TI BQ25155YFPR

The BQ25155 is a highly integrated battery charging management IC that integrates the most commonly used functions for wearable and portable devices, namely a regulated output voltage rail for system power, an ADC for battery and system monitoring, an LDO, and a button controller. The BQ25155 IC integrates a linear charger with PowerPath, enabling fast and accurate charging of small batteries while providing a stable voltage to the system. The stable system voltage (PMID) output can achieve optimal system operation through I²C based on the recommended operating conditions of the downstream IC and the system load. The device supports a charging current of up to 500mA and a termination current as low as 0.5mA for the most complete charging. The device charges the battery in three stages using a standard lithium-ion charging curve: pre-charging, constant current, and constant voltage regulation. The device integrates advanced power path management and control, allowing it to power the system while even charging the battery using a poor adapter. The host can also control the power path via I²C, allowing it to disconnect the input adapter and/or the battery without actually removing them. A single-button input eliminates the need for a separate button controller IC, reducing the overall solution footprint. The button input can be used for the wake-up function or to reset the system. A 16-bit ADC enables accurate battery voltage monitoring and can be used to implement low-Iq monitoring to monitor battery health. It can also be used to measure the battery temperature by using a thermistor connected to the TS pin and external system signals (via pins). Low quiescent current during operation and shutdown enables the longest battery life. The input current limit, charging current, LDO output voltage, and other parameters can be programmed via the I²C interface, making the BQ25155 a very flexible charging solution. The device includes a voltage-based JEITA-compliant (or standard hot/cold) battery pack thermistor monitoring input (TS) that monitors the battery temperature and automatically changes the charging parameters to prevent the battery from being charged at temperatures outside its safe temperature range. The temperature thresholds can also be programmed via I²C, allowing the host to customize the thermal load curve. The charger is optimized for a 5V USB input with an absolute maximum tolerance of 20V to withstand line transients. The device also integrates a linear regulator for providing a static rail to the radio or processor, which can be powered and controlled independently via I²C.

• Linear battery charger with fast charge current range of 1.25mA to 500mA
• I²C-programmable battery regulation voltage range of 3.6V to 4.6V in 10mV steps with 0.5% accuracy
• Configurable termination current, supporting as low as 0.5mA
• 20V-tolerant input with typical operating input voltage range of 3.4V to 5.5V
• Programmable thermal charge rate curve with fully configurable HOT, WARM, COOL, and COLD thresholds
• PowerPath management for system power delivery and battery charging
• I²C-programmable regulated system voltage (PMID) range of 4.4V to 4.9V, with battery voltage tracking and input pass-through options
• Dynamic power path management for optimized charging from weak adapters
• Advanced I²C control allows host to disconnect battery or adapter on demand
• I²C-configurable load switch or LDO output up to 150mA with programmable range of 0.6V to 3.7V in 100mV steps
• Ultra-low Iddq for extended battery life
• 10nA ship mode battery Iq
• 400nA Iq when powering the system (PMID and VDD on)
• Single-button wake and reset input via adjustable timer, supporting system power cycling and hardware reset
• 16-bit ADC
• Monitoring of charge current, battery NTC, and battery, input, and system (PMID) voltages
• General-purpose ADC input
• Always-on 1.8V VDD LDO supporting up to 10mA load
• 20-pin 2mm x 1.6mm CSP package
• 12mm² total solution size

• Headsets, earbuds, and hearing aids
• Smartwatches and smart trackers
• Wearable fitness and activity monitors
• Blood glucose monitors