The use of health and fitness trackers, body sensors, other small electronic wearables and implants, as well as wireless monitoring devices is increasing. However, the need for batteries and external energy sources to power these devices is a severe constraint for overall product design, practical usage, and maintenance – especially in remote areas.
By actively utilising available thermal energy it is possible to open up new application fields and design options. However, a DC-DC converter is required to boost the harvested voltage and effectively use the resulting output to power small electronic devices, omitting the need for primary batteries.
AKM’s AP4473 is a DC-DC step-up converter that can boost an input voltage of as low as 15 millivolts (mV) while maintaining an ultra-low power consumption of only 26 nanoamperes (nA).
This single-chip solution allows electricity generation from a minimal thermal energy source, such as body heat, while enabling overcharge prevention and power supply control with minimal energy consumption.
In addition to the boost circuit, the device incorporates a PMOS switch and two hysteresis comparators. The switch disconnects the energy storage devices, such as capacitors, from the system, while its comparators automatically start and stop supplying power to the system. This makes it possible to configure a power supply unit in an energy harvesting system with a minimal number of passive elements, contributing to size and cost reductions for the overall system.
The AP4473 is suitable for applications in beacons for asset tracking and asset monitoring, environmental monitoring and IoT sensor nodes, as well as smartcards or IoT devices.
