Electronic – Limiting output current of a Buck Converter

buckcurrent-limitingdc/dc converter

I am trying to power a 4S-ESC to drive a BLDC motor using a buck converter and 24V,10A SMPS. However, my buck converter can only handle 10 Amps of current (safely) at 15V through its output side. Therefore, I need to make sure that the output current should not go over 10A, even if I increase the throttle input to ESC. Also, I do not want to put a relay triggered by a current sensor, since that will shutdown the power supply to my motor, which is undesirable. Thus, I want to 'limit' (or 'saturate') the current at 10A.

Is there a way to achieve this without hacking the buck converter?

If there isn't, these are the details of my buck converter-

Description : Non-isolated adjustable synchronous buck module

Rated Power : 200 W

Input Voltage : 8-55V

Output Voltage : 1-36V

Output Current: 10A

Operating frequency:180 kHz

Buck Converter Controller IC datasheet (click here)

(for more details – click here )

I am also sharing some photos for the other components and their placement,

NCE8580
HY1707 FS320J04 G

EDIT :
Thank you everyone for your inputs.

The photographs are for reference only, the buck converter seen in the photo is an old one (fried it up sometime back). Also, just to make it clear, I don't want to 'cut-off' my power supply or make a 'constant current' buck. What I really want is to 'set' a max value of current for my buck so that 'no matter what' the load does not draw a higher value of current from it.

Looking to achieve exactly this (see video) for my own buck! Thanks!

Best Answer

You need to sense the current, one way of doing it is below circuit:

schematic

simulate this circuit – Schematic created using CircuitLab

Above circuit is a simple low-side current sensing overcurrent protection. LM358 is wired as a comparator, it can't measure very accurately because it's not a rail to rail op amp but for this purpose it's good enough.

V1 is our voltage reference, using ohm's law at 10A voltage drop on R1 is going to be 1V. once it's gets above that opamp will draw it's output to the positive rail activating transistor base and drawing mosfet gate low. it will oscillate and keep the output current at 10A.

You can adjust the current to a lower value by lowering the V1 voltage.

The circuit is just an example on how it's done, of course you can measure the current at high side of the circuit etc. but it gives you an idea.