We have completed the Experimenting with Current Sense Amplifiers Design Challenge, sponsored by Maxim Integrated - ADI, and featuring its MAX40080 Precision, Fast Sample-Rate, Digital Current-Sense Amplifier. Overall, we had 10 participants with 9 finishers, including our Grand and Runner Up Prize winners. Our judges have read all the blogs and made their decisions. In this blog we will announce the winners.
First Things: Let's Talk About Current Sense Amplifiers
The need is growing for fast and accurate current sensing for overcurrent (fault) protection, current metering, power monitoring, and battery management/monitoring. Current sense amplifiers (CSAs) are designed to perform these important functions. A current sense amplifier (also called a current shunt amplifier) is a purpose-built, differential amplifier IC that's designed to sense the voltage developed across a current shunt resistor and produce a voltage proportional to the measured current. Today's current sense amplifiers are high-precision, bi-directional devices with digital outputs, fast sampling rates, and very wide input common-mode range.
How Does the MAX40080 Current Sense Amplifier Work
The MAX40080 is a high-precision, fast-response, bi-directional current-sense amplifier with digital output and a very wide input common-mode range from -0.1V (ground sensing) to 36V. The device features an ultra-low 5μV input offset voltage and a very low 0.2% gain error. The low input offset voltage is especially important because it allows the use of a small sense resistor, thus saving power dissipation, but at the same time not compromising the measurement accuracy. The device also features a programmable input sensing range between ±10mV and ±50mV (or programmable input gain between 125V/V and 25V/V) which is very useful to enhance accuracy at low current.
The device includes an analog-to-digital converter with a programmable sample rate and 12-bit resolution (13-bit including sign bit for current measurement) and features an I2C compliant and SMBus compatible interface. It features a wake-up current threshold and auto-shutdown mode when the I2C is inactive. Both of these features are designed to minimize power consumption. It is available in a small 12-pin WLP (and also a 12-pin TDFN) and is specified over the -40°C to +125°C extended operating temperature range.
element14's Experimenting with Current Sense Amplifiers competition was an opportunity to provide our participants with a kit of Maxim's MAX40080 so that they could conduct experiments and blog about what they learned.
Grand Prize Winner: Michal Zurek (misaz)
Misaz did a huge body of work which resulted in not only a lot of content, a total of 14 blogs, but also a good amount of interaction with members interested in what work he produced. As judge Doug Wong stated, "His applications had wide appeal and the scope of his work was extensive, including both PCB design and software driver library development."
He planned to do four experiments:
- Initial simple experiment: Measuring current flowing by resistor, converting value returned by sensor and writing library.
- Raspberry Pi self-power consumption monitoring
- USB Type-C PD Current and Voltage monitoring
- Power consumption logging and electricity cost estimation
In blog 2, he wrote a mini-tutorial showing basic usage of MAX40080 CSA and the related Current 6 Click board with Raspberry Pi. In blog 3, he continued with fundamentals of MAX40080 CSA and described approaches for converting measured digital value in range between -4095 and 4095 to real value in Ampere units. In blog 4, he introduced his experimental set up for developing and debugging his own library targeting the MAX40080. In blog 6, he showed his C Library for interfacing MAX40080 sensor using microcontrollers. In blog 8, he introduced his software utility which he created for using MXA40080 on Raspberry Pi from command line without the need to write any program. In blog 9, he showed how to measure power consumption of a flash drive connected to Raspberry Pi. In blog 10, he showed how to self measure power consumption of Raspberry Pi. In blog 11, he upgraded his setup for measuring power consumption of USB devices to support a USB Type-C device (iPhone) and measure its power consumption when charging. In blog 12, he used the MAX40080 CSA for long-time monitoring power consumption of barrel jack powered device. In blog 14, he experimented with overvoltage detection. Misaz covered a lot of ground in this problem and offered a lot of new content and ideas to the element14 community. For his hard work and achievements, we are proud to select him as Grand Prize Winner.
Runner Up Prize Winner: Gough Lui (lui_gough)
Gough Lui was selected by our judges as the runner up prize winner for "doing great job of measuring performance and testing some interesting applications." Initially, he challenged himself to upgrade a simple test instrument with capabilities usually found in higher end performance supplies or SMUs by using the MAX40080 Current Sense Amplifier. In blogs 2 and 3, he unboxed and set up the MAX40080. The blogs are informative and offer a great background. In Blog 4, he made current & voltage Measurement Accuracy tests and current & voltage measurement noise tests. He obtained some reading anomalies so he decided to experiment with a different platform, Arduino MKR WiFi 1010, to see if he could debug some of the issues. He wanted to use the MAX40080 in something practical, so he profiled the current of a blood pressure measurement and captured & reconstructed audio from measured current. He catalogued no less than 19 key learnings from his experiments in blog 6. He concludes, "The MAX40080 on the Current 6 Click proved to be quite a useful tool when it comes to upgrading the current measurement capability of a basic power supply. While it doesn’t quite measure-up to a full digitising power supply/source-measurement unit in both sample rate and low-current resolution as configured, it is quite inexpensive and the ~7.8kHz achieved sample rate is quite revealing with regards to the operational status of the blood pressure monitor tested, compared to the default 6-10Hz sample rate achievable from the metering built-in to such power supplies."
I'd like to thank all the element14 members who participated and completed this challenge, and who will receive a Finisher Prize for their work:
Current Monitoring for safer 3D Printers
aspork42's project blogs
Model Train Block Detection Using Current Sense
colporteur's project blogs
High Precision Calibration of Piezoresistive Pressure Sensors with the MAX40080
guillengap's project blogs
Rover Motor Control
milosrasic98's project blogs
Smart Power Bank Controller
taifur's project blogs
Electrical Bicycle Battery Consumption Monitor and Pedal Assistant Guiding System
vinayyn's project blogs
Predictive Maintenance of High Speed Telecom Equipment
vishwasn's project blogs
Last Word: A Big Thank You to Our Judges
I'd like to thank Doug Wong and Don Bertke for judging the Experimenting with Current Sense Amplifiers Challenge.
