1 Features
1• 1.6-MHz Synchronous Switched-Mode Charger
with 4-A Integrated N-MOSFETs
• Up to 94% Efficiency
• 30-V Input Rating with Adjustable Overvoltage Protection
– 4.5-V to 17-V Input Operating Voltage Range
• Battery Charge Voltage
– bq24170: 1-, 2-, or 3-Cell with 4.2 V/Cell
– bq24172: Adjustable Charge Voltage
• High Integration
– Automatic Power Path Selector Between
Adapter and Battery
– Dynamic Power Management
– Integrated 20-V Switching MOSFETs
– Integrated Bootstrap Diode
– Internal Digital Soft Start
• Safety
– Thermal Regulation Loop Throttles Back
Current to Limit TJ = 120°C
– Thermal Shutdown
– Battery Thermistor Sense Hot/Cold Charge
Suspend and Battery Detect
– Adjustable Input Overvoltage Protection
– Cycle-by-Cycle Current Limit
• Accuracy
– ±0.5% Charge Voltage Regulation
– ±4% Charge Current Regulation
– ±4% Input Current Regulation
• <15-μA Battery Current With Adapter Removed
• <1.5-mA Input Current With Adapter Present and
Charge Disabled

2 Applications
• Tablet PCs
• Portable Data Capture Terminals
• Portable Printers
• Medical Diagnostics Equipment
• Battery Bay Chargers
• Battery Backup Systems

3 Description
The bq2417x device is a highly integrated stand-
alone Li-Ion and Li-Polymer switched-mode battery
charger with two integrated N-channel power
MOSFETs. The device offers a constant-frequency
synchronous PWM controller with high-accuracy regulation of input current, charge current, and
voltage. The bq2417x closely monitors the battery
pack temperature to allow charge only in a preset
temperature window. The bq24170 charges one, two,
or three cells (selected by CELL pin), and the bq24172 is adjustable for up to three series Li+ cells.