General Description

The MAX1645 are high-efficiency battery chargers capable of charging batteries of any chemistry type. It uses the Intel System Management Bus (SMBus?) to control voltage and current charge outputs.

When charging lithium-ion (Li+) batteries, the MAX1645 automatically transition from regulating current to regulating voltage. The MAX1645 can also limit line input current so as not to exceed a predetermined current drawn from the DC source. A 175s charge safety timer prevents “runaway charging” should the MAX1645 stop receiving charging voltage/ current commands.

The MAX1645 employs a next-generation synchronous buck control circuity that lowers the minimum input-to-output voltage drop by allowing the duty cycle to exceed 99. The MAX1645 can easily charge one to four series Li+ cells.

Features

? Input Current Limiting

? 175s Charge Safety Timeout

? 128mA Wake-Up Charge

? Charges Any Chemistry Battery: Li+, NiCd, NiMH, Lead Acid, etc.

? Intel SMBus 2-Wire Serial Interface

? Compliant with Level 2 Smart Battery Charger Spec Rev. 1.0

? +8V to +28V Input Voltage Range

? Up to 18.4V Battery Voltage

? 11-Bit Battery Voltage Setting

? ±0.8 Output Voltage Accuracy with Internal Reference

? 3A max Battery Charge Current

? 6-Bit Charge Current Setting

? 99.99 max Duty Cycle for Low-Dropout Operation

? Load/Source Switchover Drivers

? >97 Efficiency

Applications

Notebook Computers

Point-of-Sale Terminals

Personal Digital Assistants