| 摘要 |
PURPOSE:To detect the rise-up of an ignition timing sensor surely in spite of the level of the output thereof by a method wherein the connecting condition of a load resistor for determining an amplifying rate is switched in accordance with the output of the ignition timing sensor. CONSTITUTION:Combustion light, detected by the ignition timing sensor, is inputted into a light detector 18 and is inputted into an operating amplifier 30 after converting it into a current signal. Here, it is converted into a voltage signal with the amplifying rate changing in accordance with the values of the load resistors 32, 34. When the output of the light detector 18 is small upon starting at a high land or the like and the output voltage of the operating amplifier 30 is also low, an analog switch 36 becomes OFF by the output of a comparator 34 and the amplifying rate of the operating amplifier 30 becomes a large value determined by the value of resistance of the load resistor 32. According to this method, the rise-up of the ignition timing sensor may be detected surely in spite of the level of the output thereof and, therefore, feedback control may be effected correctly. |
