Gate drive circuit

A gate drive circuit comprising:

• a first electromagnetic resonant coupler that isolatedly transmits a first radio-frequency wave from a primary side of the gate drive circuit to a secondary side of the gate drive circuit, and isolatedly transmits a reflected signal from the secondary side to the primary side, the primary side and the secondary side isolated from each other, the reflected signal generated by reflecting the first radio-frequency wave on the secondary side;
• a modulator circuit that modulates a second radio-frequency wave with an input signal to generate the transmission signal and outputs the transmission signal to the second electromagnetic resonant coupler, the modulator circuit disposed on the primary side;
• a second electromagnetic resonant coupler that isolatedly transmits a transmission signal from the primary side to the secondary side;
• a demodulator circuit that demodulates the transmission signal input from the second electromagnetic resonant coupler to generate an output signal, the demodulator circuit disposed on the secondary side;
• a variable capacitance diode into which the first radio-frequency wave is input from the first electromagnetic resonant coupler, the variable capacitance diode disposed on the secondary side, the variable capacitance diode allowing a capacitance thereof to vary according to a monitor signal;
• and
• a reflected signal rectifier circuit that rectifies the reflected signal input from the first electromagnetic resonant coupler to generate a monitor output signal, the reflected signal rectifier circuit disposed on the primary side.