INA219 DC Current Sensor Question

[lunarcrusader]

Hi,

First post since joining 4 years ago :P, Right now I am trying to do some measurements on a sensitive device using a power supply to power the device. I noticed that without the +/- VIN, but the SDA/SCL, VCC and GND plugged in (5V and GND from the Arduino UNO) I get ~1V from the +VIN. Is this normal? I have tried it on two of the INA219 that I have and the results are the same.

If I power the device directly from the power supply it will turn on, but if I go through the INA219 it will not turn on.

thanks,
LC

[Franklin97355]

Could you post a drawing or picture of your connections?

[lunarcrusader]

picture attached, I measured from VIN+ to GND with a regular DMM and get about ~1.05V

[lunarcrusader]

Here is how it is fully connected, I used the LED as an example of the device and the DC jack as the PS.

[Franklin97355]

The connections look correct. what are you powering the device with and what is the device?

[lunarcrusader]

It's a old phone that I have, I dissected the battery connector and took the +/- and hooked up the Agilent PS to it. That is not an issue though, with the 1V on the -VIN, it causes the device not to boot because it thinks there is still power going to it instead of going to 0V. Just want to know if it is normal for the INA219 to have power supplied to the -VIN even though there is no +VIN.

[adafruit2]

there might be a diode leakage thru the ADC sensor in the INA219 - so its not unreasonable to see a small voltage on those pins if they are not powered

[lunarcrusader]

seems like that is the case :/ wish it was there but what can you do right? :P I implemented a switch to toggle the GND from the Arduino board as a work around for now.

thanks
LC