Elete model DC/DC converter for 1A current white LED driver

Elete (Linear Technology) days before the launch of synchronous buck boost DC/DC converter LTC3454, the device can optimize the input from a single lithium battery, with 1A current drive single high current white LED. According to the difference between the input voltage and the maximum forward voltage of the LED, the regulator operates in synchronous buck, synchronous boost or buck boost mode. This feature is especially important in high current LED applications. Depending on the current value, the LED forward voltage may vary from 2.7V to 4.9V. In addition, the device uses proprietary architecture to achieve 90% efficiency over the entire Li ion battery voltage range (2.7V to 4.2V). The LED current can be programmed with two current setting resistors and two enable pins into one of the 4 current values (including shutdown). In shutdown, the supply current is less than 1uA. In the flashlight mode, the device efficiency is typically greater than 90%, the efficiency of flash mode is 80%; the current input range of 2.7V to 5.5V, and provide a continuous output current up to 1A, LED current programming with 3.5% accuracy. The device can carry out internal soft start with open / short circuit LED protection function. The LTC3454 can maintain 1MHz constant frequency operation, thus allowing the use of small inductors. Its shutdown current is less than 1uA, and provides overheating protection function.