3.7v Li-PO to 3.3v and 5v simultaneously

Hello, I am working with a group to design an electronic payload for a rocket, and we want to have 3.3v and 5v available for different devices. So the problem is finding a booster that will go from a 3.7v Li-PO to 3.3v and 5v simultaneously. Everything I have found so far just does one or the other.

colecago over 13 years ago

So use two different devices. Use a boost convertor from 3.7V to 5V and a standard voltage (linear) regulator to go from 5V to 3.3V. You can get devices that do both it basically uses double the circuitry so its like having two different ones. And the reason to use the regulator on the 5V line is because of the sag of the battery. Linear regulators need the input voltage to be higher than the output by a certain amount, its called the dropout voltage and you don't have much room between 3.7V and 3.3V even before the battery drains.
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benheck over 13 years ago

Yes most devices have multiple voltages in them, one way or another.

For efficieny, look for "switching regulators". Harder to wire up than linear regulators, but batteries last longer.
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Former Member over 13 years ago in reply to benheck

Battery life isn't a big consern. The device should be turned on for less than 1hour at a time and shouldn't draw that much power.
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