Device for measuring the ionization current in a radiofrequency ignition system for an internal combustion engine

A device for radiofrequency ignition of an internal combustion engine including a power supply circuit including a transformer, a secondary winding of which is connected to at least one resonator that has a resonant frequency in excess of 1 MHz, and two electrodes configured to generate a spark to initiate combustion of a combustible mixture in a cylinder of the engine in response to an ignition command, the device comprising:

• a measuring capacitor connected in series between the secondary winding of the transformer and the resonator;
• a circuit for measuring a current at terminals of the measuring capacitor, the current providing an electrical image of a trend of the combustion;
• and
• a protection circuit, connected between the measuring capacitor and the measurement circuit, the protection circuit comprising a diode bridge polarized by resistances at a power supply voltage that is proportional to a polarization voltage applied between an electrode of the resonator and an engine ground, and the protection circuit maintains a low desaturation time for measurement of the current.