Low voltage inrush current limit
Low voltage inrush current limit
(OP)
Hello everyone. I have a circuit which runs at 5V, ~330mA usually. At turn-on I have a spike to above 2A for a short time (on the order of miliseconds, not sure right now exactly how long). I would like to limit this to < 1A. The circuit is supplied by USB, and as it is now it doesn't work on some computers. Others have no problems.
I have looked into thermistors commonly used as inrush current limiters, but what I have found seems to be too high resistance (I can't afford the voltage drop) or rated for too high current (doesn't get hot enough to reach lower resistance).
Any thoughts on what to do? Any other info needed?
Thanks in advance for your help.
I have looked into thermistors commonly used as inrush current limiters, but what I have found seems to be too high resistance (I can't afford the voltage drop) or rated for too high current (doesn't get hot enough to reach lower resistance).
Any thoughts on what to do? Any other info needed?
Thanks in advance for your help.





RE: Low voltage inrush current limit
TTFN
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RE: Low voltage inrush current limit
There could be a redesign in the future, but how would you "design out the surge"? I thought that a common way of doing this is with PTC thermistors.
RE: Low voltage inrush current limit
I could see how a thermistor could work, but then you'd need something that would bypass it, once everything is powered up, otherwise, you'd lose a substantial amount of supply voltage across the thermistor under normal operating conditions.
TTFN
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RE: Low voltage inrush current limit
Keith Cress
kcress - http://www.flaminsystems.com
RE: Low voltage inrush current limit
IRstuff, the voltage drop under normal conditions is exactly the problem with all the thermistors I've found.
RE: Low voltage inrush current limit
http://w
Glenn
RE: Low voltage inrush current limit