This user’s guide compares the features of the INA219 and INA232 digital power monitors, and outlines key differences that need to be considered when migrating from INA219 to INA232. A design example is used to highlight both commonalities and differences between the two. The example demonstrates that there are a range of applications that can be served by both devices, either to solve a supply chain constraint issue or simply to upgrade to the latest product offerings from TI. For applications that require features unique to one device, substituting one device with the other device is not always possible.
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A digital power monitor is specially designed for current sensing applications, with an integrated analog-to-digital converter that is able to withstand common-mode voltages that are much higher than the device power supply itself. As a result, the digital power monitor can be directly interfaced with the circuit being measured.
Digital power monitors extract the small differential shunt voltage from a normally high common-mode voltage rail. This shunt voltage is proportional to the load current supplied by the voltage rail. The common mode (Bus) voltage is also measured. With these two measurements, the power monitors calculate the current, voltage, and power. These quantities are available as bit streams and available through the digital interface. Figure 1-1 shows a block diagram of a typical power monitor with I2C digital interface.