Global Sources
EE Times-Asia
Stay in touch with EE Times Asia
EE Times-Asia > Power/Alternative Energy
Power/Alternative Energy??

Integrated battery chargers target portable apps

Posted: 26 Nov 2008 ?? ?Print Version ?Bookmark and Share

Keywords:battery charger? Li-ion battery? power management? portable application?


Texas Instruments Inc. has launched four 28V, 1.5A linear charge management ICs with integrated FETs aimed at smart phones and other portable electronics.

The bq2407x family of Li-ion battery chargers allows an end-equipment to be powered directly from an external power source, even if the unit's battery pack is defective, fully discharged or absent.

TI's new bq24072, bq24073, bq24074 and bq24075 chargers integrate a high number of features in a 3mm x 3mm QFN. The chargers incorporate a 28V, 1.5A input FET, a 5A battery FET, current sensor, reverse blocking protection, thermal regulation and other battery management features. The devices support up to 1.5A in charging mode and up to 5A in discharge mode, which allows them to support higher currents from RF power amplifiers, such as those found in a GSM application.

The four bq2407x chargers also provide a unique power path management feature to simultaneously charge the battery and power the system. This reduces the number of charge and discharge cycles on the battery, enables proper charge termination and allows the system to turn on instantly, even if a battery is depleted. The battery charging rate is dynamically adjusted based on system voltage to ensure proper operation. Additionally, the battery can supplement the system's current requirements when an adapter cannot deliver the peak system currents, giving a designer the option of using a smaller adapter.

The battery chargers also offers an input voltage-based dynamic power management function in USB mode that monitors the input voltage and limits the input current if the input voltage drops below a preset value. This prevents the system from crashing USB sources that are incorrectly configured or poorly designed.

USB compliance
The bq2407x chargers support a high-input voltage rating of 28V with a 6.6V or 10.5V over-voltage protection threshold, which allows a designer to select an inexpensive adapter to help lower system cost. The adapter input current limit is programmable with a resistor up to 1.5A. In addition, the devices also comply with USB charging standards, such as USB-IF, by limiting the USB input current to 100mA or 500mA.

The devices charge the battery in three phases, including conditioning, constant current and constant voltage. System output voltage of the bq24072 automatically matches the battery's voltage. The bq24073 and bq24074 have a fixed output voltage of 4.4-V, while the bq24075 is set at 5.5-V. The bq24075 incorporates a battery SYSOFF function that disconnects the battery from the system, enabling a system with TI's bq27510 Impedance Track battery fuel gauge to measure open circuit voltage and predict remaining battery capacity.

All four bq2407x devices are available in volume. The devices come in a 16-lead, 3mm x 3mm QFN. Suggested resale pricing in 1,000-piece quantities is $1.60. Evaluation modules of the bq2407x family of chargers, design application notes, TI's Battery Charger Selection tool and Battery Chargers Catalog are available at

Article Comments - Integrated battery chargers target p...
*? You can enter [0] more charecters.
*Verify code:


Visit Asia Webinars to learn about the latest in technology and get practical design tips.

Back to Top