The Challenge of Measuring Low IoT Currents

To maximize battery life, your product current draw must be kept to an absolute minimum. This requires that you use low power components and efficient techniques to de-energize components when they are not in use. You need sensitive measurement instrumentation to measure current levels as low as nA.

 

Determine the load current profile

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

Determine the Average Current of an IoT Device

Measuring Ultra-Low Power in Wireless Sensor Nodes

 

Simulate any battery type

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.

How the 2281-S Emulates a battery

 

Model any type of battery

 

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.

How to create a battery discharge model

 

 

Featured Content

 

Power Consumption Profiling and Battery Life Analysis Techniques	Determining the Average Current of an IoT Device	Measuring Ultra-Low Power in Wireless Sensor Nodes
Fact Sheet	Video	Application Note
Learn about the latest test solutions for evaluating battery life in portable, low-power devices.	This video shows how a graphical sampling digital multimeter can capture the current drain in all states of an IoT product from the low power sleep mode to the full power transmit mode, load current burst.	This application note provides information on how to characterize the power consumption of a wireless sensor node.

 

 

Determine Load Current Profile	Simulate Any Battery	Model Any Type of Battery
DMM7510	2281S	2450 and 2460 SMU Instruments
The DMM7510 delivers a wide current measurement range, picoamp current sensitivity, high speed sampling, and a 27 million reading memory buffer to measure and store a prototype device’s current profile.	Model any type of battery required to test devices efficiently and repeatably at any battery state. Also ideal for estimating battery life effectively is the combinination of a 2281S-20-6 with a DMM7510 to provide a complete solution for power consumption/battery life assessment.	These SMU instruments can operate as a sensitive, electronic load to discharge a battery. In adddition, the SMUs can execute test scripts to monitor battery drain and create a model-generating script that lets them operate as a constant current load and derive the model parameters.
1 Msamples/s current digitizer 100 pA – 10 A measurement range 27 million reading storage µA current triggering Touchscreen with graphical display	20 V, 6 A, 120 W capacity Simulates battery output using dynamic models Displays, Voc, SOC, Amp-Hr, and internal resistance Display visualization of battery state x	Constant voltage or constant current sourcing or sinking (four-quadrant operation) Up to 200 V, 7 A, 200 W Battery model application

 

 

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