Electronic Design

Lithium Battery-Charger IC Integrates FETs To Drive 2 A For Fast Charging

Consumers not only want long battery life, they also want to charge their batteries in next to no time. So, here is a synchronous, switch-mode battery-charger IC to fill the bill.

The bq24100 from Texas Instruments includes power FETs that can source 2 A of charge current to one-, two-, and three-series cell lithium-ion (Li-ion) or lithium-polymer (Li-poly) battery packs for DVD/media players and smart handhelds. It provides precise regulation plus charge status outputs. It also terminates charging when the battery is full or a timer expires.

This chip works strictly with Li-ion or Li-poly batteries, which it charges in three phases: conditioning, for deeply discharged batteries; constant-current fast-charge; and constant-voltage. Also, the chip terminates charge when it detects a pre-set current level. If the battery voltage falls below a threshold, the chip automatically re-starts. If the external charging supply is removed, the battery won't discharge through the chip. For special cases, another version of the chip can run an MCU-programmed charge profile.

All of this functionality squeezes into a 3.5- by 4.5-mm QFN package. The bq24100 operates from 3.5 to 16 V. It switches at 1.1 MHz. Pricing is $2.10 each in thousand-unit lots. Application notes and a reference design are available

Texas Instruments Inc.
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