simple 150uA constant current supply

Dave · 2008-03-30T19:49:36+00:00

I would like to find the simplest way to provide a constant current of around 150uA (+/-20%) at around 2V.This needs to be discrete components rather than IC and should not involve pulse width modulation.The simplest form I thought of was a 3v voltage reg with a 20K resistor between it's 'reference ground' and the output but this seems clumsy.Anyone ?ThanksDave

Mar 30, 2008 81 Replies

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James Arthur 18 years ago

[snip SWCIII ckt]

For improved temp. stability just compensate Q2's Vbe:

Vcc -+- | +------------. | | [D2] [1.5k] | | [68k] +---. | |

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Paul E. Schoen 18 years ago

That is much better, about 0.48%/Degree C. I didn't know about the .STEP directive. This info may come in handy. I think the OP has left the building, but I have gained useful information.

Thanks!

Paul

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