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Design a 0.1uA supply independent current source

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haman1986

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Im going to design a 0.1uA supply independent cs
can anybody help me how can i do it?
i should simulate it in cadence software
 

Hi,

I think you can use a current mirror or similars.
200px-Simple_bipolar_mirror.svg.png

You can set the current with changing R value.
But you have to be carefull about one point. 2 transistors have to be same. Generally beta values can't be equal for same transistors. You can search current mirror ic or maybe you can find same transistor which beta values are same.
 

Hi,

use a 9V battery and a 90Mohms resistor.

If you are not satisfied with my solution: give more detailed specification.

Klaus
 

thanks for answer
this current source is a supply independent current mirror source whit a start up that i want to design whit mos transistor for integrated circuit
and with resistor less than 500kohms
Von for transistor 0.2v
 
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haman1986 said:
thanks for answer
this current source is a supply independent current mirror source whit a start up that i want to design whit mos transistor for integrated circuit
and with resistor less than 500kohms
Von for transistor 0.2v
Click to expand...

You can change bjt with mosfet transistors :)

Same as bjt, When you use mosfet, your VGS voltages will be same for 2 transistors. According to this choose same w/L ratio.

IDSQ = KN*(VGS-VTN)^2
 

haman1986 said:
this current source is a supply independent current mirror source whit a start up that i want to design whit mos transistor for integrated circuit
and with resistor less than 500kohms Von for transistor 0.2v
Click to expand...

For theoretical considerations and simplest circuit see this basic paper by Eric A. Vittoz: View attachment AnalogCircuitsInWeakInversion_EricVittoz.pdf, pp. 2 ff. of the PDF, and especially pp. 10 & 11 .

A further elaborated and more complex circuit you can find in this PDF (link).
The start-up circuit is at the right side of Fig. 1. (MB9 - MB13).
 
Hi,

you say nothing about supply voltage range and precision.
temperature drift?
It should be a DC source?... Without the need for calculating AC (varying supply voltage, varying load resistance...)


Klaus
 

haman1986 said:
Im going to design a 0.1uA supply independent cs
can anybody help me how can i do it?
i should simulate it in cadence software
Click to expand...

Never start a design problem without listing all constraints on all requirements for input, output, time&frequency domain and environment stress, accuracy and stability.

Then you can choose what suits the design, with CC FET or a CV bandgap and current mirror using a precision resistor.

how about a 0.1uA CC source at 1kV @ 1GHz? With no DC, @85C ... Catch my drift?
 

Hi,

He wants only 1 uA and i think temperature is not important. Also you are right i dont say anything about precision. This a basic source and he can start with it.

KlausST said:
Hi,

you say nothing about supply voltage range and precision.
temperature drift?
It should be a DC source?... Without the need for calculating AC (varying supply voltage, varying load resistance...)


Klaus
Click to expand...
 

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