Modulation Circuit and Method

A modulation circuit for modulating a wireless power transfer circuit,

• the modulation circuit having a switching circuit having a first state, a second state, and a third state,
• the modulation circuit having a modulation mode in which the first state defines a normal state and the second state defines an operative state,
• wherein in the operative state, the modulation circuit is configured to modulate an electrical parameter of the wireless power transfer circuit in a modulation direction,
• the modulation circuit further configured to apply a trial modulation to the electrical parameter to determine whether the modulation direction matches a desired modulation direction, and
• the modulation circuit further configured to apply a modulation translation responsive to the modulation direction differing from the desired modulation direction, the modulation translation changing the modulation mode by swapping the second and third states such that the third state defines the operative state.

A method of modulating a wireless power transfer circuit, the method including:

• modulating, in an operative state, an electrical parameter of the wireless power transfer circuit in a modulation direction;
• applying a trial modulation to the electrical parameter to determine whether the modulation direction matches a desired modulation direction;
• and
• applying a modulation translation responsive to the modulation direction differing from the desired modulation direction, the modulation translation causing the modulation direction to match the desired modulation direction.