[Move]: 0.4 V supply voltage cmos circuit to control the duty cycle of square wave...

[Debasish_Halder]

Friends I need a 0.4 V supply voltage cmos circuit to control the duty cycle of square wave...
I have a perfect square of 50% duty cycle with 0.4 V amplitude 150Hz frequency.I want to control the duty cycle from 0-50% by keeping the frequency same....kindly tell me how can I do that...

 

[erikl]

Why would you need a 0.4V supply voltage to change the duty cycle of a 0.4V square wave? Could you explain?

 

[BradtheRad]

I was ready to suggest a capacitor-resistor-diode arrangement, to modify the waveforms.

However a diode does not act below 0.4 V. This appears to be an exercise in thinking up ways to do the job without using a diode.

 

[Debasish_Halder]

Why would you need a 0.4V supply voltage to change the duty cycle of a 0.4V square wave? Could you explain?

Sir it could be used in brain pacemakers which could be used in DBS...

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Friends, can I use PWM for this purpose??? kindly suggest me some voltage controlled PWM which could work at 0.4 V supply voltage.......

 

[BradtheRad]

There are low-barrier diodes (shottky, germanium) which may operate below 0.4 V.

If you bias a JFET to just the right degree, you may get it to modify your waveform.