can you please give us some specifications for your oscillator. I would guess that it is a low frequency oscillator (some MHz).
Does your oscillator be temperature independant ?
With my design the problem is that it's very temperature dependent. For decreasing the frequency, I decrease the power of the oscillator which makes it temperature dependent. Now, I'm stuck with the problem at the moment.
Maybe has somebody a great idea and can post a picture or a link. It would be very helpful...
Your oscillator could not be temperature independent. The frequency is clearly dependent on the Vth of your MOS. The Vth will drift with temperature.
The only solution I know is using some voltage and/or current reference. But of course, that will increase your current consumption.
one suggestion i would give is to use RC in between one of the inverters. Be sure to pick 2 types of resistors (positive TC and negative TC) to cancel out the temperature coefficient. Although this is not completely temperature independent, it is a decent but not too complicated approach in my opinion.