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Design >> Analog Design >> 10 mA constant current source
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Message started by umesh on Jul 24^th, 2016, 9:06pm

Title: 10 mA constant current source
Post by umesh on Jul 24^th, 2016, 9:06pm

Hi
I want to design constant current source of 10mA. My load will vary from 10 ohms to 5K ohms. I tried using current mirror circuit, but i am unable to achieve 10mA. Current mirror gives only 2mA constant current. Please suggest me another circuit which gives me 10mA constant current source. I have tried another circuit using op-Amp but it gives the constant current of 10mA up to 1.4k load range.

Title: Re: 10 mA constant current source
Post by vroy_92 on Jul 25^th, 2016, 12:02am

"Current mirror gives only 2mA of current".. What is limiting your current mirror from giving more than 2mA of current?

Title: Re: 10 mA constant current source
Post by umesh on Jul 25^th, 2016, 2:21am

when i tried to increase current capacity then it fails to reflect the current at output side.

Title: Re: 10 mA constant current source
Post by AnalogDE on Jul 26^th, 2016, 12:38am

Have you tried upsizing your current mirror by 5x?

Title: Re: 10 mA constant current source
Post by umesh on Jul 26^th, 2016, 1:52am

No i haven't tried that...I have no idea about it. Please let me know how to do this.

Thanks

Title: Re: 10 mA constant current source
Post by umesh on Jul 26^th, 2016, 2:27am

And if I do this then how to collect the x5 current ?
I want to flow 10mA current from load (10ohm to 5kohm).

Please give me brief idea how to do.

Title: Re: 10 mA constant current source
Post by Mos on Aug 29^th, 2016, 2:18pm

What are your supplies?
10 to 5k seems too large of variations(0.1V to 50V?)