LY6394TA

This is a fully integrated power management IC designed for Bluetooth charging cases, incorporating lithium battery charge management, a synchronous boost converter, battery fuel gauge, and protection function modules. The IC integrates an NTC temperature protection function, requiring only a single NTC resistor to monitor lithium battery temperature during both charging and discharging. It supports trickle, constant-current (CC), and constant-voltage (CV) charging, including 0V battery charging. When the battery voltage is below 2.9V, the IC enters trickle charge mode at 0.12× the CC charge current; above 2.9V, CC mode is applied; when the battery voltage approaches 4.2V and the charge current drops to 0.15× the CC current, charging terminates. The IC continuously monitors battery voltage and initiates a new charge cycle when the voltage falls below the recharge threshold of 4.0V, maintaining the battery at full charge. The built-in power path management allows the input power source to simultaneously charge the case battery and power the Bluetooth earbuds via the output port — earbud charging is unaffected even when the battery voltage is 0V. The IC features adapter adaptability, automatically adjusting charge current based on the adapter's output capability and charging cable resistance to prevent charging anomalies or adapter damage. Charge current is selectable between 200mA and 300mA; charge currents below 200mA can also be achieved by connecting a series input resistor. The default full-charge voltage is 4.2V, with 4.3V and 4.35V versions available upon customization. In standby mode, the IC activates boost output upon detecting a load at the output port; when the load current remains below 7mA for 8 consecutive seconds, the IC automatically shuts down, with a standby current of 4.5µA. The output standby voltage can be set to either a fixed 2V mode or battery voltage mode. A built-in soft-start circuit suppresses inrush current during boost startup; the switching frequency is 1MHz, the maximum output current is 500mA, and the IC enters pulse-skipping mode under light load to reduce losses. The IC provides comprehensive protection features, including: thermal protection (current limiting at a junction temperature of 110°C, shutdown at 140°C); output short-circuit/overload protection (latch-off requiring removal of the short-circuit condition or reconnection of the load/charger to recover); battery undervoltage protection (output disabled when battery voltage falls below 2.8V during discharge, requiring a recharge to above 3.2V to recover); and input undervoltage protection (charge path disabled when input voltage falls below 4.1V to prevent battery reverse current). The NTC protection function monitors battery temperature by sensing the resistance at the NTC pin. Using the default NTC resistor with a value of 10K and β=3950, the normal operating temperature range for charging is 0°C < T < 43°C, and for discharging is -10°C < T < 57°C. The temperature protection thresholds can be adjusted by connecting resistors in parallel or series.

Applications

• Bluetooth earphone charging case
• Portable lithium battery applications

Key features

• NTC support
• Auto-shutdown current at light load: 7mA
• Standby voltage: 2V or battery voltage selectable
• Adapter adaptive voltage: 4.6V
• Standby current: 4.5uA
• Charge current: 200mA/300mA selectable
• Maximum discharge current: 500mA
• Output overvoltage, short-circuit, and overcurrent protection
• Intelligent temperature control
• 1/2/3/4-LED battery level indication
• Boost efficiency up to 93%
• ESOP8 package