Tuesday, February 10, 2015

Current Measurement Tool (INA219)

Current Measurement Tool(INA219)

Current measurement for board evaluation requires quite expensive tools and not so easy to log the data over time. So for the quick test and estimation of the system power consumption, I wanted to bring up a tool that I can easily use without taking so much space of my desk
. The easiest way that I was thinking is to use instrumental amplifier or something to measure the voltage difference between a small resistance and feed the analog output to the ADC in a MCU. MCU can log the data and send the data to host PC through USB or other interface.I have a Arduino UNO board that I got long time ago, and it was just sitting on my desk... so I thought it would be a great opportunity to use the board to test this tool. 
Fortunately, I found a chip INA219 that has I2C support with built-in analog front-end and ADC, so it makes this bring up so easy and decided to use this chip with Arduino.

http://www.ti.com/product/ina219

Instead of building a board, I decided to use cheap breakout board that is available.

This breakout board is actually tested with Arduino and all the instruction is available in the link below.
https://learn.adafruit.com/adafruit-ina219-current-sensor-breakout




I measured 5V trace of one of my board and it shows the current between the shunt resistor.

The measured numbers can be displayed using Tera Term.




Hardware:
    Arduino UNO
    INA219 Breakout board
   
Summary:
INA219 is very easy to use . I would consider using for the other board evaluations. Evaluation board is available at Texas Instrument site, but the cost is high. So for the quick introduction, Adafruit board with Arduino is very reasonable to start with.
http://www.ti.com/tool/ina219evm

Reference:     
http://www.ti.com/product/ina219
https://learn.adafruit.com/adafruit-ina219-current-sensor-breakout




                 

No comments:

Post a Comment