The AEM20940 is an integrated energy management subsystem that extracts DC power from a TEG to simultaneously store energy in a rechargeable element and supply the system with two independent regulated voltages.
The AEM20940 allows to extend battery lifetime and ultimately eliminates the primary energy storage element in a large range of wireless applications like industrial monitoring, home automation and smart agriculture. The AEM20940 harvests the available input current up to 110 mA. It integrates an ultra-low power boost converter to charge a storage element, such as a Li-ion battery, a thin film battery, a supercapacitor or a conventional capacitor. The boost converter operates with input voltages in a range from 50 mV to 5 V.
With its unique cold-start circuit, it can start operating with empty storage elements at an input voltage as low as 380 mVand an input power of just 100 µW.Thanks to an external optional module, the input voltage for coldstart lowers to 60 mV with an input power of just 150 µW.
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, integration is maximum, footprint and BOM are minimum, optimizing the timeto-market and the costs of WSN designs.