Current limit for 5V @ 120mA

Allenlsk · Jul 26, 2017

Hi,

I am working on something that can limit the current draw from a 5V source with current of 500mA. But I wanted to limit the current draw to only 120mA.

May i know how should I do that, or is there a standard IC that can do it, I try to search for current limit IC but can not find one that is giving 5V @ 120 mA

Please help

Minder · Jul 26, 2017

LM317 can be used as a current regulator, there should be alot of examples out there.
M.

BobK · Jul 27, 2017

Please explain further what you are trying to do. If you intend to hook up a device that requires 120mA at 5V, you can connect it directly to a 5v, 500mA supply. It will use only the current it needs.

The rule for power supplies is that they must provide the correct voltage and at least the required current. In fact, you should normally allow a margin for the current, never run a power supply at the maximum current, or it will likely fail early.

If, on the other hand, what you want is something will set the voltage to whatever it takes to push 120mA into the load, you need a constant current source, as Minder said.

Bob

Audioguru · Jul 27, 2017

For an LM317 to produce an output limited to 120mA at +5V then its input must be at least +6.75V.

davenn · Jul 27, 2017

what Bob said ......

BobK said:

Please explain further what you are trying to do. If you intend to hook up a device that requires 120mA at 5V, you can connect it directly to a 5v, 500mA supply. It will use only the current it needs.
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Current limit for 5V @ 120mA

Allenlsk

Minder

BobK

Audioguru

davenn Moderator

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