Keeping an eye on battery consumption is significant for both IoT and classic portable devices. The PAC1711/PAC1811 family from Microchip provides single-channel power-monitor ICs that operate with a quiescent current of just 100 µA.

From a technical point of view, the PAC1711/PAC1811 family is shown in the figure below.

Pins VSENSE+ and VSENSE- are used to create the connection to the external shunt, across which the supply current will be led. The SCL and SDA pins implement an I2C/SMBus interface that can be easily connected to a variety of microcontrollers.

Resolution vs Power Consumption Trade-Offs for Optimal Design Performance

Microchip provides two versions of the component. The PAC1711 offers 12-bit resolution for current monitoring and consumes 100 µA. The PAC1811 requires 140 µA of power and offers 16-bit measurement accuracy. That way, designers can easily select the option best suited to the device-under-test's accuracy requirements.

Thanks to address pins, engineers can operate multiple chips in the same network. This can be useful if multiple current consumptions, for example, from different power supplies, need to be tracked simultaneously.

Highly Accurate Power Consumption Tracking

The Microchip PAC1711 / PAC1811 family is intended as a fire-and-forget solution. Designers deploy the system, set it up, and periodically return to harvest the collected power information without polling. In the data sheet, Microchip promises the following specifications for the system:

1% Power Measurement Accuracy over a Wide

Dynamic Range

• On-Chip Accumulation of 24-bit Results for Power

Measurement:

◦ 56-bit Power Accumulator Register for Recording

Accumulated Power Data

◦ 32-bit Accumulator Count Register

The availability of C-based software at https://ww1.microchip.com/downloads/aemDocuments/documents/MSLD/ProductDocuments/SoftwareLibraries/Firmware/pac1711-genlib-c-package.zip furthermore simplifies data collection. Designers can use these libraries with a variety of embedded software systems to streamline data collection. Alternatively, the data sheet can be studied to reveal design communication structograms, such as the one shown in the figure below. These can then be used to create custom drivers.

Housing Options and Development Kit for Design Bring-Up

Evaluating the product family is simplified by the availability of two MikroElektronika click boards. Orderable under SKUs MIKROE-6801 and MIKROE-6862, they present as shown in the figure below.

As for SKUs, Microchip provides both eight- and ten-pin variants across the family. Both use the VDFN case, with some versions being pin-compatible with eight-pin SOT23 housings. The eight-pin, 12-bit version can be ordered under SKU PAC1711T-1E/3P, while the 10-pin version is orderable under SKU PAC1711T-2E/9Q. For the PAC1811, SKUs PAC1811T-2E/9QVAO and PAC1811T-1E/3PVAO are automotive qualified, while PAC1811T-2E/9Q and PAC1811T-1E/3P are non-automotive.

Conclusion

Microchip's PAC1x11 family greatly simplifies power consumption measurements. If a current shunt needs monitoring, the low quiescent current and the high accuracy deserve attention.