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Topic: [Resolved] Arduino compatible device prototype working on some ports not others (Read 3996 times) previous topic - next topic

ron_sutherland

I added that soft start idea on the hot plug simulation and it looks good.
http://everycircuit.com/circuit/5701401390874624
I changed the 10k to 1k, and set the P-CH model so it works sort of like the part I use, but you can change the values on the sim before closing the switch.
The P-CH MOSFET I have been using for this type of stuff is:
DMB [DIODES,DMP3098L-7] MOSFET P-CH 3.8A 30V SOT23
(DMB is the device label printed on package.)
my projects: https://github.com/epccs

liuzengqiang

Thank you so much Ron! This MOSFET will work perfectly! There will be about 0.02V max voltage across the MOSFET (VDS) when fully and supplying 200mA so it not a bit deal. One of these days I'll dig up some info on what determines this voltage in my physics books.

I have a few SOT-23-3 breakout boards so I can put this to a test once I get the parts.
Serial LCD keypad panel,phi_prompt user interface library,SDI-12 USB Adapter

liuzengqiang

More to report back. I finally removed the two 150 ohm resistors I placed inline with D- and D+. Bingo! Before removing them, with VCC disconnected from VUSB, the device is not recognized by one of the USB 3 ports (charging port) and recognized by the other. Now both recognize the device. The only remaining issue is the current spike if I connect VCC with VUSB. I'll address this issue with the P-channel enhancement MOSFET in my next board version.

Thank you both CR and Ron!
Serial LCD keypad panel,phi_prompt user interface library,SDI-12 USB Adapter

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