SBOS644C February 2013 – March 2018 INA231
The INA231 measures the voltage developed across a current-sensing resistor (RSHUNT) when current passes through the resistor. The device also measures the bus supply voltage, and calculates power when calibrated. The INA231 comes with alert capability, where the alert pin can be programmed to respond to a user-defined event, or to a conversion-ready notification. This design illustrates the ability of the alert pin to respond to a set threshold. In this case, a 10 A are pulled through a 2-mΩ shunt resistor, generating a 20-mV shunt voltage drop that is measured by the INA231. The bus supply is 12 V, and the BUS pin is tied to the IN– pin, so that the power loss through the shunt resistor, however small, is not added to the power calculation performed by the INA231. This configuration provides an accurate measurement the power dissipated by the load.