MAX1645

19-1566; Rev 2; 1/01 Advanced Chemistry-Independent, Level 2 Battery Chargers with Input Current Limiting 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-tooutput voltage drop by allowing the duty cycle to exceed 99%. The MAX1645 can easily charge one to four series Li+ cells. o Input Current Limiting o 175s Charge Safety Timeout o 128mA Wake-Up Charge o Charges Any Chemistry Battery: Li+, NiCd, NiMH, Lead Acid, etc. o Intel SMBus 2-Wire Serial Interface o Compliant with Level 2 Smart Battery Charger Spec Rev. 1.0 o +8V to +28V Input Voltage Range o Up to 18.4V Battery Voltage o 11-Bit Battery Voltage Setting o ±0.8% Output Voltage Accuracy with Internal Reference o 3A max Battery Charge Current o 6-Bit Charge Current Setting o 99.99% max Duty Cycle for Low-Dropout Operation o Load/Source Switchover Drivers o >97% Efficiency Features MAX1645/MAX...