1 Features
• Input voltage up to 30V tolerant
• Input Voltage Based Dynamic Power Management
(VINDPM)
• Automatic Sleep Mode for low power consumption
– 350nA battery leakage current
– 80μA input leakage current when charge
disabled
• Supports 1-cell Li-Ion, Li-Poly, and LiFePO4
• External resistor programmable operation
– VSET to set battery regulation voltage:
• Li-Ion: 4.05V, 4.35V, 4.4V, 4.53V, 4.58V
• LiFePO4: 3.5V, 3.6V, 3.7V
– ISET to set charge current from 10mA to
800mA
• High accuracy
– ±0.5% charge voltage accuracy
– ±10% charge current accuracy
• Charging features
– Precharge current 20% of ISET
– Termination current 10% of ISET
– NTC thermistor input to monitor battery
temperature
– TS pin for charging operation control over
JEITA range
– Open-drain output for status and fault indication
• Integrated fault protection
– 26V IN overvoltage protection
– VSET based OUT overvoltage protection
– 1000mA overcurrent protection
– 125°C thermal regulation; 150°C thermal
shutdown protection
– OUT short-circuit protection
– VSET, ISET pins short/open protection

2 Applications
• True wireless headsets
• Wearable accessories, smart band
• Beauty and grooming
• Electric toothbrush

3 Description
The BQ25176K is an integrated 800mA linear charger
for 1-cell Li-Ion, Li-Polymer, and LiFePO4 batteries
targeted at space-limited portable applications. The
device has a single power output that charges the
battery. The system load can be placed in parallel
with the battery, as long as the average system load
does not prevent the battery from charging fully within
the safety timer duration. When the system load is
placed in parallel with the battery, the charge current
is shared between the system and the battery.
The device has four phases for charging a Li-Ion/
Li-Poly battery: trickle charge to bring the battery
voltage up to VBAT_SHORT, precharge to recover a fully
discharged battery, fast-charge constant current to
supply the bulk of the charge, and voltage regulation
to reach full capacity.
In all charge phases, an internal control loop monitors
the IC junction temperature and reduces the charge
current if an internal temperature threshold, TREG, is
exceeded.
The charger power stage and charge current sense
functions are fully integrated. The charger function
has high accuracy current and voltage regulation
loops, charge status display, and automatic charge
termination. The charge voltage and fast charge
current are programmable through external resistors.
The precharge and termination current threshold track
the fast charge current setting.