RF Wireless World

Browse articles, tutorials, tools, and vendors.

Next-Gen Power Management for Complex IoT Devices

By RF Wireless Expert Team

Introduction : In the early days of the Internet of Things, devices were relatively simple. A basic Bluetooth tag or temperature sensor had a single microcontroller and a single sensor, running off a coin cell battery for years.

Today, edge devices are incredibly complex. A modern smart home hub or wearable device might include a dual core processor running Machine Learning algorithms, a Wi-Fi 6 radio for cloud communication, a Bluetooth LE radio for local pairing and an array of environmental and motion sensors.

Each of these components requires a different voltage to operate efficiently. If a hardware engineer uses traditional, inefficient voltage regulators to step down the battery power for each chip, the device will drain its battery in a matter of days. Furthermore, individual regulators take up valuable space on the printed circuit board (PCB).

To solve this, hardware engineers are turning to Next-Gen Power Management ICs (PMICs) to act as the “brain” of the device’s power architecture.

What is an Advanced PMIC?

A PMIC is a dedicated microchip designed entirely to manage, distribute and monitor power across a circuit board. Instead of slapping multiple discrete regulators onto a board, engineers use a single, highly integrated PMIC (such as Nordic Semiconductor’s newly introduced nPM6001) to handle the entire system’s power needs.

The true superpower of a next-gen PMIC lies in its ability to manage independent power domains (also known as power rails).

Maximizing Battery Life via Independent Power Domains

A complex IoT device is partitioned into different domains. For example, the Wi-Fi chip is one domain, the Bluetooth System on Chip (SoC) is another and the microphone array is a third.

An advanced PMIC features multiple, independently controlled power rails tailored to these domains. (The nPM6001, for instance, features six distinct rails). Here is how independent control maximizes battery life.

1. Surgical Power Gating (Shutting off Vampire Draw)

In older designs, putting a device to “sleep” meant putting the processor into a low power state, but the physical power lines to the sensors or Wi-Fi chips might still leak current. With an advanced PMIC, the main processor can instruct the PMIC to completely sever the power supply to specific domains. If the IoT device doesn’t need to connect to the cloud for the next hour, the PMIC turns off the Wi-Fi 6 power rail entirely, while keeping the ultra-low power Bluetooth LE rail active to listen for local commands.

2. Mixing Buck Regulators and LDOs

Not all components need the same type of power. Next-gen PMICs combine different types of regulators into one package:

  • Step-Down (Buck) Regulators: These are highly efficient at dropping a battery’s voltage down to the level needed by heavy lifting chips (like main processors and radios).
  • Low Dropout (LDO) Regulators: While slightly less efficient, LDOs provide exceptionally clean and stable power. PMICs use independent LDO rails to supply power to sensitive analog sensors (like audio microphones or biometric heart rate sensors) where electrical noise from a buck regulator would ruin the sensor readings.

3. Deep Hibernate Modes and Hardware Watchdogs

Advanced PMICs are designed to push energy conservation to the absolute limit. They incorporate Watchdog Timers (WDT). A WDT is a hardware timer that continuously counts down; if the main IoT processor doesn’t periodically “pet” the watchdog (reset the timer) because it crashed or went to sleep, the PMIC takes action.

Using this timer, a PMIC can enter a “Hibernate Mode.” It shuts down power to the entire circuit board including the main processors leaving only a tiny 2 kHz oscillator running. In this state, the PMIC consumes an astonishingly low (~ 200 nanoamps). When the timer expires, the PMIC wakes the system back up to take a sensor reading.

4. Dynamic Dual Mode Regulation

Battery load in an IoT device fluctuates wildly. When transmitting Wi-Fi, the device pulls a massive surge of current. When sleeping, it pulls almost nothing. Advanced companion PMICs (like the nPM1100 battery charging IC) feature dual mode regulation. They automatically switch between PWM mode (Pulse Width Modulation) for clean, high performance power during heavy data transmission and Hysteretic mode during sleep phases to drastically reduce the regulator’s own current consumption.

Conclusion

By consolidating battery charging, voltage regulation and independent power rail control into a single chip footprint (often as small as 2x2 millimeters), PMICs allow developers to build smarter, smaller and vastly more complex edge devices without sacrificing the multi-year battery life that consumers expect.

Continue Learning PMIC

Continue Learning IoT Basics, Architecture & Tutorials

Hardware: IoT Sensors, Actuators & SoCs

Real-World IoT Applications & Systems

Keep Reading

Related Posts