Reference Guide

Description

MAXREFDES1302 is a reference design for TWS application based on the Maxim 1-Wire^® solution. This reference design provides power and battery management solutions for the TWS cradle and earbuds (right & left), including battery charging, battery monitoring, and power management. An OLED display is mounted on the cradle side to display earbud connection state, state-of-charge (SOC in %) and remaining capacity (CAP in mAh) of batteries of the cradle and earbuds. A serial port monitor can also be used to show such information.

On the cradle side, USB Type-C^® charging is realized by the MAX77751, which integrates a 3.15A switch charger and BC1.2. Also, USB Type-C Configuration Channel (CC) detection pins of the MAX77751 enable automatic USB Type-C power source detection and input current limit configuration. The MAX17262 is used to monitor battery remaining capacity and state-of-charge of the batteries. The MAX17262 implements the Maxim ModelGauge™ m5 EZ algorithm and features internal current measurement for up to 3.1A pulse currents. The MAX17224 is an ultra-low quiescent current boost DC-DC converter with a 225mA/0.5A/1A peak inductor current limit and True Shutdown™. The MAX38640 is nanoPower family of ultra-low 330nA quiescent current buck (step-down) DC-DC converters that operate from 1.8V to 5.5V input voltage and support load currents of up to 175mA with peak efficiency of 96%. While in shutdown, there is only 5nA of shutdown current. The MAX32655 microcontroller is used to configure the fuel gauge, 1-Wire communication, and 1-Wire power transfer.

On the earbud side, the DS2488 provides a cost-effective solution for power transfer and communication between the TWS cradle and earbuds. The DS2488 is a low-cost simple bridge device with a single dedicated contact on each side of the bridge which enables power delivery for the battery charging, small message exchange, and the state reporting between two microcontroller-based subsystems. The battery management system for earbuds consists of the MAX77734 and MAX17262. The MAX77734 provides highly integrated battery charging and power supply solutions for the low-power applications where size and efficiency are critical. The MAX32655 on the earbud side configures the MAX77734, MAX17262, DS2488 and MAX98050. The MAX98050 is a low-power, high-performance audio codec with integrated low-latency digital filters for wireless hearables, headsets, and headphones.

Features

• Integrated solution
• Small size
• Low power
• High accuracy
• Low cost