The bq24650 is a highly integrated switch-mode battery charge controller. It provides input voltage regulation, which reduces charge current when input voltage falls below a programmed level. When the input is powered by a solar panel, the input regulation loop lowers the charge current so that the solar panel can provide maximum power output.

The bq24650 offers a constant-frequency synchronous PWM controller with high accuracy current and voltage regulation, charge preconditioning, charge termination, and charge status monitoring.

The bq24650 charges the battery in three phases: pre-conditioning, constant current, and constant voltage. Charge is terminated when the current reaches 1/10 of the fast charge rate. The pre-charge timer is fixed at 30 minutes. The bq24650 automatically restarts the charge cycle if the battery voltage falls below an internal threshold and enters a low quiescent current sleep mode when the input voltage falls below the battery voltage.

The bq24650 supports a battery from 2.1V to 26V with VFB set to a 2.1V feedback reference. The charge current is programmed by selecting an appropriate sense resistor. The bq24650 is available in a 16 pin, 3.5×3.5 mm2 thin QFN package.

• Maximum Power Point Tracking (MPPT) Capability by Input Voltage Regulation
• Programmable MPPT Setting
• 5V-28V Input Solar Panel
• 600kHz NMOS-NMOS Synchronous Buck Controller
• Resistor Programmable Float Voltage
• Accommodates Li-Ion/Polymer, LiFePO4, Lead Acid Chemistries
• Accuracy
  • ±0.5% Charge Voltage Regulation
  • ±3% Charge Current Regulation
  • ±0.6% Input Voltage Regulation
• High Integration
  • Internal Loop Compensation
  • Internal Digital Soft Start
• Safety
  • Input Over-Voltage Protection
  • Battery Temperature Sensing
  • Battery Absent Detection
  • Thermal Shutdown
• Charge Status Outputs for LED or Host Processor
• Charge Enable on MPPSET Pin
• Automatic Sleep Mode for Low Power Consumption
  • <15μA Off-State Battery Discharge Current
• Small 3.5 × 3.5 mm2 QFN-16 Package
• APPLICATIONS
  • Solar Powered Applications
  • Remote Monitoring Stations
  • Portable Handheld Instruments
  • 12V to 24V Automotive Systems
  • Current-Limited Power Source