# Max input current of DC DC converter

I'm not sure if this is the right place to ask this kind of question(mine seems practical as opposed to academic) but here it goes.

The embedded board I am using(Jetson TX1) can be powered using:

• 4S LiPO(4 cell / 14.8V nominal / 16.8V charged) with 1-2A (or 15W) of continuous current
or
• 3S LiPO (11.1V nominal / 12.6 charged / 9V discharged) with 1-2A (or 15W) of continuous current

I'm trying to mount Jetson TX1 on my quadrocopter which has XT30/XT60 ports with the following spec:

• Output Voltage: 20 - 26.1 V
• Max Continuous Output Current: 10 A

Now I'm trying to buy a DC-DC step down converter and I'm currently looking at DROK 200143 DC-DC Buck Converter 3.5-30V to 0.8-29V 10A Step-down Volt Adjustable Output Regulator Module Power Supply which has

• 3.5-30V input
• 0.8-29V output output
• 10A Max output current

My concern is the input current. The output current only needs to be 2A but it should take 10A input current.

Is the max input current same as the max output current?

• Just because your source can deliver 10A it doesn't mean your regulator has to draw 10A. If you use the regulator to drop the voltage, then it will draw less current than it puts out. So, for a 2A output it will draw a little less than 2A from the battery. You must match the input voltage range, but current is different.
– JRE
Commented Dec 6, 2016 at 6:21
• 10A max current is the current it can support on that rail. Based on Load actual current varies. Use following eqn Input power * efficiency = Output power to calculate input current. It doesn't require to handle 10A input current, Based on load requirement current varies Commented Dec 6, 2016 at 6:22