e-peas AEM30940 RF Energy Harvesting IC

e-peas AEM30940 RF Energy Harvesting IC is an integrated energy management circuit that extracts DC power from a piezo generator, a microturbine generator, or any high-frequency RF input to simultaneously store energy in a rechargeable element and supply the system with two independent regulated voltages. The AEM30940 extends the battery lifetime and ultimately eliminates the primary energy storage element in a large range of wireless applications such as industrial monitoring, home automation, transportation, and smart agriculture.

The AEM30940 harvests the available input current up to 110mA while regulating the source to a voltage configured by the user. 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 ranging from 50mV to 5V. With its unique cold-start circuit, the device can start operating with empty storage elements at an input voltage as low as 380mV and an input power of only 3µW.

The low-voltage supply typically drives a microcontroller at 1.2V or 1.8V, and the high-voltage supply typically drives a radio transceiver at a configurable voltage between 1.8V and 4.1V. Both are driven by highly efficient LDO (Low Drop-Out) linear regulators for low noise and high stability.

Configuration pins determine various operating modes by setting predefined conditions for the energy storage element (overcharge or over-discharge voltages) and by selecting the voltage of the high-voltage supply and the low-voltage supply. Special modes can be obtained at the expense of a few configuration resistors.

The chip integrates all active elements to power a typical wireless sensor. Five capacitors and two inductors are required, all available in small packages. With only seven external components, integration is maximized, and the footprint and BOM are minimized, optimizing the time-to-market and costs of designs.

Features

Ultra-low-power start-up, cold start from 380mV input voltage and 3μW input power (typical)
Ultra-low-power boost regulator
- Open-circuit voltage sensing for MPPT every 0.33s
- Configurable MPPT with 2-pin programming
- Selectable V_OC ratios of 50%, 65%, or 80%
- 50mV to 5V harvesting input voltage operation range
- 50mV to 5V MPPT voltage operation range
- Constant impedance matching (ZMPPT)
Integrated 1.2V/1.8V LDO regulator
- Up to 20mA load current
- Dynamically power gated by an external control
- Selectable output voltage
Integrated 1.8V to 4.1V LDO regulator
- Up to 80mA load current with 300mV drop-out
- Dynamically power gated by an external control
- Selectable or adjustable output voltage

Flexible energy storage management
- Selectable or adjustable overcharge and over-discharge protection for any type of rechargeable battery or supercapacitor
- Fast supercapacitor charging
- Indication when the battery is running low
- Indication when output voltage regulators are available
Optional primary battery, automatic switching to the primary battery when the secondary battery is exhausted
Integrated storage element balancing circuit for dual-cell supercapacitor
Small footprint, small BOM
- Compact 5mm x 5mm QFN28 package
- Only seven passive external components required