Electronic ignition system with restriction of the voltage at a connection of the ignition coils primary winding

摘要

The electronic ignition device (50) comprises: an ignition coil (2) having a primary winding terminal (5) and a secondary winding terminal (6) generating a spark; a power element (3) arranged between the primary winding terminal (5) and ground (GND); a protection circuit (11) issuing a disable signal to the control terminal (8) of the power element (3) in preset conditions; and a voltage limiting circuit (51) having inputs (54, 55) connected to the primary winding terminal (5) and to the battery voltage (VB), and an output (56) connected to the control terminal (8) of the power element (3). The voltage limiting circuit (51) detects a potential difference between its own inputs (54, 55) and supplies to the control terminal (8) an activation signal for the power element (3), in presence of the deactivation signal and when the potential difference exceeds the supply voltage (VB) by a preset value. Thereby, the voltage limiting circuit (51) limits the voltage on the primary winding terminal (5) to a preset value (VL) which depends upon the value of the battery voltage (VB).