LM2577: current limiter

Marco Trapanese wrote in news:i7nlhn$mr$ snipped-for-privacy@tdi.cu.mi.it:

Il 26/09/2010 19:46, Hammy ha scritto:

As I can see, the overcurrent protection is built-in. I can't change it, can I?

Marco

Marco Trapanese wrote in news:i7o1tv$b4b$ snipped-for-privacy@tdi.cu.mi.it:

Nope sorry just had a quick look.

You can try Murata to see if they have a small module that can fit your exsisting footprint and specs like these.

If it is just a few you can make your own like the one above useing one of the numerous boost controllers out there that has built in current limiting.

Another simple hystertic controller

How about adding your own current limiting cct. It can tap into the voltage feedback. When current limit is reached it increaces the voltage at the fedback pin to the lm2577(maybe via a diode) The 2577 then "thinks" the output voltage is to high and it reduces accordingly. Might not be the best solution in the world , but is an easy after fit , and it does work. Rob

neddie wrote in news: snipped-for-privacy@t20g2000yqa.googlegroups.co m:

Good idea.

There's high-side current monitor chips that can do that almost directly (tie into the FB node as Neddie suggested). Some can have the sense resistor float dozens of volts above ground. I have done stuff like that many times, where 3-4 things tied into the FB node. Voltage, current, temperature, dance contest results, and whatnot.

Il 28/09/2010 13:26, neddie ha scritto:

Yes, I will do that if I don't find a suitable device. The problem is the space... I don't have much on the board.

Marco

ZXCT1009 come to mind. Small sot 23 package.