Tiny Power Managers Drive White LEDs

Measuring just 1.5 mm x 1.5 mm, the TPS6106x family of synchronous-boost dc/dc converters support input voltages from 2.7V to 6V and can power up to three, four, and five white LEDs in series. The TPS61060, TPS61061, and TPS61062 devices integrate a 400-mA power MOSFET and synchronous rectifier, eliminating the need for an external series Schottky diode. They operate at a fixed frequency of 1 MHz, which allows the converters to work with smaller, low-value external components, such as a 10 µH inductor and a 220 nF output capacitor. Other features include digital dimming, over-voltage and short circuit sensing, and thermal shutdown. Each device has a different over-voltage protection threshold (14V, 18V and 22.75V) corresponding to the maximum number of series LEDs. In shutdown, the parts consume less than 3 µA. Prices for the TPS61060, TPS61061, and TPS61062 are $1.35, $1.40, and $1.45 each/1,000, respectively. TEXAS INSTRUMENTS INC., Dallas, TX. (800) 477-8924.