Dynamic tuning in wireless energy transfer systems

A zero voltage switching device comprising:

• a switch comprising a first terminal, a second terminal, and a control terminal;
• a first comparator comprising a first-comparator output terminal and a first-comparator first input terminal electrically connected to the first terminal of the switch;
• a second comparator comprising a second-comparator output terminal, a second-comparator first input terminal electrically connected to a first reference voltage, and a second-comparator second input terminal electrically connected to the control terminal of the switch;
• and
• control circuitry coupled with the first-comparator output terminal and the second-comparator output terminal, the control circuitry comprising:
• a phase detection circuit coupled with the first-comparator output terminal and the second-comparator output terminal;
• an integrator circuit coupled with the phase detection circuit;
• a third comparator comprising a third-comparator output terminal, a third-comparator first input terminal electrically connected to the first terminal of the switch, and a third-comparator second input terminal coupled with the integrator circuit;
• a flip-flop comprising a reset terminal, a clock terminal electrically connected to the third-comparator output terminal, and an output terminal electrically connected to the control terminal of the switch;
• and
• a controller coupled with the reset terminal of the flip-flop and configured to provide a reset signal to the flip-flop, and
• wherein the control circuitry is configured to:
• determine a phase difference between a first-comparator output signal and a second-comparator output signal,
• generate a second reference voltage based the phase difference, and
• cause a control signal to be applied to the control terminal of the switch upon detecting that a voltage signal at one of the first terminal or second terminal of the switch has crossed a voltage value equal to the second reference voltage.