| 摘要 |
PURPOSE:To enable a plasma ignition system to be operated always very efficiently irrespective of change in temperature by detecting parameters corresponding to efficiency of a boosting transformer and automatically changing switching frequency so as to maintain always the efficiency at the best value. CONSTITUTION:The output of a voltage frequency converter 6 is given directly to a transistor TrQ2 and through an inverter 7 to a transistor TrQ1. Thus, TrQ1 and TrQ2 are alternatively turned on and off and current from a battery VB flows into the primary winding of a boosting transformer 5 to rectify high voltage of the secondary winding with diodes D2-D5 and generate the output. The current in the primary winding of the boosting transformer 5 is converted into point A voltage by a resistor R1. Peak-hold circuits 17, 18 holds the maximum value of point A voltage with a predetermined time constant to generate the output. Next, the output of a oscillator 8 is given through the inverter 14 to a sample hold circuit 12 and directly to a sample hold circuit 13. Also, each output of the sample hold circuits 12, 13 is compared by a comparator 11 with respect to the magnitude. Thus, switching frequecy is automatically controlled. |
