If we want to obtain a 5V voltage from only 2 NiMH batteries, we´ll face the fact, that the most of common DC/DC circuits doesn´t operate at such a low voltage. LT1304 controller belongs among circuits, which handle this situation without problems and it also provides several extra things.
To obtain 3.3 or 5V from a lower voltage is a typical requirement at battery-powered or portable devices. Naturally, to obtain 5V it is also possible to use 4-5 NiMH cells or 2 Li-Po cells, but then the device is uselessly bigger, heavier and more expensive. The solution is just the usage of a suitable step-up circuit. LT1304 from Linear Technology belongs to “MicroPower” DC/DC step-up circuits operating already from a very small voltage, 1.5V typically.
Thanks to a very low power consumption (10uA/Shutdown) and a built-in independent low battery detector, it is optimized for usage with batteries. LT1304 needs for its operation only a few external components – 2 capacitors, 1 inductor and 1 diode is all that is necessary to create an operating DC/DC circuit.
LT1304 is available in 3 versions – LT1304VCS8-5, LT1304CS8-3,3 with fixed voltages and LT1304CS8 with adjustable output. Versions with fixed output voltages don´t need a divider in a feedback, what further simplifies a circuit.