charge and discharge capacitor linearly CMOS circuit needed

[E-goe]

Hi

I need a simple CMOS circuit to charge and discharge a capacitor in a linearly way. The capacitor discharge rate should be 2 times longer as the charge rate of the capacitor.

I'm trying to do this with an simple CMOS invertor but I am unable to tune the discharge rate (2 times the charge rate).

Any ideas?It needs to be implemented with CMOS.
I also thought of implementing it with 2 current sources. But the problem is that I dont know where to put the charging capacitor in order to charge and afterwards discharge the capacitor with 2 times less current.


Greetz E-goe

 

[bastos4321]

Re: charge and discharge capacitor linearly CMOS circuit nee

Use an nmos current source in series with a pmos current source. One of the current sources has twice the current. Insert in series with the current sources an inverter connected to the capacitor.

Bastos

 

[E-goe]

Re: charge and discharge capacitor linearly CMOS circuit nee

Hi Bastos4321

Can you add a schematic because I dont know what you mean by putting the current sources in series.

Thankd in advance

Greetz E-goe