• 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 Pins
• 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

• Handheld Products
• Portable Media Players
• Industrial and Medical Equipment
• Portable Equipment

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 user- 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.