PMICs for hearables offer high efficiency at half the size

By Alix Paultre, contributing editor

The MAX77650/MAX77651 from Maxim provides highly integrated battery charging and power supply solutions for low-power wearable applications in which size and efficiency are critical. Both devices feature a SIMO buck-boost regulator that provides three independently programmable power rails from a single inductor to minimize total solution size. A 150-mA LDO provides ripple rejection for audio and other noise-sensitive applications. A highly configurable linear charger supports a wide range of Li+ battery capacities and includes battery temperature monitoring for additional safety (JEITA).

The devices include other features such as current sinks for driving LED indicators and an analog multiplexer that switches several internal voltage and current signals to an external node for monitoring with an external ADC. A bidirectional I² C interface allows for configuring and checking the status of the devices. An internal on/off controller provides a controlled startup sequence for the regulators and provides supervisory functionality when the devices are on. Numerous factory programmable options allow the device to be tailored for many applications, enabling faster time-to-market.