24V led driver - powersource for ESP32 question?

[MisterD]

Hi,

I'm in the proces of making a led light/chandelier using 24V ledstrips and ESP32 running WLED (or ESP32-C6 running custom code using zigbee, not sure yet).
I will be using 3 or 4 strips of 1meter ledstrips at 9W max/meter. So about 30 to 40watts max power requirements. I have bought a 220V AC to 24V DC 60W constant voltage LED driver powersupply, which should be enough I believe.

To be able to dim the leds I'm using a simple mosfet board, which can throttle the output to the LEDs using an ESP32 pin and PWM. I tested the setup and everything works like expected.

Now my question: is it a good idea to power the ESP32 from the 24V LED driver? I've put a buck converter in between to convert the 24V to 5V and this works.
I'm not sure however if having the LED driver on all the time is a good idea since 95% of the time the lights will be off. Since the ESP32 will only consume about 150mA or something like that?

Or should I provide a dedicated 220V AC to 5V DC adapter (that can provide 500mA for example) to power the ESP32, and use a relay board to switch the LED driver on or off using an additional ESP32 GPIO Pin?

Kind regards

[PlainName]

Why not use both the LED supply and a separate USB-C input? The end user has the choice, then, of a simple and single supply (the LEDs) or another cable but low power when 'off' (USB).

If you wanted to get really clever you could have a battery, charged from whatever source is available, to cover those times when the user is dicking about swapping cables and stuff, or the cleaners remove the plug labelled "DO NOT TURN OFF".

[MisterD]

I've read your answer a couple of times but I don't really understand what you mean (non native english speaker here).

What I want to make is a LED chandelier to hang from the ceiling, so the power supply/supplies, ESP32, mosfetboard,... would all be integrated into it.

[PlainName]

Sorry, I may have misunderstood. It seemed to me that you are asking which of two choices to go with to power the ESP32 and related electronics:

1. The 24VDC LED driver, reduced to 5V by a buck converter.

or

2. A 220V AC to 5V adapter (what we would call a wallwart, presumably).

So my suggestion is: use both. You would arrange so that the 24VDC buck would normally provide the 5V power, but if the 220V adapter is plugged in it cuts off the 5V from the 24VDC supply. A MOSFET would do the trick. That way you don't have to decide now but can choose when you hang the light.

Even if you later decide that you will never use one of the other, you just don't populate the PCB with the components for that part. It costs almost nothing to design it in and then not use it, but if it's not there you can't later decide you did want it after all.

The bit about the battery you can safely ignore - just a bit of light-hearted banter.

[tooki]

Regardless of whether you use a buck converter from the 24V or a separate supply: why use 5V? ESP32’s are all natively 3.3V, so using the 5V input pin you’re simply feeding into a 3.3V LDO that burns off the excess 1.7V as heat. So unless you want to power it from USB, it’s smarter to just use a 3.3V buck converter or supply, onto the 3.3V pin of the ESP32 module.

[liaifat85]

Using a separate 220V AC to 5V DC adapter to power the ESP32 will be efficient. This way, you can turn off the LED driver completely when the lights are not in use, thus saving power. You can use a relay to turn the LED driver on or off based on when the lights are required.

[Smokey]

If the LEDs are the RGB addressable ones, they need a minimum of about 3.7V.  I know they advertise some of those strings as "12V" or "24V" but anything more than the 3.7V that they just PWM away internally.  If you start with 5V, boost it to 24V, and then have the LEDs internally PWM that back to 3.7V, that seems pretty inefficient. 
Use the LEDs that run at a lower voltage and you don't have the crazy power supply requirement.