Resonant wireless power transmitter circuit and control method thereof

A phase detection and control circuit, configured to operably control a resonant wireless power transmitter circuit which comprises:

• a load circuit;
• and a power conversion circuit which is coupled between an input power supply and the load circuit, wherein the power conversion circuit is a half-bridge or a full bridge power conversion circuit, and includes a plurality of power switches and a current sensing device, wherein the plurality of power switches are configured to operably switch with an operating frequency to convert the input power supply to an output power for driving the load circuit such that the load circuit has a load current, wherein there is a load current phase difference between the load current and the operating frequency;
• wherein the phase detection and control circuit detects a voltage difference between the current inflow terminal and the current outflow terminal of the current sensing device within a dead time period in which each of the plurality of power switches are OFF, wherein the voltage difference corresponds to the load current phase difference;
• the phase detection and control circuit including:
• a phase difference determining circuit which includes a comparison circuit and a detection timing circuit, wherein the comparison circuit compares the voltage difference and a reference voltage to generate a comparison result, and the detection timing circuit selectively latches the comparison result to generate a phase difference determining signal according to a pre-determined detection timing point, wherein the pre-determined detection timing point is a pre-determined time point within the dead time period;
• and
• a signal conversion circuit, including a logic circuit which generates the impedance control signal according to the phase difference determining signal and a time length signal.

A driving circuit, configured to operably drive a resonant wireless power transmitter circuit which comprises a load circuit;

• the driving circuit including:
• a power conversion circuit which is coupled between an input power supply and the load circuit, wherein the power conversion circuit is a half-bridge or a full bridge power conversion circuit, and includes a plurality of power switches and a current sensing device, wherein the plurality of power switches are configured to operably switch with an operating frequency to convert the input power supply to an output power for driving the load circuit such that the load circuit has a load current, wherein there is a load current phase difference between the load current and the operating frequency;
• and
• a phase detection and control circuit, configured to operably detect a voltage difference between the current inflow terminal and the current outflow terminal of the current sensing device within a dead time period in which each of the plurality of power switches are OFF, wherein the voltage difference corresponds to the load current phase difference.

A method for controlling a resonant wireless power transmitter circuit which comprises:

• a load circuit;
• and a power conversion circuit which is coupled between an input power supply and the load circuit, wherein the power conversion circuit is a half-bridge or a full bridge power conversion circuit, and includes a plurality of power switches and a current sensing device, wherein the plurality of power switches are configured to operably switch with an operating frequency to convert the input power supply to an output power for driving the load circuit such that the load circuit has a load current, wherein there is a load current phase difference between the load current and the operating frequency;
• the control method including:
• determining a dead time period in which each of the plurality of power switches are OFF;
• and
• detecting a voltage difference between the current inflow terminal and the current outflow terminal of the current sensing device within the dead time period, wherein the voltage difference corresponds to the load current phase difference.