New Industry Products

Ultra-Low Power PMIC for Thermally-Based Energy Harvesting

February 27, 2019 by Paul Shepard

A new power management IC capable of 100mV cold start, with extended input voltage range is now available from e-peas. This PMIC has been specifically optimized for energy harvesting from thermal sources in wireless sensors application.

Supplied in a space-saving 28-pin QFN package, the AEM20940 is a highly advanced device based on proprietary technology that is capable of extracting available input current up to levels of 110mA. Pictured above is the AEM20940 on its evaluation board.

Taking dc power from a connected thermal electric generator (TEG), it can supervise the storing of energy in a rechargeable element and simultaneously supply energy to the system via 2 different regulated voltages. This is done through its built-in low noise, high stability 1.2/1.8V and 2.5/3.3V LDO voltage regulators. The lower voltage can be employed for driving the system microcontroller, while the higher voltage is intended for the RF transceiver.

Through the AEM20940's deployment, it will be possible to extend the system battery life or, in many cases, eliminate the primary power source from the system completely. By this any dependence on having to regularly replace batteries (which often has serious logistical challenges associated with it, as well as adding to the overall expense) can be removed.

A key characteristic of the device is its ultra-low power start-up characteristics. It can achieve a cold start (with no stored energy available) from just a 100mV input voltage and 80μW input power with an external module. Sophisticated energy management functions enable fast supercapacitor charging and warn when stored energy reserves are running low.

"Having a thermal energy harvesting solution to add to our portfolio is a significant step forward for the company, as we look to establish ourselves as the leading IC manufacturer in the rapidly maturing energy harvesting sector, offering the most complete and innovative PMIC products," explains Geoffroy Gosset, co-founder and CEO of e-peas.

"It means that our clients will be able to design IoT systems that can efficiently extract energy from their surrounding environment whatever the available sources," Gosset concluded.

Summary of features

  • Ultra-low-power start-up
    • Cold start from 100 mV input voltage and 80 µW input power (typical)
  • Ultra-low-power Boost regulator
    • Configurable MPPT with 2-pin programming
    • Selectable Voc ratios of 50, 55 or 75%
    • Open circuit voltage sensing for MPPT every 21 s
    • Input voltage operation range from 50 mV to 5 V
  • Integrated LDO regulator at low voltage
    • 2/1.8 V, high efficiency
    • Up to 20 mA load current
    • Power gated by external control
  • Integrated LDO regulator at high voltage
    • Configurable : 1.8-2.5-3.3 V
    • Up to 80 mA load current with 300 mV drop-out
    • Power gated by external control
  • Flexible energy storage management
    • Programmable overcharge and overdischarge protection
    • For any type of rechargeable battery or (super)capacitor
    • Fast supercapacitor charging
    • Warns load when battery is running low
    • Warns when output voltage regulators are available
  • Optional primary battery
    • Automatically switches to the primary battery when secondary battery is exhausted

The main target applications envisaged for the AEM20940 are in industrial process monitoring, HVAC and predictive maintenance.