How to 3.3V with more than 250mA

U

Uija

Well-known member
Hey!

I am working on a project where I have several devices, that work on 3.3V, that talk to each either over Serial or I2C, so I would love to have them all on the same 3.3V level, so I don't have to mess around with disconnecting them with a optocoupler. Sadly I might exceed the 250mA, that the Teensy is willing to deliver. Any idea, what I can do? I think, that connecting the TX of the Teensy with its own 3.3V to a RX on another device, that has its own 3.3V might cause issues?!

Jens
 
Teensy pins can tolerate ±0.3 volt difference, so as long as your two 3.3V power supplies are within 0.3 volts of each other, it should be fine.

Well, except for startup or shutdown where one supply may turn on before the other. That's more difficult...
 
Well, except for startup or shutdown where one supply may turn on before the other. That's more difficult...
Click to expand...
Would not one of these not help to sort that problem?
Tie the output disable to a resistor network supplied by the 3.3V line.
The voltage regulator turns on when the Vdis line reaches 2V. So when Teensy 3.3V reaches 3V the input to the regulator Vdis line needs to be 2V.

EDIT: Another alternative might be to use a Teensy output to turn on the regulator.
If you do this you would need to check the default power up state of the Teensy pins.
 
You must log in or register to reply here.
Back
Top