Psst…This Fitness Wearable Tells You Your Body’s Secrets

March 10, 2020

Christine Young  By: Christine Young
 Blogger, Maxim Integrated 


Low-Power Microcontroller for WearablesFitness trackers have come a long way since a professor from the University of Oulu in Finland invented the first battery-operated, fingertip heart-rate monitor for the Finnish National Cross Country Ski team in 1977. Today's wearables come in a variety of form factors and monitor a wide range of human body signals, including pulse/heart rate, blood-oxygen levels, electrocardiogram (ECG), UV light, and temperature. Knowing these data points gives us insights into various fitness and wellness conditions, like heart health, sleep quality, stress, and athletic performance.

One fitness wearable geared toward helping people—athletes, in particular—optimize their performance is the WHOOP Strap 3.0. The strap plus an accompanying app tells users about recovery, strain, and sleep. The idea behind this solution is that by balancing the insights gained from each of these areas, users can enhance their training regimen and, according to Boston-based WHOOP, "unlock the secrets to your body's true potential."

Membership in the WHOOP community includes access to the app that provides these core analytics:

  • Recovery status, a parameter which includes heart-rate variability (HRV) and indicates how lifestyle and training affect the body's recovery
  • Instant performance feedback, including tracking of activities and calories burned
  • Sleep performance, efficiency, and consistency

When the WHOOP team was ready to develop the latest generation of its fitness strap, the engineers needed underlying technology that would allow them to enhance the wearable device's capabilities. On their wish list: local processing of acquired user data and longer battery life (up to five days) with the same form factor as the 2.0 device.

WHOOP integrated several Maxim ICs into the WHOOP Strap 3.0:

  • MAX32652 ultra-low-power Arm® Cortex®-M4 with floating point unit-based microcontroller. This DARWIN MCU provides 3MB flash, 1MB SRAM, and multiple memory-expansion interfaces, ideal for supporting complex, battery-powered applications.
  • MAX14745 power management IC with ultra-low IQ voltage regulators and battery charger. Its 200mA buck regulators have 0.9µA (typical) of quiescent current, while one of its three LDOs has just 0.6µA (typical) of quiescent current and the other two both have 1µA (typical) of quiescent current.
  • MAX17223 nanoPower synchronous boost converter with True Shutdown™, which has 300nA quiescent supply current into OUT and provides 95% peak efficiency

The microcontroller plus the power management ICs support the high levels of processing power and low power consumption that WHOOP wanted for the latest generation of its fitness device. To learn more about how the company met its design challenges, read the WHOOP testimonial. You can also evaluate the MAX32652 for your next high-performance, battery-powered application by purchasing the MAX32650-EVKIT# evaluation kit.