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USB/AC battery charger ICs leave compact footprint

Posted: 02 Aug 2007 ?? ?Print Version ?Bookmark and Share

Keywords:USB/AC battery charger ICs? digital thermal regulation circuit?

AnalogicTech has introduced a comprehensive line of USB/AC battery charger ICs for portable systems operating off single-cell 4.2V (4.375V) Li-ion/polymer batteries. Integrating various features into a highly compact footprint and requiring just a single external component, the new devices offer a complete USB/AC charging function.

Designers of cellular handsets, Bluetooth headsets, MP3 players and digital cameras must offer comprehensive USB/AC charging capability while sacrificing as little of their limited product footprint as possible. By offering different choices from comprehensive solutions with integrated digital thermal regulation to relatively basic alternatives with automatic trickle charge and battery pre-conditioning options in extremely compact packages, the product family is said to enable the optimal solution in the smallest footprint for their target market.

AAT3683 offers the most comprehensive feature set in the new product family. The single-input USB/AC charger supports programmable charge currents up to 1A. Operating off a voltage input range of 4-6.5V, AAT3683 integrates a charging device, reverse blocking diode and current sensing to regulate battery charge voltage and current for 4.2V (4.375V) Li-ion/polymer battery cells.

The battery charger IC includes a digital thermal regulation circuit developed and patented by AnalogicTech that automatically reduces the charging current when the internal temperature of the die exceeds a preset limit to prevent the device from thermal shutdown. This feature helps minimize charge time by maintaining the maximum possible battery charging current for a given set of input to output, power dissipation and ambient temperature conditions.

The AAT3683 IC comes with an integrated charge timer that automatically terminates charging functions if a defective battery cell does not accept a charge over a preset period of time.

The device has a charge current programmable from 15 to 500mA and offers automatic trickle charge for battery pre-condition as a standard feature. The optional AAT3684-1 version comes without the trickle charge capability.

Designed for space-constrained, portable applications requiring up to 500mA from either a USB or AC source, the AAT3681A is also available with a variety of trickle charge, active enable high and low, and charge termination threshold current options. Each of the new charger ICs offer overvoltage, short-circuit and overtemperature protection. AAT3683 adds overcurrent protection.

All three devices are specified across the -40C to 85C temperature range. AAT3681A is available in a Pb-free, 8-pin, 2mm x 2.1mm SC70JW package. AAT3683 is available in Pb-free, 10-pin 2.2mm x 2.2mm STDFN and 16-pin QFN-33 packages. The AAT3684 is available in a 10-pin 2.2mm x 2.2mm STDFN package.

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