Maxim Integrated Products introduces the MAX1879, which is a safe, simple, and inexpensive single-cell lithium-ion (Li) battery pulse charger that does not dissipate heat. Its small size and low heat enables the charging function to be incorporated into cell phones, PDAs, and other portable equipment.
The MAX1879 is an upgrade to the popular MAX1679, incorporating more safety features like a built-in 6.25hr timer to prevent infinite trickle-charging. Other safety features include continuous over/undervoltage protection, ± .75% charge voltage tolerance,
precharging near-dead cells prior to fast-charging, and over/undertemperature sensing.
The MAX1879 and an external P-channel MOSFET make a complete stand-alone charger for a single-cell Li+ battery. An inexpensive current-limited wall cube sets the charging current, and the external FET is pulsed either on or off, so that unlike a linear regulator, the MAX1879 dissipates virtually no power. The MAX1879 accepts inputs of 5 V to 22 V. Charge current is up to 800 mA.
The MAX1879 comes in a 1.1 mm high 10-pin μ>MAX package and is screened for the extended-industrial temperature range (-40deg>C to +85deg>C).