# Who has the Knowledge? DC to DC Step down.

#### YeahSammyShoots

Joined Jan 3, 2021
2
My first post in forums and fairly new to electronics.... take it easy on me.

Im needing help determining what is the missing piece to this puzzle.

Im looking to power a cinema camera that is typically powered Via an AC adapter
The AC Adapter states "Output" is 15V 3A.

The battery I would like to use reads "24.22v 6.26A"

I know a buck converter can control my voltage output but what does that do to the current.

picture attached for a point of reference.

any help, knowledge or insight would greatly help.

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#### Papabravo

Joined Feb 24, 2006
16,165
The basic power converter equation you seek is summarized as:
Power out is always less than power in. Sometimes it will be much less.
Let's start with the output power: 15VDC @ 3A = 45 watts.
Assume for grins and giggles that the efficiency of the putative converter is 80%
The required input power would be 45 / 0.8 = 56.25 ≈ 57 watts
Now 57 watts / 24.22 VDC = 2.35 Amperes
So under these assumptions you have a shot at making a viable DC-Dc converter.
Just because you have a shot at it does not mean you can succeed.
Not everybody can successfully design and fabricate such a device the first time out of the box.
Best strategy for you is to purchase one that can meet the requirements.

#### YeahSammyShoots

Joined Jan 3, 2021
2
Thanks for your Info, I think it’s beyond me to design and build one at this time. I’ve looked online and can seem to find what I need in a small formfactor

#### dl324

Joined Mar 30, 2015
12,871
Welcome to AAC!
Im looking to power a cinema camera that is typically powered Via an AC adapter
The AC Adapter states "Output" is 15V 3A.
Adapters for devices are spec'ed for the maximum requirements of the device. The device will take what it needs. Just like the lamp that you plug into an outlet. The circuit would normally be rated for several times more current than the lamp needs and you never worry about limiting current to a lamp.
The battery I would like to use reads "24.22v 6.26A"
That doesn't look like a battery to me.
I know a buck converter can control my voltage output but what does that do to the current.
In addition to lowering the voltage, you also need to make sure it can handle the current.
fairly new to electronics.... take it easy on me
A word of advice. Don't use cartoons to discuss circuits. Block diagrams and schematics are preferred.