LTC4150 Coulomb Counter Hookup Guide

Contributors: MikeGrusin

Resources and Going Further

Changing the Sense Resistor

The Coulomb Counter uses a sense resistor to measure current. This very small resistor (0.05 ohms) is the only component located between the input and the output. The LTC4150 measures the voltage drop across this resistor; thanks to Ohm's law the voltage drop is directly proportional to the current passing through the resistor.

We've installed an 0.05 ohm sense resistor in the Coulomb Counter, which is why the maximum current is 1A and you get 5859 "ticks" per Ah. If you want more resolution (ticks per Ah) at a lower maximum current, or want more current* at less resolution, you can replace this resistor with a different value part. You will need to remove the existing part and replace it with another surface-mount part, or use the provided footprint for a through-hole resistor. Refer to the LTC4150 datasheet for information on resistor selection. There is also a spreadsheet in the Github documentation folder that may be useful.

* Note that the PCB traces on the board are not designed to handle more than 1.6A continuously, and the JST connectors are not designed for more than 2A.

Also note that there is no easy way to increase the maximum supply voltage of 8.5V. Sorry!

Using the SHDN Input

You can reset or shut down the LTC4150 by making the SHDN input LOW. This will reduce the power consumption of the board, but the LTC4150 will not measure current consumption in this mode. This input has a pullup resistor; if you do not need shutdown functionality, you can leave this input disconnected.

We hope you find the LTC4150 Coulomb Counter useful. Now that you've successfully got your LTC4150 Coulomb Counter up and running, it's time to incorporate it into your own project! For more information, check out the resources below:

• Schematic
• Eagle Files
• Datasheet (LTC4150)
• GitHub (Example Code & Design Files)
• Product Video

Need some inspiration for your next project? Check out these related tutorials!

If you have any problems, feel free to contact our Tech Support Department. And let us know what you're using it for!