| 摘要 |
PURPOSE:To reduce the power consumption and improve the rise characteristics of lap discharge in a lap discharge type igniter having a resonant forward converter by connecting a high voltage diode in parallel to the output port of the converter. CONSTITUTION:An igniter 3 detects a signal synchronous to the rotation of an engine with a pickup coil 3a, and controls the energized time of a power transistor with a control circuit 3b. A current in the primary coil of an ignition coil 4 causes the secondary coil to generate its self-induced voltage, leading to the insulation breakdown between the electrodes of an ignition plug 5. A discharge current causd by the self-induced voltage, including an impulse current created by a capacity discharge at the time of spark discharge, flows into GND through a high voltage diode 20, and a voltage at the terminal P of a condenser 19 is reversely charged by the foward voltage drop of the high voltage diode 20. In this way, without giving any harmuful effect on the rise of a lap discharge voltage or a terminal voltage at P, the power consumption can be reduced with no overloading to a forward converter. |
