USB IC Allows Batteries To Be Charged During System Operation

The LTC4410 USB power manager allows simultaneous battery charging and system operation of a Li-Ion powered USB peripheral from a USB host. The IC powers the system load directly from the USB's 5V supply instead of the battery's 3.6V terminal, reportedly resulting in up to a 39% faster charge time than achieved by current methods. And it ensures that a connected device is in compliance with USB over-current specifications by keeping the total current constant from the USB port. This is done by adjusting the charge current relative to the amount of current needed by the system load. Other LTC4410 features include a minimum voltage drop of 100 mV at 500 mA, battery drain of 1 µA, and over-temperature protection. Additionally, a reverse-current-blocking diode is not required. The IC is compatible with the company's LTC4053 and LTC1733 linear battery chargers. Housed in a six-lead ThinSOT package, the chip has a starting price of $1.20 each/1,000. LINEAR TECHNOLOGY CORP., Milpitas, CA. (800) 454-6327.