Mr. Sambit Sengupta | Associate Director – Field Applications | Avnet India
In our increasing connected world, technology and smart devices are transforming the way we live. The most visible applications around us are smart and connected consumer products. Powered mostly by small batteries such as button or coin cell types, these products range from smart watches, fitness trackers, heart-rate monitors, sports equipment to a variety of other wearable devices. The key parameters that product designers consider in such applications are long battery life and very low power consumption. Power management ICs (PMICs) provide multiple voltage rails and efficient battery management capabilities which help to extend battery life in consumer IoT applications. Applications for wearable or connected devices being very small form factor, need precise but simple low-power monitoring circuits. These PMICs need to assess the health and state of charge of these batteries but they themselves need to be ultra-low power consumption devices.
There is wide availability of fuel gauge ICs with built in security which deliver precise current, voltage and temperature measurements. Reputable semiconductor companies such as Maxim Integrated, Power Integrations, STMicroelectronics, Dialog Semiconductor offer safe and efficient power management in very small form factor to support IoT devices, powered by rechargeable, high energy densified Li-ion batteries.
The connected devices of today are targeted at mass market, which must strike a balance between price and utility. The power management needs to be optimum and hence we will like to see the available options as of today.
MAX77650/ MAX77651 offer a highly integrated battery charging and power supply solution for low power wearable applications. These feature a buck-boost regulator that provides three independently programmable power rails from a single inductor to minimize total solution size. The 150mA LDO provides ripple rejection for audio and other noise sensitive applications. Hardware designers now have multiple options to get off-the-shelf power management solutions from semiconductor OEMs. Apart from reaching out to semiconductor distributers like Avnet or element14, they may also refer to various useful online resources.
As battery-powered IoT products continue to evolve in features, performance and decreasing in size, their power consumption has increased significantly. Therefore, power management has become of paramount importance in order to maximize battery life, prolong product operation and reduce heat dissipation. Performance improvement of low voltage DC-DC converters has received a lot of attention and presently efficiencies higher than 94% have been realized. If you are designing wall sockets or smart sockets, smart switch with Wi-Fi, or smart speakers, you can consider products such as InnoSwitch3-Pro or InnoSwitch3-CP.
Often designers have to consider the power consumption of the connectivity that they plan to use. To give you an understanding, let us consider the below diagram which summarizes the power consumption for various standards as of today.
As shown in the diagram, a single power management solution may not be suitable for every device. For example, for someone using LoRa cost-optimized module from Murata or making their own LPWAN module, they may consider STBC02, a highly cost-optimized Li-ion battery charger solution. Below is a good example of an evaluation circuit which uses STUSB1600A, STBC02 and a step down converter.
There are various options available for designers. Choosing the optimum power management IC for your connected device ultimately depends on the application, the requirements and the modules used. Alternatively, joining an online IoT community also allows designers to learn from a wider community.