19.5V Step-down 12V for RGB ?

Other Hardware LEDs and Multiplexing
1

Hello,

I have several rolls of 12V RGB LEDs, and I'm wondering about their power supply.
I read that these strips could ask quite a lot in Amperage, knowing that I'm currently only a 12V and 2A charger, I'm afraid I'm limited.

Currently, I have a jack plug connected to the +12V of the headband, and the 3 colors connected to the GND via 3 TIP120 controlled by the arduino to manage the colors.

I have not tested it myself, because I'm afraid to burn out my power supply, so I'd like your opinion on it.

being a computer scientist, I have many PC chargers, from 60/90 to some 120W, the problem is that most of them are 19.5V, is there a step-down to have 12V with several amps (4 or 5A) ? because either the switching power supplies on ebay/Aliexpress are around 15/20€, so if the Step-down is the same price I don't see any interest.

I'm ready to listen to your advice :slight_smile:

Edit : my schema is in PJ :slight_smile:

Best regards,
Thomas.

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2

TIP120
If you have them, use them - but don't buy any more.

3

Hello

runaway_pancake:
TIP120
If you have them, use them - but don't buy any more.

Hello,
Why ?

4

Superior performance - speed and high V_ce vs low on_resistance.
Darlingtons were useful in their day, but everyone should be using FETs.

If you have a stash of TIP120's or somebody is going to give them to you, might as well use them.
But if you haven't any then it's just as easy to buy "logic-level MOSFETs".

5

ho, I asked around and indeed, the MOSFETs seem to be better adapted now (I often see the IRF520 coming out).
Thank you very much for this information :slight_smile:

6

IRL520 , not IRF520 (big difference).
The IRL is "logic level", the IRF is not.

7

Plenty of buck converters on your favourite retail website, get them with 12V output.

Get one with a 5V output to power your Arduino instead of the 7805.

Buck converters essentially swap voltage for current, so lower voltage out mean lower current in. Not 100% efficient of course so not perfect.