MAX1772

19-1772; Rev 2; 5/02 Low-Cost, Multichemistry BatteryCharger Building Block General Description Features o Input Current Limiting o ±0.5% Output Voltage Accuracy Using Internal Reference (0°C to +85°C) o Programmable Battery Charge Current >4A o Analog Inputs Control Charge Current and Charge Voltage o Monitor Outputs for: Current Drawn from AC Input Source Charging Current AC Adapter Present o Up to 18.2V (max) Battery Voltage o 8V to 28V Input Voltage o >95% Efficiency o 99.99% (max) Duty Cycle for Low-Dropout Operation o Charges Any Battery Chemistry: Li+, NiCd, NiMH, Lead Acid, etc. MAX1772 The MAX1772 is a highly-integrated, multichemistry battery-charger control IC that simplifies the construction of accurate and efficient chargers. The MAX1772 uses analog inputs to control charge current and voltage and can be programmed by the host or hardwired. High efficiency is achieved by a buck topology with synchronous rectification. Maximum current drawn from the AC adapter is programmable to avoid overloading the AC adapter when supplying the load and the battery charger simultaneously. This enables the user to reduce the cost of the AC adapter. The MAX1772 provides outputs that can be used to monitor the current drawn from the AC adapter, battery-charging current, and the presence of an AC adapter. The MAX1772 can charge two to four lithium-ion (Li+) series cells, easily providing 4A. When charging, the MAX1772 automatically transitions from regulating current to regulatin...