Quality factor estimation of an inductive element

A wireless charger comprising:

• an antenna comprising an inductive element and a first capacitive element series-connected between a first node and a second node;
• and
• an electronic device comprising:
• a first metal-oxide-semiconductor (MOS) transistor connected between the first node and a third node configured to receive a reference potential, the second node being coupled directly or via a second MOS transistor to the third node;
• a second capacitive element connected between a fourth node and an interconnection node between the first capacitive element and the inductive element;
• a current generator configured to provide an alternating current (AC) current to the fourth node;
• and
• a switch connected between the fourth node and the third node.

A method of operating an electronic device, the electronic device comprising an inductive element and a first capacitive element series-connected between a first node and a second node, a first metal-oxide-semiconductor (MOS) transistor connected between the first node and a third node coupled to a reference potential, the second node being coupled directly or via a second MOS transistor to the third node, a second capacitive element connected between a fourth node and an interconnection node between the first capacitive element and the inductive element, and a switch connected between the fourth node and the third node, the method comprising:

• providing, by a current generator, an alternating current (AC) current to the fourth node;
• coupling the first and second nodes to the third node and opening the switch at a beginning of an estimation phase of a quality factor of the inductive element;
• measuring, during the estimation phase, a voltage of the interconnection node in response to the AC current having a frequency equal to a resonance frequency of the series-connected inductive element and first capacitive element;
• measuring the resonance frequency;
• and
• closing the switch at an end of the estimation phase.