The Nordic Semiconductor nPM1100 PMIC | Hackster Spotlight

The wonders of low-power

With the recent proliferation of wearables and other small, battery-powered internet of things (IoT) devices, limiting how much current they draw is vital for extending their battery life and usable time. This is achieved by using higher efficiency parts in conjunction with certain power saving techniques.

What is the nPM1100?

Portable devices all rely on batteries, typically a small lithium polymer (LiPo) cell which fits into their enclosures. These need charging and power regulation. Charging is managed by charge controller that charges the battery according to its specification and switches power delivery to the system from USB to battery when the charge cable is unplugged. The system also needs a power regulator that regulates the voltage from the typical 3.5-4.2V down to a fixed voltage within the operating range of the application. However, these often take up a lot of real-estate on PCBs and can add extra costs, which is why Nordic Semiconductor has released their nPM1100 power management IC (PMIC). It is a small 2x2mm chip that combines both a buck regulator and integrated battery charger. Best of all, the IC and its external passive components can be placed into an area as small as 23mm².

Versatility is everything

The primary goal with the nPM1100 was to create a tiny power management IC that can be placed into a wide range of small, portable devices. As such, it has an amazing set of features. These include

• USB compatibility and automatic port detection for battery charging
• Selectable charging currents between 20 and 400mA
• Automatic selection between trickle, constant current, and constant voltage charging modes with thermal protection
• A step-down buck regulator with a maximum output of 150mA at 1.8, 2.1, 2.7, or 3v
• A power conversion efficiency of up to 92% for smaller batteries or a longer "on time" per charge

Possible applications

The nPM1100 PMIC was designed to complement Nordic Semiconductor's lineup of nRF52 Series and nRF53 Series SoCs, although it can also be used generically too in many other circuits.

Imagine a Bluetooth Low Energy device with the nRF5340 system on a chip that acts as a warehouse tracking beacon, or a wearable fitness device that can go for days without needing to be charged. By integrating the nPM1100, small devices can be both charged and efficiently powered without the need for a lot of external components that consume valuable PCB real estate, making more space for larger batteries.

Going further

To get started with the nPM1100 from Nordic Semiconductor, you can visit its product page or check out their evaluation kit which contains the IC along with two sets of breakout pins, a USB port, and a LiPo battery connector for easy experimentation. There is even a header for attaching the Nordic Semiconductor Power Profiler Kit II and a development kit of your choice to quickly measure the power draw.