TI battery charger achieves faster, cooler charging in mobile phones, portable electronics

3-MHz switch-mode Li-Ion charger with USB OTG support minimizes power dissipation, cuts board space in half

DALLAS (July 2008) -- Texas Instruments Incorporated (TI) (NYSE: TXN) introduced today a 3-MHz, switch-mode battery charge management integrated circuit (IC) for portable electronics that can be charged from an adaptor or a USB port. The tiny 2 mm x 2 mm switching charger, the bq24150, significantly improves charge time, reduces power dissipation and cuts board space in half compared to typical implementation with linear chargers. See: www.ti.com/bq24150-pr.

“USB charging continues to grow in popularity, primarily driven by the standardization of a mini-USB 5-V connector interface, the reduced use of inefficient AC/DC adapters and implementation of new Chinese charging specifications,” said Masoud Beheshti, manager of TI’s battery charge management products. “With billions of USB power ports installed in portable devices worldwide, incorporating TI’s new high-efficiency switching charger not only allows for quickly re-charging a battery from a USB port, it significantly reduces the amount of heat dissipation when charging - potentially saving consumers millions of watts per year.”

TI’s bq24150 device with integrated 1.25-A FETs is the industry’s smallest I2C programmable buck-charger solution, providing maximum battery charging performance and design flexibility in USB-powered applications, such as smart phones, portable media players or other consumer electronics. The 3-MHz charger only requires the use of a tiny 1-uH inductor and small ceramic capacitors, resulting in a solution size of 7.6 mm x 10.4 mm. The bq24150 also features a reverse boost USB On-the-Go (OTG) mode that generates a voltage supply to power accessories that are plugged into a mini-USB port, eliminating the need for another discrete device.

The bq24150 fully complies with USB charging standards. The device can achieve high peak efficiency of up to 92 percent, while supporting a USB battery charging current up to 900 mA. This speeds the charging rate without exceeding the 500-mA input current limit mandated by the USB standard. In addition, the bq24150 significantly reduces power dissipation, as compared to linear charging, making it ideal for high-performance, ultra-space constrained applications.

The device’s USB-friendly boot-up sequence allows the charge IC to boot autonomously, which helps replenish deeply discharged batteries. In addition, the bq24150 features input current sensing and offers multiple programmable charge parameters through an I2C communications interface.

Key technical features of the bq24150:

* USB-compliant mini-USB/AC adapter battery charger with reverse boost-mode operation for USB OTG 5-V Vbus generation
* Synchronous pulse-width modulation (PWM) with 3-MHz switching frequency
* High-efficiency conversion: 92 percent peak efficiency
* Smallest switch-mode charging solution: 2 mm x 2mm package, 1-uH chip inductor and low-value ceramic capacitors
* Maximum input voltage of 20 V (absolute max), 6 V (operation)
* +/-5 percent input current limit accuracy, +/-0.5 percent voltage regulation accuracy
* Programmable charge parameters through I2C communication interface (up to 3.4 Mbps)
* Safety timer with reset control
* Short-circuit, over-voltage and thermal protection

Pricing and availability

The bq24150 charger is available in volume today from TI and its authorized distributors. The device comes in a 20-ball, 2 mm x 2 mm chip-scale package. Suggested resale pricing in 1,000-piece quantities is $2.00. Evaluation modules of the bq24150, design application notes and TI’s easy-to-use online power management selection tool are available through power.ti.com.