The Challenge of Measuring Low IoT Currents

It can be difficult to characterize the load current profile of a prototype IoT device, because you must measure the current in a wide range of operating states:

• sleep mode (from nA to µA),
• standby modes (from hundreds of microamps to tens of milliamps), and
• active states (from milliamps to amps), including short current bursts due to wireless transmissions

To accurately capture these widely varying load current levels, you need an exceptional measurement solution that includes:

• A wide current measurement range, from hundreds of nanoamps to amps
• The measurement speed to capture current pulses just a few microseconds wide
• A large memory buffer to store the prototype device’s current profile

Keithley’s DMM7510 7½-digit Graphical Sampling Multimeter is well-equipped to meet these demands, as it offers:

• pA current sensitivity
• 1 Msample/s sampling
• 27 M data points of memory

How low can the battery voltage drop before your IoT device turns off? Gauging battery performance at different stages of battery discharge is difficult, as it requires instrumentation that can accurately simulate battery performance.

To address this, Keithley’s 2281S-20-6 Battery Simulator makes it easy to model any type of battery. It allows you to efficiently test prototype IoT devices in any battery state, with high repeatability to effectively estimate battery life. Combining a 2281S-20-6 Battery Simulator with a DMM7510 Graphical Sampling Multimeter will give you a complete solution for assessing power consumption and battery life of your IoT prototypes.

The final piece of the puzzle is to create a model for the battery that powers your IoT device. Keithley’s 2450 or 2460 Graphical SourceMeter® Source Measure Unit (SMU) instruments make it easy to create the model for the battery used by your product.

A battery model-generating script operates the SMU instrument as a controlled current load and derives the model parameters.