Current Limiting/Control

[SkrillBill]

Hello,
i'm in the process of designing and building a power supply for my workbench. For details on that project, refer this thread.

In that build im using a few LM-series regulators to control voltage. Maximum output will is planned to be 1A, but realistically 500mA is a closer goal. At this time im not sure about variable current, but i do want to limit the current to keep the magic smoke inside the components.

How would i go about limiting current with a fixed voltage from the regulator without inducing more strain than necessary? Would i limit it before or after the regulators? And, should i worry about having a constant current of some kind (via a choke i think?)?

This is all new to me, and i'm not 100% sure how current control or limiting works or what i need to make it work. The more in depth the explanation the better, i want to understand the concept not be told "do this with this and it will work".

Many thanks!

[danadak]

Google "current limit circuits power supply", quite a few hits, but many circuits
fairly simple.


Normally limit is placed after voltage source. Its done by sensing load current
and using that in a feedback loop, sometimes as simple as a transistor, a couple
of diodes, and a rsense. Other better aopproaches for greater range and accuracy
using an OpAmp.

There are some circuits that foldback the current.





Regards, Dana.