In many cases can be very handy to be able to convert 1.5V to 5V. Then you can power microcontroller or LED from a single AA or AAA battery.step-up DC-DC converter that can convert voltages from 0.7V to any in range from 2V to 5.5V. MAX1676 have already preset pins for 3.3V and 5V, that makes easer integration in 3.3 and 5V circuits. IC can dissipate up to 444mW.
Lets say wee need to get maximum output current 300mA, then wee need to put some efforts. Because output power is 5Vï¿½0.3A=1.5W. Lets say efficiency is 100% then the power drawn from battery will be 1.5W too. At 1.5V voltage this will be 1A current. Not all batteries can drive such currents. Other important part is inductor. For this wee need inductor with high current saturation which usually leads to increase of size.
If current is over 300mA, then inductor inductance 47uH;
If current is over 120mA, then inductor inductance 22uH;
If current is over 70mA, then inductor inductance 10uH
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