Sensors have become a pillar of modern technology, integral to nearly every device and present across every sector. While traditional analog sensors were often large, power-hungry devices, modern digital sensors are now so ubiquitous in devices, they are often some of the smallest, most efficient components, and typically low-power. Let's explore the most popular low-power and ultra-low power sensors on the market and examine their most common applications.
Low-Power current sensors
Current sensing can be a valuable tool for determining the overall health of a lower power circuit, and the overall energy consumption of a system. Sensing can also aid with minimizing a low-power device's power consumption. In applications requiring ultra-low power consumption, utilizing a current sensor that consumes low power itself can be essential. There are several methods for current sensing, depending on the application, voltage, and currents measured.
For ultra-lower power applications, such as battery-powered remote IoT devices, we recommend implementing low-side current sensing methods. This application often utilizes specifically-designed current-sensing amplifiers -- for example, TI’s INA199 amplifier. This special-purpose amplifier is specifically designed for current sensing applications, since it has extremely low error when compared to similar capability op amps. If you’d like to learn more about low-side current sensing, reference our article What is Low-Side Current Sensing?
Low-Power radar sensors
Radar has evolved significantly since it was first introduced in the 1930s. In fact, it has evolved greatly over the last 10 years alone. With the increase in microcontroller integration and specialization in radar applications, radar modules are becoming increasingly more accurate and low-power. A fantastic example of a low-power radar sensor is Infineon’s BGT24LTR11. This sensor operates using 24Ghz radar technology. It's currently the smallest 24Ghz MMIC in the market. Low-power radar sensors such as these are still sufficient for applications like doppler-based direction of movement detection, speed estimation, and distance measurement to objects. To learn more about this Infineon product specifically, or its DEMO SENSE2GOL sister development board, be sure to read up on Intelligent Sensors using 24GHz Radar Technology.
Low-Power hall-effect sensors
Hall-effect sensors are a fantastic tool for electrical engineers; they can be used in a variety of applications, such as control circuits, or switching circuits when mechanical switches cannot be used due to environmental conditions. Since hall-effect sensors detect magnetic fields, they can be shrouded and protected from harmful environmental factors, whereas a mechanical switch cannot be. Unfortunately, hall-effect sensors do require energy to operate, and this can make them undesirable for applications where ultra-low power consumption is required. However, several Hall-effect sensors can achieve ultra-low power consumption during operation.
The hall-effect sensors in TI’s DRV Series, for example, are all capable of ultra-low power consumption. This series also boasts a variety of different magnetic types, including bipolar, bipolar latch, omnipolar, ratiometric, and unipolar. The DRV series has been optimized for industrial and automotive use, making the sensors extremely durable in IoT applications. These sensors even boast varying levels of minimum magnetic sensor release sensitivity, ranging from -180Gs to 300Gs. For more information on industrial and automotive hall-effect sensors, be sure to read this article.
Low-Power temperature sensors
Temperature sensors have become an essential component in nearly every electrical device in the IoT sector, as well as the industrial, automotive, agricultural, and even residential sectors. The versatility and reliability of modern temperature sensors expands far beyond the capabilities of traditional analog sensors. They can also be wildly accurate. In many applications, however, such as remote IoT Smart Agriculture, power consumption and reliability of the temperature sensor are paramount to ensure the product remains operable for a desired amount of time, while still maintaining its effectiveness. STMicroelectronics offers an ultra-low power temperature sensor via their STLM20 Series. This series provides an operating voltage of 2.4 to 5.5V, with a typical maximum supply voltage of 4.8 and 8.0 uA. It provides a typical temperature accuracy of +/- 0.5 degC. Low power temperature sensors are ideal for smartphones, portable IoT devices, and even RF monitoring devices.
BONUS: combined magnetic and temperature sensor
If you're looking for ultra-low power consumption from both a magnetic (hall-effect) sensor and a temperature sensor, consider utilizing Infineon’s 3D magnetic Sensor TVL493D. Additionally, our article 3D Magnetic Sensor with Ultra-Low Power showcases the capabilities of this sensor, as well as applications in which it can reduce parts count and system power consumption.
Low-Power IR sensor
Low-power infrared sensors are most often used in proximity detection systems. Unfortunately, most IR sensors demand the use of both an emitter and a receiver, and this can drastically influence the power consumption of a sensor. While this makes it challenging for low-power IR sensors to achieve long-range proximity sensing, they do excel at short range proximity sensing, up to ~50cm. The Si1102, from Silicon Labs, for example, is a high-performance, single pulse IR sensor that achieves ultra-low power consumption. The Si1102 is extremely versatile; it can be implemented in any application where 2-5.5V is available, while still consuming less than 10 uA of current.
Conclusion: a diverse range of low power sensor types
As remote electronics and battery-powered IoT devices have made their way into nearly every sector, low-energy sensors have gained significant popularity. This increase in popularity has brought a massive wave of innovation for a variety of sensor types, therefore optimizing power consumption, accuracy, and cost effectiveness. For more information on sensors of all varieties be sure to shop Arrow.com.
