how to keep the output amplitude of DIFFERENTIAL VCO CONSTANT

[pavan5720]

I am have a differential vco using ring osc ckt when the control voltage at the tail current source is changed the amplitude changes, is there any logic which can tweak it the normal amplitude , any reference shall be very helpful

 

[jiripolivka]

I am have a differential vco using ring osc ckt when the control voltage at the tail current source is changed the amplitude changes, is there any logic which can tweak it the normal amplitude , any reference shall be very helpful

Like in any other oscillator, a variable load is best used with a buffer amplifier. If you need a differential buffer, use two amplifiers. Frequency unknown, otherwise there are commercial ICs available.