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View Full Version : Current, voltage and circuit question


dmacpro91
Jan 11, 2014, 06:46 PM
This is my first post here and I don't think I've missed anything, but want to clarify something. I have a project where I need to power 2 5v devices. I have a 5v 1 amp power supply (this is dc btw). I am able to power the devices, but some of the signaling seems inaccurate every now and then. One device is a BLE Mini (BLE Mini — RedBearLab (http://redbearlab.com/blemini/)) and the other is the V2Dip1-32 (http://www.ftdichip.com/Support/Documents/DataSheets/Modules/DS_V2DIP1-32.pdf). The way the power connection is setup is like this:

5v 1 amp source + -> VCC V2Dip1 -> VIN BLE Mini
5v 1 amp source - -> GND V2Dip1 -> GND BLE Mini

Would it make a difference if I powered these devices like this:
________________-> VCC V2Dip1
5v 1 amp source +
________________-> VIN BLE Mini


________________-> GND V2Dip1
5v 1 amp source -
________________-> GND BLE Mini

The signaling seems to be fine when each device is on its own power source.

I am getting a multimeter to verify the current for each device to make sure it's not trying to pull too much. Could this signal corruption be an issue with the chips being close to each other (not touching)? Would a ferrite bead help? I can code software all day, but dealing with the hardware is new to me. Thanks in advance for any help.

hfcarson
Jan 14, 2014, 05:12 AM
Connect the power supply as directed by the instructions for each device...
To correct the signaling errors, try to separate the devices to where they cannot interact.
Is the power supply a good stiff source? That is, does the supply vary at all?
Good luck to you,