Hey Electronics folks, i need some help with a project that i’m working on.
I have a 12v lamp switch (possibly more being added soon) that i need powered by USB if possible.
I have basic electronics knowledge and several components at home that i could use to build a step up(?), i just don’t know the best or safest place to start.
Can anyone recommend what i should do, or scare me away from trying?
Thanks!
Mark
Making one is doable but not simple. Buying one is a easier solution.
I have used these a number of times:
and you have a nice selection possible from Mouser:
http://www.mouser.com/Power/DC-DC-Converters/_/N-brvxeZscv7?P=1yx5k7vZ1z0wuktZ1yxt7ff&Ns=Pricing|0
For a one off project, I would just buy a commercial DC voltage converter and be done with it rather than building you own.
Keep in mind the USB is limited in the current it can supply. USB 1.0 and 2.0 limit is 0.5 amps (500 milliamps). At 5 volts that’d be only 2.5 watts. At 12 volts that would be only about 0.2 amps (assuming zero loss in your voltage conversion, more like 0.18 amps assuming 90% efficiency).
Dedicated USB charger limit is 3x that, but still quite low.
USB 3.0 can supply more, but only if your circuit is smart enough to tell the USB port it supports it.
Making one, which is not the recommended option here, goes something like this:
Select L and C with carefully selected resonant frequency.
Pulse the LC tank with harmonics that will make it resonate.
Take the output, smooth the ripple.
Ensure that current out can supply your needs. Remember that there is no way to create power, but you can increase voltage level.
Run weeks to months of spice simulations. Ensure all board traces and junctions can supply adequate current.
Easy 123.
Not.
They do make IC’s that can shortcut that process
LM 2622 step up converter