Power optimization has become a basic requirement in most applications, but fitness ear wearables bring unique problems beyond the requirements of traditional "wireless" headphones. Traditional headphones use a Bluetooth connection to stream audio, but retain a wired connection to the battery. Batteries are usually packaged in in-line packages along with volume controls and power connectors. By contrast, the true wireless design eliminates all wired connections and requires product designers to build rechargeable batteries into each earbud.
Therefore, systems engineers must find design solutions that meet tight packaging requirements while ensuring extended battery life and simplifying the battery charging process for users.
This paper discusses how to effectively extend battery life and simplify battery charging while providing multiple power rails for the underlying biosensing, audio, and processor devices of these designs. This will be followed by a brief explanation of how wireless charging works, followed by standards-based wireless power solutions that allow developers to quickly build complex real wireless products and take advantage of the rapidly evolving third-party compatible charging platforms. The solutions to be presented are from vendors such as Maxim Integrated, Analog Devices, STMicroelectronics, and Texas Instruments.
In addition to being feature-rich, these SOCs integrate their own power management capabilities to power different power domains from a single source in a variety of ways using low-power operating modes, clock or voltage gating functions, or internal regulators. Although these features help to simplify the implementation of power supply optimization designs, they often entail the requirement of multiple power rails to fit each device. For example, the SoC discussed earlier in this series (Maxim Integrated MAXM86161 biosensor, MAX98090 audio codec; And ON Semiconductor's RSL10 Bluetooth microcontroller) have different power supply requirements
