| 摘要 |
PROBLEM TO BE SOLVED: To make one gate pulse generator in order continuously operate even if the other gate pulse generator gets out of order, by a method in which two sets of pulse generating means, current application period signal abnormality detecting means and gate pulse stopping means are respectively provided. SOLUTION: The output of an AND circuit 3A is inputted to a one-shot circuit 4A through an AND circuit 43A. The output of a flip-flop circuit 42A of a current application period signal abnormality detection circuit 40A is connected to the other input terminal of the AND circuit 43A through a reverse circuit 44A. The AND circuit 43A has a function which stops a gate pulse by which the supply of a light ignition signal to a thyristor bulb is stopped in accordance with the output of the current application period signal abnormality detection circuit 40A. With this constitution, the operation of a gate pulse generator out of order is stopped and thyristor bulb can continue operation by the other gate pulse generator in order. |
