DUAL-INPUT, USB/AC-ADAPTER, Li+ CHARGER WITH OVERVOLTAGE AND THERMAL REGULATION
SUNNYVALE, CA-July 31, 2003-Maxim Integrated Products
(NASDAQ: MXIM) introduces the MAX1874 dual-input, linear, single-cell lithium-ion (Li+) battery charger for charging from both USB and AC-adapter sources, enabling portable users to forego carrying a wall cube (this is protected by U.S. patent # 6,507,172). USB charging is particularly attractive for PDAs, cell phones, digital still cameras, MP3 players, and other hand-held products.
The MAX1874 accepts input voltages up to 6.5V (max) and does not require diodes or an external MOSFET. DC-input overvoltage protection up to 18V (max) can be added with a single SOT PFET. The device also features battery-to-DC power switchover to drive the system directly from the power source instead of the battery.
Thermal regulation of the charger temperature simplifies PC-board layout, minimizes component size guardbands, and maximizes the charging rate under all battery and input voltage conditions. Instead of shutting down when the thermal limit is reached, the MAX1874 simply reduces the charging current. In addition, ambient or battery temperature can be monitored with an external thermistor as a separate safety feature.
The MAX1874 is available in a 5mm x 5mm, 16-pin TQFN package and is specified for the extended-industrial temperature range (-40°C to +85°C). Prices start at $1.75 (1000-up, FOB USA). An evaluation kit is available to speed designs.
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