FTDI disappears when powering circuit with it.

Question

I'm trying to us the ESP8266 wifi board and when I power it over the 3.3v out on the FTDI the entire usb disappears from ubuntu. as soon as I take the power away it shows back up again. What could cause the /dev/ttyUSB to disappear when using the power from the FTDI?

Answer 1

The 3.3V regulator on a ft232 is not that strong. 50 mA or so at best. The ESP is very power hungry compared to it. You need a better regulator. This is to say, the regulator on the FTDI is being overloaded, and the whole thing is losing power, essentially brown outs. The FTDI runs off the 3.3v internally, so when the regulator starts failing to regulate due to being overloaded, the internal circuitry cuts out.

Answer 2

I've had this issue when I first used the module on Windows 7. It is not OS related, just a power limitation as @Passerby answered.

You neeed to power the ESP8266 with something else, other than the FTDI 3.3v. Here are some options to deal with this, that worked fine for me:

• 2 AA bateries;

• a 3.7V cellphone/tablet/whatever battery; since a fully charged battery can have around 3.9v (or a little more), use a diode in series with the positive pole, to drop 0.6v;

• wall outlet, obviously rated 3.3v.

One important point here is to connect the grounds together (GND, -V, you name it).

Bonus: I made a mini board to flash my ESP, and just yesterday I connected the +5v from the FTDI to an AMS 1117 3v3 regulator, it is working pretty fine and smooth for me.

The idea is that the +5v comes directly from the USB port, which gives us more than enough power (500mA in the worst case scenario).

Although it worked for me, I can't guarantee it would work for every available adapter. Still, I think it is worth the try.