1 Features

1• Ideal For Highly Efficient Charger Designs For

Single-, Two-, or Three-Cell Li-Ion and Li-Polymer

Battery Packs

• bq24105 Also for LiFePO4 Battery (see Using

bq24105 to Charge the LiFePO4 Battery)

• Integrated Synchronous Fixed-Frequency PWM

Controller Operating at 1.1 MHz With 0% to 100%

Duty Cycle

• Integrated Power FETs for Up To 2-A Charge

Rate

• High-Accuracy Voltage and Current Regulation

• Available in Both Stand-Alone (Built-In Charge

Management and Control) and System-Controlled

(Under System Command) Versions

• Status Outputs for LED or Host Processor

Interface Indicates Charge-In-Progress, Charge

Completion, Fault, and AC-Adapter Present

Conditions

• 20-V Maximum Voltage Rating on IN and OUT userPins

• High-Side Battery Current Sensing

• Battery Temperature Monitoring

• Automatic Sleep Mode for Low Power

Consumption

• System-Controlled Version Can Be Used in NiMH

and NiCd Applications

• Reverse Leakage Protection Prevents Battery

Drainage

• Thermal Shutdown and Protection

• Built-In Battery Detection

• Available in 20-Pin, 3.50 mm × 4.50 mm VQFN

Package

2 Applications

• Handheld Products

• Portable Media Players

• Industrial and Medical Equipment

• Portable Equipment

3 Description

The bqSWITCHER™ series are highly integrated Li-

ion and Li-polymer switch-mode charge management

devices targeted at a wide range of portable

applications. The bqSWITCHER™ series offers

integrated synchronous PWM controller and power FETs, high-accuracy current and voltage regulation,

charge preconditioning, charge status, and charge

termination, in a small, thermally enhanced VQFN

package. The system-controlled version provides

additional inputs for full charge management under

system control.

The bqSWITCHER™ charges the battery in three

phases: conditioning, constant current, and constant

voltage. Charge is terminated based on userPins

selectable minimum current level. A programmable

charge timer provides a safety backup for charge

termination. The bqSWITCHER™ automatically

restarts the charge cycle if the battery voltage falls

below an internal threshold. The bqSWITCHER™

automatically enters sleep mode when VCC supply is

removed.