FTDI Community

General Category => Discussion - Hardware => Topic started by: adrian on October 09, 2020, 10:38:39 AM

Title: FT230X USB Bus Powered with Power Switching Configuration
Post by: adrian on October 09, 2020, 10:38:39 AM

Hello,

In the FT230X datasheet, there is an application description with switching the usb power with a MOSFET. I am wondering if this circuit actually works. I think it would just work if the CBUS3/PWREN# output switches between output low and hi-Z. But i couldn't find anywhere in the datasheet a description that this happens. If the output just switches to output high, the 3.3 V IO voltage wouldn't be enough to switch the MOSFET.

I am wondering how it works?

Title: Re: FT230X USB Bus Powered with Power Switching Configuration
Post by: FTDI Community on October 09, 2020, 04:36:16 PM

Hello

Please see TN_162 Bus Powered with Power Switching Configuration (https://www.ftdichip.com/Support/Documents/TechnicalNotes/TN_162%20Bus%20Powered%20with%20Power%20Switching%20Configuration.pdf) which should help.
   
Best Regards,
FTDI Community

Title: Re: FT230X USB Bus Powered with Power Switching Configuration
Post by: adrian on October 12, 2020, 07:29:27 AM

Hello,

Okay, thanks. This document confirms my suspicion. The circuit "Bus Powered with Power Switching Configuration" in Figure 6.3 in the FT230X datasheet doesn't work.

Best Regards,
Adrian