High Efficiency Synchronous Switch-Mode Charger Controller – Solar Battery Charger


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
    • Solar Powered Applications
    • Remote Monitoring Stations
    • Portable Handheld Instruments
    • 12V to 24V Automotive Systems
    • Current-Limited Power Source

Source: http://www.ti.com/product/bq24650?DCMP=hpa-pmp-bq34z110-en&HQS=bq24650-pr