An electronic ignition system for an internal combustion engine. The system includes a coil having a primary winding with a first terminal and a second terminal and a secondary winding connected to a spark plug. A high voltage switch is serially connected to the primary winding. A control terminal carries a control signal to control the opening or closing of the high voltage switch. A first switch is interposed between a battery voltage and the first terminal of the primary winding, a second switch is interposed between the first terminal of the primary winding and a reference voltage, a third switch is interposed between the second terminal of the primary winding and said reference voltage. A driving unit is configured to generate signals to control the switches during a charging phase, during a transfer of energy phase, and during a measure phase of ionization current.