Ultra Low Power MCU – How to measure energy consumption?

Starting with ULP MCUs like Ambiq Micros Apollo1 or Apollo2 available via shop.feeu.com is very easy, but designing ULP applications can be a nightmare without good tools measuring the power consumption. For Ambiq Micro Apollo Series MCUs Fujitsu Electronics Europe GmbH realized different possibilities to measure ultra low power consumption.

On the one hand FEEU is offering breakout boards for Apollo1 and Apollo2 for having as less components as possible. So no fancy circuits on an EVK you can’t really trust, just the RAW MCU with the passives. Btw. avaulable in FEEUs webshop:

On the other hand FEEU is offering an Arduino form factor baseboard for their breakout boards with on-board debugger able to do ultra low power measurement: shop.feeu.com/Shops/es966226/Products/SK-AMAPOLLO-BASE-V11

The SK-APOLLO-BASE tool is low-cost and helps to get a rough number about the applications power consumption. For the beginning a good reference! As soon it have to be professional tools, there is the need for a professional ULP multimeter and a professional ULP debug probe. A multimeter is normally calibrated and give a reference value you can trust. A professional debug probe with ultra low power measurement and is doing the linkage between energy consumption and code is a big plus for easily finding energy hungry code execution and in my eyes an absolutely must for ULP developers.

So comparing 3 different ULP tools for the first start (more on ULP debug probes in the next posts):

  • Fujitsu Electronics Europe GmbH SK-APOLLO-BASE
  • ARMKeil ULINKplus
  • Gossen Metrawatt METRAHIT ULTRA

All tools reporting in a Digital Multimeter Mode for a test application ~360µA.


Available at: shop.feeu.com/Shops/es966226/Products/SK-AMAPOLLO-BASE-V11

Breakout board for Apollo1: shop.feeu.com/Shops/es966226/Products/SK-AMAP1-BREAKOUT-V11

Breakout board for Apollo2: shop.feeu.com/Shops/es966226/Products/SK-AMAP2-BREAKOUT-V11

Documentation at: http://www.fujitsu.com/uk/products/devices/semiconductor/ulp-mcus-rtcs/products/ulp-mcu/evaluation-kits/evalplatform/

SK-APOLLO-BASE is more or less a integrated evaluation kit solution and the on-board debugger can report via USB with a digital multimeter application voltage and current. The measurement resolution and time-resolution is ok. ULP power measurement is available via CMSIS-DAP protocol. It is with around 60$ the cheapest solution but with limited support.


See more: www.keil.com/ulinkplus

ARMKeil ULINKplus is the all-in-one ULP solution giving possibility to match running code and trace data with the current / voltage consumption and calulates the power. The measurement resolution and time-resolution is awesome! With around 700$ it is a professional tool usable for debug, trace, test-environment and power measurement. A must for every embedded systems developer!


See more: www.gossenmetrawatt.com/english/produkte/metrahitultra.htm

METRAHIT ULTRA is a ULP digital voltmeter able to measure down to nano amps. With around 800$ it is a upper-range digital multimeter but one of the only true ULP digital multimeters.

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