Dual Input Li+ Charger and Smart Power Selector Eliminates the Need for External MOSFETs
SUNNYVALE, CAMaxim Integrated Products introduces the MAX8677A, dual input USB/AC-adapter linear charger with Smart Power Selector for portable devices powered by rechargeable single-cell Li+ batteries. This charger integrates all of the power switches required for charging and switching the load between the battery and external power, thus eliminating the need for external MOSFETs. MAX8677A is ideal for portable applications, such as smartphones, PDAs, portable media players, GPS navigation devices, digital still cameras, and digital video cameras.
The MAX8677A can operate either from separate inputs for USB and AC-adapter power or from a single input that accepts both. When external power is connected, the Smart Power Selector allows the system to operate with no battery or a deeply discharged battery. It automatically switches the system load from the battery and makes the best use of limited USB or adapter power while charging the battery from input power not used by the system. All necessary current-sense circuitry is included on-chip with the integrated power switches.
The DC input's current limit is adjustable up to 2A, and both DC and USB inputs support 100mA, 500mA, and USB-suspend modes. Charge current is adjustable up to 1.5A to support a wide range of battery capacities. Other MAX8677A features include thermal regulation, overvoltage protection, charge status and fault outputs, power-OK monitors, a battery thermistor monitor, and a charge timer.
The MAX8677A is available in a space-saving, thermally enhanced, 4mm x 4mm, 24-pin TQFN package that is specified for the extended temperature range (-40 degrees Celsius to +85 degrees Celsius). Prices start at $1.95 (1000-up, FOB USA). An evaluation kit is available to speed designs.