The fast-growing wearables market is rapidly evolving from devices that are primarily fitness-oriented to those that are intended to provide more sophisticated data and information on the health and wellbeing of users. As a result, continuous heart-rate-monitoring functionality is increasingly becoming a key requirement for these types of devices. This presents a huge challenge for wearable developers in balancing the limited battery resource available on wearable devices and the need for continuous HRM.
The joint solution from PixArt and Ambiq Micro now truly enables the ‘always-on’ sensing functionality for makers and OEMs looking to deliver the next generation of product for wearable health and wellness applications. Delivering a world-class power consumption figure of less than 350µA total power in continuous operation, the solution combines Ambiq Micro’s advanced Apollo ARM M4 with floating point unit MCU, which acts as the main processor in this advanced HRM solution, together with PixArt’s unique CMOS-sensor-based Heart Rate Monitor Family.
PixArt’s Heart Rate Monitor sensor deploys the photoplethysmogram (PPG) technique, which transmits LED light waves into the skin of the user and measures the response change caused by absorption due to pulsating arterial blood. Outputting captured PPG data from the user, these measurements can be used to monitor heart rate and stress levels.
Based on the 32-bit ARM® Cortex-M4F processor core, in real-world applications the Apollo MCU from Ambiq Micro delivers typically 5 to 10 times lower energy consumption than other competitive MCUs that offer comparable performance. This high level of performance per watt can mean significantly extended battery life, which is critical for wearable electronics and battery-powered applications.
The dramatic reduction in energy consumption is achieved using Ambiq’s patented Subthreshold Power Optimized Technology (SPOT) platform. In addition, the Apollo MCU optimizes both active- and sleep-mode power – a technique that is unique in the industry. The MCU consumes an industry-leading 34µA/MHz when executing instructions from flash memory and features average sleep-mode currents as low as 140nA.