Click on the advert above to visit the company web site

Product category: Power Supply ICs and Controllers
News Release from: Texas Instruments (April 2001-March 2006) | Subject: bq2420x family
Edited by the Electronicstalk Editorial Team on 4 October 2001

Battery charge managers keep their cool

A new family of single-chip charge management ICs from Texas Instruments enable designers to reduce heat dissipation in portable systems by more than 70% compared with linear chargers

By integrating the charge control mosfet and current sensor in a small 8-pin MSOP package, the family offers a true single-chip solution, requiring only two small external capacitors for operation. Designed for use in space-limited portable applications where reducing the internal power dissipation is critical, this family is ideal for systems using single Li-ion or Li-polymer batteries.

The bq2420x family includes a current sensor and an internal mosfet pass transistor, rated for up to 500mA charge applications.

With this high degree of integration, designers are able to build a full battery charger circuit using a single 8-pin MSOP package with a 15.2mm?

footprint.

The bq2420x family completes the charge cycle in three phases: conditioning, current-limit and constant voltage.

During the conditioning phase, the bq2420x applies a gentle precharge current to revive a deeply discharged battery.

Following this phase, the bq2420x relies on an inexpensive current-limited external power source to charge the battery.

This topology removes more than 70% of the heat generated in the system using a similar linear charger without sacrificing safety or charge capacity.

Finally, an accurate voltage-regulation phase completes the battery charge and the internal reference is trimmed to within +/-0.5% across the operating temperature and voltage range.

In addition, the bq2420x safely terminates charge when a minimum current is reached or if the battery current fails to reach minimum voltage levels after a given time.

Other novel features include: short-circuit and thermal protection for the internal mosfet; an automatic sleep mode for low power consumption (typically less than 4uA); direct battery connection without precision sense resistors; charge status output for LED or host processor interface indicates charge-in-progress, full-capacity and fault conditions; automatic battery recharge; and optional battery temperature monitoring before and during charge.

Samples of the bq2420x are available now with volume production planned for 4Q 2001.

The device is available in two fixed voltage versions for single-cells with either coke (4.1V) or graphite (4.2V) anodes.

Devices rated for higher charge currents will also be available later this year.

• Texas Instruments (April 2001-March 2006): contact details and other news
• Email this article to a colleague
• Register for the free Electronicstalk email newsletter
•
• Electronicstalk Home Page

Search the Pro-Talk network of sites

Put your news on Electronicstalk  |   Advertise  |   Get the free Electronicstalk newsletter
Electronicstalk Home  |   About Electronicstalk  |   Copyright © 2000-2007 Pro-Talk Ltd, UK