Mode select for multi-frequency oscillators

A system comprising:

• a resonator circuit including an input and an output, the resonator circuit configured to resonate at a fundamental frequency and a different, non-fundamental frequency;
• a startup circuit electrically coupled to the input, the startup circuit configured to generate a signal at about the non-fundamental frequency and detect when the resonator circuit is resonating at the non-fundamental frequency;
• an oscillator driver circuit electrically coupled to the output, the oscillator driver circuit configured to amplify and buffer the output of resonator circuit;
• and
• a load coupled to the oscillator driver circuit, the load including electric components that operate at the fundamental frequency and at the non-fundamental frequency, wherein the resonator circuit includes at least one of multiple physical resonators electrically coupled in parallel to each other or a single physical resonator that resonates at the fundamental frequency and the non-fundamental frequency.

A method of multi-frequency oscillator control, the method comprising:

• generating, by a startup circuit electrically coupled to a resonator circuit configured to resonate at a fundamental frequency and a different, non-fundamental frequency, a signal at about the non-fundamental frequency;
• detecting, by the resonator circuit, whether the resonator is resonating at the non-fundamental frequency;
• and
• amplifying and buffering, by an oscillator driver circuit electrically coupled to the resonator circuit, output of resonator circuit responsive to detecting the resonator is resonating at the non-fundamental frequency, wherein the resonator circuit includes at least one of multiple physical resonators electrically coupled in parallel to each other or a single physical resonator that resonates at the fundamental frequency and the non-fundamental frequency.