Power Consumption AnalysisFollow article
The world is getting more and more connected. Myriads of sensors and IoT applications factories and households, enabling optimal industrial operation and contributing to improvement of the social welfare.
Maximizing battery lifetime
Many of these products run on very small non-rechargeable batteries at low voltages and currents. Battery-powered devices can be easily installed anywhere and are small, robust and easy to use. High replacement costs and environmental concerns demand for long operating times. Battery lifetime is a key aspect for the design and selection of IoT devices. Depending on the application and use cases, absolute battery life requirements can range from tens of hours for wearables such as smart watches, to tens of years for smart meters and environmental sensors. What all these applications have in common is the need to maximize battery life.
IoT test challenges
In order to meet the application requirements, power consumption characteristics need to be optimized at the product design stage. This requires accurately characterizing the device’s power consumption in different operating modes, which is not an easy task. Modeling and dimensioning the energy consumption of an application at the design stage is of utmost importance considering the critical requirements for IoT applications: reduced cost, lifetime, improved customer experience and regulatory requirements.
Designing appropriate hardware and software is key for low-power devices, e.g. implementing optimal power consumption in active and deep sleep modes or short startup/shutdown phases. It needs to be considered that power consumption often has a high dynamic range with fast switching between operational modes in the tens or hundreds of mill amperes and sleep modes measured in microamperes. Power consumption also strongly depends on the use of power saving features, application behavior and interaction with the wireless network.
Device and application developers require very accurate power measurement solutions with a high dynamic range. Rohde & Schwarz offers modern solutions such as the R&S®NGL200 power supply or the R&S®NGM200 power supply series that are an easy and economical solution for these measurements and offer an outstanding resolution. Both instruments provide advanced features and meet the requirements for high-precision power consumption measuring capabilities. The R&S®NGM200 series even provides resolutions down to 5 μV/10 nA, allowing accurate measurements that easily match the requirements of today’s standards used in IoT devices.
The FastLog functionality
For in-depth analysis and traceable results, the measurement values can be logged. When opening the logging settings, you can choose the desired preferences. With a user-defined acquisition rate of up to 500 ksample/s, the FastLog functionality follows voltage/current variations with a resolution of up to two μs. It detects spikes that would be overseen by slower instruments.
The logged data can be stored on the power supply’s internal memory or on an external USB storage device. The data can then be transferred to an external PC via USB or LAN. For automated and long-term tests, Rohde & Schwarz provides a remote control software. Parameters like power consumption, current drain or battery capacity can be easily determined and analyzed. The tool also offers a graphical representation of logged data with zoom function.
If you aim for high-quality results, you may use specialty DC power supplies from Rohde & Schwarz that meet the requirements for high-precision power consumption measurements such as theR&S®HM8143. They measure a wide dynamic range of current levels and are highly accurate even at extremely low voltage and current levels. Their linear design with minimum residual ripple and noise, and advanced remote monitoring features make the instruments an excellent choice for optimizing power consumption in IoT devices.