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.