1 Features

• Input voltage up-to 30-V tolerant

• Automatic Sleep Mode for low power consumption

– 350-nA battery leakage current

– 85-μA 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: 4.05 V, 4.1 V, 4.2 V, 4.35 V, 4.4 V

• LiFePO4: 3.5 V, 3.6 V, 3.7 V

– ISET to set charge current from 10 mA to 800

mA

• 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 function control

– Open-drain output for status and fault indication

– Open-drain output for power good indication

• Integrated fault protection

– 6.6-V IN overvoltage protection

– VSET based OUT overvoltage protection

– 1000-mA 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

• Fleet management, asset tracking

3 Description

The BQ25170 is an integrated 800-mA 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 three phases for charging a Li-Ion

battery: 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.