ICs Allow Charging From USB

Taking center stage as the market's smallest and most integrated, single-cell Li-Ion and Li-Pol battery chargers, the bqTINY-II series ICs allow users to charge a variety of portable products from either an ac adapter or a USB port. Charge rates of 100 mA and 500 mA can be selected in the USB mode. In the ac adapter mode, an integrated FET provides charge current up to 1A. The 3 x 3-mm chargers include a programmable current set point, eliminating the need for external resistors. Integrated features include voltage and current regulation, timers for pre- and fast-charge phases, charge-status outputs, temperature sensing, and charge termination. Battery charging is conducted in three phases: pre-charge conditioning, constant current, and constant voltage. The three devices currently in the power manager series each provide current sense, 4.2V regulation, and charge enable. The bq24020 includes temperature sense; the bq24022 provides an ac-present indicator; and the bq24023 provides both timer and termination enable. All three also feature a unique deep-sleep mode that prevents battery drainage in the absence of input power. Available in 10-lead QFN packages, the devices cost $2.09 each/1,000. TEXAS INSTRUMENTS INC., Dallas, TX. (800) 477-8924, ext. 4500.