How to control the input current of buck converter?

Thread Starter

Deepak Kumar 9

Joined Sep 8, 2017
Please tell me how the source current of the buck converter can be controlled using PID (proportional-integral-derivative) controller?
I want to know the closed-loop design for the input current controller of the buck converter.


Joined Feb 24, 2006
I'm not familiar with any reason why you might want to do this. You need excess current on the input to deal with load transients on the output. Limiting the input current would be like tying one hand behind your back as a professional street fighter.


Joined Oct 7, 2019
It is not uncommon to have several control loops.
In the picture above you can see "FB" which sets the output voltage. For battery chargers it is common to watch the current in D1 or L1 or at "vout" to limit the battery charge current. (keep the battery from over heating) When the battery voltage is low this might be the control loop. As the battery voltage climes the voltage feed back loop will take over.
You could measure the current at "vin" and add that into the controller. This is unusual but works if the "source" has limited power.
Any one of the three loops or a combination of all three will function at one time.