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Subsystem power measurement of your embedded device

Subsystem power measurement of your embedded device

Set up for subsystem measurement with Otii

Power profile subsystem with Otii

Subsystem power measurements, alongside total DUT power consumption, provide clearer insight into energy consumption and efficiency.

By measuring the power usage of individual subsystems on the DUT, you can better understand how energy flows within the device and identify which components consume the most power. This allows you to focus development efforts where they will have the greatest impact on energy efficiency and battery life.

This setup works seamlessly with the Otii Arc and Otii Ace, enabling precise, dual-channel power profiling.

For example, the main channel can power and measure the entire DUT – tracking current, power, and energy from the battery – while a secondary channel monitors a specific subsystem, such as the radio or sensor module. 

Products needed

Otii Ace Pro  or  Otii Arc Pro

Otii Ace measuring subsystem power.
How to connect power profiling and subsystem power measurements with Otii Arc and Ace.

How to connect

  1. Connect Arc/Ace to your computer by USB. If needed, add a power supply via power outlet.
  2. Connect Arc/Ace’s banana connector + to DUT positive battery connector/power connector.
  3. Connect Arc/Ace’s banana connector – to DUT negative battery connector/power connector GND
  4. Connect an external shunt resistor (R) in series with the sub-system power rail. The value of the shunt resistor must be calculated so the voltage drop over it is less than Arc/Ace data sheet value for differential voltage measurement (Arc +- 81.2 mV, Ace +-102.4 mV).
  5. Connect ADC+ to the high side of the shunt resistor; this will also be the voltage measurement point for the sub-system.
  6. Connect ADC- to the low side of the shunt resistor.
  7. Connect AGND to DUT GND

Get started in the Otii app

  1. Add your Arc/Ace under Control in the sidebar. Rename it if desired (right-click).
  2. Set up the voltage you want to supply your DUT with under Arc/Ace. The power box will be chosen by default. Add OC protection for your DUT.
  3. Enter the shunt resistor value (R) in ‘ADC resistor’
  4. Under ‘Channels’, choose the measurements you want to record, for example, main current, main voltage, and main power, as well as ADC current, ADC voltage, and ADC power channel for subsystem power measurement. These will show as graphs.
  5. Start a recording. Your DUT is still not powered; you will only see measured noise.
  6. Power the DUT by turning on the supply (On button) next to the Arc/Ace. The data from your DUT is now being recorded.