Temperature-stable LC oscillators and methods of oscillation at temperature null phase

摘要

An LC oscillator tank that generates a tank oscillation at a phase substantially equal to a temperature null phase. The oscillator further includes frequency stabilizer circuitry coupled to the LC oscillator tank to cause the LC oscillator tank to operate at the temperature null phase. In one aspect of the disclosure, a feedback loop may split the output voltage of the LC tank into two voltages having different phases, where each voltage is independently transformed into a current through programmable transconductors, The two currents may be combined to form a resultant current which is then applied to the LC tank. The phase of the resultant current is such that the LC tank operates at an impedance condition that achieves frequency stability across temperature.

主权项

1. A method of operating a feedback oscillator circuit comprising an LC tank and an amplifier circuit coupled in a closed loop, the feedback oscillator circuit producing an output signal having a frequency of oscillation, the method comprising:
applying a first phase shift and a second phase shift to an output voltage of the LC tank to split the output voltage into a first voltage and a second voltage having different phases; converting the first voltage into a first current in accordance with a first programmable transconductance value; converting the second voltage into a second current in accordance with a second programmable transconductance value; combining the first and second currents to obtain a resultant current; and applying the resultant current to the LC tank.