12v to 5v converter
12v to 5v converter
(OP)
if i have a 12v battery and require +5 and +12volts input, how would i go about doing this?
thanks for the help
thanks for the help
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RE: 12v to 5v converter
RE: 12v to 5v converter
this is the data sheet for the module im trying to run
http://partner.advantech.com.tw/epartner/Files/Temp/PCM-3345.pdf
RE: 12v to 5v converter
RE: 12v to 5v converter
RE: 12v to 5v converter
RE: 12v to 5v converter
<nbucska@pcperipherals.com>
RE: 12v to 5v converter
RE: 12v to 5v converter
Consider a two-stage supply. Use a switcher to knock the +12V down to something close to +5V, the follow that with a LowDropOut linear. That is, if you have the board space. This is how I'm doing it in the Datalogger project.
This will get you the cleanest and most efficient +5V. If you don't mind the heat and current draw, just do the linear - 3 parts : regulator and two caps. But it can get bloody hot dropping 12 down to 5 with any kind of real current.
A switcher is a few more parts. Regulator, 3 caps, an inductor and a diode. Then again, these can all be SMD devices ...
National has a great power supply generator on their site. Feed it all the parameters, and it spits out a circuit that it can simulate. They'll even build a sample and send it to you :) All SMD and tiny.
Dean.
RE: 12v to 5v converter
RE: 12v to 5v converter
The document talk about a +/- 5 V and 12 V connector, but do you need all foúr voltages ?
-5 V and/or -12 V are usually used for RS-232 only, but ... ?
You will need a switcher or an additional battery in order to get the negative voltages.
These seldomly pull more than 150 mA, however.
What kind of requirement do you have for the +12 V ?
If your battery is of the lead-acid type the voltage from it will drop from about
13.8 V to well below 11 V during its discharge from full to nearly flat.
The discharge curve is thus quite steep as compared to Ni-Cd and Ni-MH batteries.
RE: 12v to 5v converter
as for the +12v it needs bout 100mA
hmmm so i need to regulate the +12v too eh
RE: 12v to 5v converter
But aren't linears MUCH more robust than switchers?
not switchers built for power.
use caps with a low virtual series resistance and you can add capacitance, but check the datasheets and be carefull.
for the +12 just use a linear it is much simpler.
RE: 12v to 5v converter
RE: 12v to 5v converter
by the way la_mer, floppies and hard drives create pretty substantual current spikes, keep this in mind in your power supply design.
48 volts to 12,5,-5,-12 a switcher was the only option once the stupid sales engeneer said the existing product we made could be retrofitted into there old systems. The heat would have been to much especialy in that sardine can.
RE: 12v to 5v converter