Pololu 5V, 2.5A Step-Down Voltage Regulator D24V25F5 (POLOLU-2850)

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This small synchronous switching step-down (or buck) regulator takes an input voltage of up to 38 V and efficiently reduces it to 5 V. The board measures only 0.7″ × 0.7″, but it allows a typical continuous output current of up to 2.5 A. Typical efficiencies of 85% to 95% make this regulator well suited for powering moderate loads like sensors or small motors. High efficiencies are maintained at light loads by dynamically changing the switching frequency, and an optional shutdown pin enables a low-power state with a current draw of a few hundred microamps.

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Hi, will this work in converting a 24v power source to power a raspberry pi 4? Thanks.

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Hi Tom,

Welcome to the forum!

The Pololu regulator should work if your 24 V input is DC, it’s quoted to be able to deliver 5V which is the operating voltage of the Pi boards.
The reason that all of the Pi PSU’s output 5.1V is to ensure that the CPU is not limited by the lower voltage (called voltage droop when high current is drawn).

Personally I would go with this regulator as the features offer slightly more protection to the Pi in the form of thermal protection(to ensure that it is able to maintain its full current output a heatsink might be necessary) in comparison to CE05572.


I would also have a look at the higher rated regulator here which is capable of outputting 5A.
The Official Pi PSU outputs 3A.

i noted that even with the 2200 over clock at 5.25 volts it never drew over 2A…some food for thought…!1!

if your running spinners then you will need the full 3A unit as Liam described ,and or a powered usb 3 hub …,i was using a wd green M-2 and a usb sata bridge, and a sandisk 64 gig usb stick as well…kb and mouse from the usb ports
also if your using/drawing current from gpios there are another factor to feed into the equation
current is everything…voltage is important also but if you keep the distance of the power wires short like les than 5Cm and use 16-18-20 gauge wiring beteen the reg and therpi-4 then you should be ok with this regulator…keep an eye on your current draw… you may need to fit a sink on the reg a small tiny one from core as used in the 3 pack alloy sink pack… with no problems,

and cut some of this stick it to the under side of the board same size as the bottom then place one of the sinks from the 3 pack and it will upgrade its current capabilities,

i am assuming that if your powering the rpi-4 from the gpios i am told that you are by-passing the power protection cct…something to be aware of…
i`d just buy a usb-c cable and hack it to adapt to the rpi…keep the wires short and it will work ok…

P.SS…if your running headless then also the rpi-4 will draw less current also…

Thanks heaps, Liam and Brian!
I think I’ll get the 5A reg and some heatsinks.
I’ll be using the Pi to run Klipper for a 3D printer.


the 5A amp version does not require any heat sinking…its just a pity they made the other 2.5 amp but it will run the rpi in most cases as long as your not heavy loading the usb ports…they should have made an 3 amp version to be inline with rpi specs …

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Hey Brian,

I agree, in most situations you’re probably not going to need a heatsink for a board with that rating. However, they still have some losses and we’re talking about a pretty substantial difference in voltage (relatively speaking). Since we’re not sure about the environment the board will be exposed to it may not be a bad idea to add a heatsink anyway as there will certainly be at least some heating from the converter particularly if you’re drawing current to the peripherals of the Pi, and it won’t cause any issues by adding it. All the best with the project Tom!