Wide frequency range voltage controlled oscillators

A phase-locked loop (PLL) circuitry comprising:

• a current source;
• and
• transformer based voltage control oscillator (VCO) circuitry comprising:
• upper band circuitry comprising first oscillation circuitry, a first harmonic filter circuitry, and a first selection transistor coupled to the current source, the first harmonic filter circuitry is connected between the first oscillation circuitry, and the first selection transistor is configured to filter an output signal of the transformer based VCO circuitry;
• and
• lower band circuitry comprising second oscillation circuitry, a second harmonic filter circuitry, and a second selection transistor coupled to the current source, the second harmonic filter circuitry is connected between the second oscillation circuitry, and the second selection transistor and is configured to filter the output signal.

A method comprising:

• connecting, in a first mode, upper band circuitry of transformer based voltage controlled oscillator (VCO) circuitry to a current source via a first transistor of the upper band circuitry;
• filtering, in the first mode and via a second harmonic filter circuitry of lower band circuitry of the transformer based VCO circuitry, an output signal of the transformer based VCO circuitry by disconnecting the lower band circuitry from the current source via a second transistor of the lower band circuitry;
• connecting, in a second mode, the lower band circuitry to the current source via the second transistor;
• and
• filtering, in the second mode and via a first harmonic filter circuitry of the upper band circuitry, the output signal of the transformer based VCO circuitry by disconnecting the upper band circuitry from the current source via the first transistor.