Patent ID: 8022778

Claim:
An oscillator comprising: a tank circuit; a plurality of cross-coupled transistor pairs connected to the tank circuit; a current source connected to the plurality of cross-coupled transistor pairs; at least one switch connected to the plurality of cross-coupled transistor pairs, wherein the switch is adapted to activate a subset of the plurality of cross-coupled transistor pairs and to deactivate another subset of the plurality of cross-coupled transistor pairs to operate the tank circuit in the oscillator using the activated subset of the plurality of cross-coupled transistor pairs; wherein the current source comprises: a bias current input; and a current mirror connected to the bias current input, the current mirror comprising a diode-connected transistor connected to the bias current input, and a main transistor connected to the diode-connected transistor and to the plurality of cross-coupled transistor pairs; wherein the diode-connected transistor in the current mirror comprises a plurality of diode-connected transistors, each switchably connected to the bias current input.