Constant Voltage

When batteries are used to power a circuit, there is always the problem that the battery voltage drops during operation. A National Semiconductor type LM3354 IC (www.national.com/0ds/LM/LM3354.pdf) can provide a solution to this problem. It contains a dc/dc converter that operates as a buck converter in step-down mode when the input voltage is too high, and which can also handle input voltages that are too low by operating as a boost converter in step-up mode.