Constant Current Source (undepend of Load)

Prodigy 40 points

Other Parts Discussed in Thread: TPS75100, LM317A

Hello,

please help me to build Constant Current Source circuit:

Parametrs:

Vin = 40VDC

Rload change: from 20 to 40 Ohm

Iout constant = 1 A (and don't depending on load)

Best Regards

Dima

over 9 years ago

0 GJ over 9 years ago

TI__Intellectual 1106 points

Hi Dima,
you will need to look at the thermal aspect if you are planning to use a linear regulator.
you could use the circuit in the blog as reference:
e2e.ti.com/.../flashback-design-create-a-simple-led-driver

regards,
GJ

0 DK over 9 years ago in reply to GJ

Prodigy 40 points

you can offer another solution? It is important that the load changes and the current must be constant, Current does not depend on the load

0 Ryan Eslinger over 9 years ago in reply to DK

TI__Guru 55940 points

Hi Dima,

Unfortunately traditional LDOs are not really set up for your type of application. They regulate voltage, so by Ohm's law, when the resistance changes, the current will change. I believe you need something more like TPS75100 which unfortunately does not meet your current requirements.

Very Respectfully,
Ryan

0 Ryan Eslinger over 9 years ago in reply to Ryan Eslinger

TI__Guru 55940 points

Hi Dima,

After reading more about GJ's suggestion, I believe he actually was pointing you to a good device for your application.

Please see the following excerpt from the LM317A datasheet:

Very Respectfully,

Ryan

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Constant Current Source (undepend of Load)