| 摘要 |
PROBLEM TO BE SOLVED: To provide a lamp power supply circuit capable of easily re-lighting a lamp even after it is continuously turned on. SOLUTION: A temperature sensing posistor 33 senses the temperature of a high voltage discharge lamp 4. Spark gaps 32a, 32b generate ignition pulses. Of bidirectional thyristors 31a, 31b connected in series with each other, the bidirectional thyristor 31b has a switch S1 connected in parallel therewith. When the temperature of the high voltage discharge lamp 4 is low, switches S1, S2 are turned on and a switch S3 is turned off, whereas when the temperature of the high voltage discharge lamp 4 is high, the switches S1, S2 are turned off and the switch S3 is turned on, so as to selectively switch the spark gaps 32a, 32b from one to the other. Thus, the voltage of the ignition pulse is changed over. |
