Best way to step down 12V dc and 24V dc to 5v dc for microcontroller

Thread Starter

JDR04

Joined May 5, 2011
367
Ambiguity reigns supreme! You should try to be more precise about your requirements.
Hi Papabravo, I would like to to use a microcontroller to blink a couple of 12V lights on my car and then a truck I have. Car is 12Vdc and truck is 24V dc. Hope that clears it up?? Hence using a microcontroller will be the easiest for me but will need to be powered.
 

Ian0

Joined Aug 7, 2020
5,889
Hi Papabravo, I would like to to use a microcontroller to blink a couple of 12V lights on my car and then a truck I have. Car is 12Vdc and truck is 24V dc. Hope that clears it up?? Hence using a microcontroller will be the easiest for me but will need to be powered.
Are you powering JUST the microcontroller, or other items such as relays?
A microcontroller will only need about 5mA, so use a 7805.
 

LowQCab

Joined Nov 6, 2012
2,342
Why use a Micro-Controller to "Flash Lights" ?
A 555-Timer-Chip paired with a MOSFET can't be beat for simplicity,
and only need a Zener-Diode for a "Power-Supply", (only required on the 24-Volt system).
( unless, of course, you're wanting to get some practice with learning to write Code )
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bassbindevil

Joined Jan 23, 2014
505
If "off the shelf" is a good thing, there are car USB and phone chargers rated for 24V that output 5V at 1 amp. Most will have a common converter chip like the MC34063 inside.
 
Hi, what would be the best way to step down 12V dc and 24Vdc to 5Vdc for a microcontroller please?
Use a Recom R-785.0-0.5 (6.5V to 32V input and good for voltage spikes in vehicles). Check output current (max 0.5A) and switching noise (may need a small LC if anything sensitive).
 

splud

Joined Jun 30, 2013
35
I'm with others on (switching) buck for efficiency, and linear if you're just powering the micro itself. You should mind that if you're running off a non-ignition switched source, your circuit will be a burden 24/7, so efficency (and making use of µC sleep modes) would be very important.

I note you have a wholly separate thread on manipulating the lights, and this could have just been folded into that.
 
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