The AEM40940 is an integrated energy management subsystem that extracts AC power from high-frequency RF inputs to simultaneously store energy in a rechargeable element and supply the system with two independent regulated voltages.
The AEM40940 allows to extend battery lifetime and ultimately eliminates the primary energy storage element in a large range of wireless applications, such as industrial monitoring, indoor geolocation, home automation, e-health monitoring and wireless sensor nodes. The AEM40940 harvests the available input power up to 10 dBm. It integrates an ultra-low power rectifier combined with a boost converter to charge a storage element, such as a Li-ion battery, a thin film battery, a supercapacitor or a conventional capacitor.
With its unique cold-start circuit, it can start operating with empty storage elements at an input power as low as -19.5 dBm.
The low-voltage supply typically drives a microcontroller at 1.2 V or 1.8 V. The high-voltage supply typically drives a radio transceiver at 1.8 V, 2.5 V or 3.3 V. Both are driven by highlyefficient LDO (Low Drop-Out) regulators for low noise and high stability.
Configuration pins determine various operating modes by setting predefined conditions for the energy storage element (overcharge or overdischarge voltages), and by selecting the voltage of the high-voltage supply and the low-voltage supply. The chip integrates all the active elements for powering a typical wireless sensor.
Five capacitors and two inductors are required, available in the small 0402 and 0603 size, respectively. With only seven external components excluding the matching network, integration is maximum, footprint and BOM are minimum, optimizing the time-to-market and the costs of WSN designs.