22.5.1 in the LPC18xx users manual.

I am using USB0 for a device connection with a type A connector. My unit can be USB powered.
The paragraph says that I may need to add active components to disconnect the link when VDDIO
is not present. Not sure what that means for my application.

My VDDIO comes from an LDO hung on USB_VBUS so it may lag it a little ( probably only 10s of nanoseconds ). However
VDDIO is always present once the USB power is available.

Do I need to disconnect USB0_VBUS from the USB supplied 5V power durring the power up sequence?

Thanks

Re: USB0_VBUS active components

lpcware — Wed, 15 Jun 2016 16:51:12 GMT

Content originally posted in LPCWare by xianghuiwang on Wed Mar 18 16:30:16 MST 2015
Consider the time is very short when VDDIO lags behind VBUS, this is probably fine.
regards,

Re: USB0_VBUS active components

lpcware — Wed, 15 Jun 2016 16:51:12 GMT

Content originally posted in LPCWare by tvink on Thu Mar 19 05:23:35 MST 2015
Thanks!