Catalog
4A, High Efficiency, Li-Ion Battery Charger
Key Features
• Charger Controller for 3- or 4-Cell Lithium-Ion Batteries
• High Conversion Efficiency: Up to 96%
• Output Currents Exceeding 4A
• ±0.8% Charging Voltage Accuracy
• Built-In Charge Termination for Li-Ion Batteries
• AC Adapter Current Limiting Maximizes Charge Rate
• Thermistor Input for Temperature Qualified Charging
• Wide Input Voltage Range: 6V to 28V
• 0.5V Dropout Voltage; Maximum Duty Cycle: 98%
• Programmable Charge Current: ±4% Accuracy
• Indicator Outputs for Charging, C/10 Current Detection, AC Adapter Present, Low Battery, Input Current Limiting and Faults
• Charging Current Monitor Output
• Available in a 24-Pin 4mm × 5mm QFN Package
Description
AI
The LTC4007-1 is a constant-current/constant-voltage charger controller for 3- or 4-cell lithium-ion batteries. The PWM controller uses a synchronous, quasi-constant frequency, constant off-time architecture that will not generate audible noise even when using ceramic capacitors. Charging current is programmable to ±4% accuracy using a programming resistor. Charging current can also be monitored as a voltage across the programming resistor.The output float voltage is pin programmed for cell count (3 cells or 4 cells) and chemistry (4.2V/4.1V). A timer, programmed by an external resistor, sets the total charge time.The LTC4007-1 includes a thermistor input, which suspends charging if an unsafe temperature condition is detected. If the cell voltage is less than 3.25V, a low-battery indicator asserts and can be used to program a trickle charge current to safely charge depleted batteries. TheFAULTpin is also asserted and charging terminates if the low-battery condition persists for more than 1/4 of the total charge time.LTC4007LTC4007-1Low battery threshold 4.2V cell2.5V3.25VLow battery threshold 4.1V cell2.44V3.173VRestartEnabledDisabledPackageSSOP-24QFN-24ApplicationsNotebook ComputersPortable InstrumentsBattery-Backup SystemsLi-Ion Chargers