ELECTRIC POWER SUPPLY CIRCUIT, ELECTRODELESS DISCHARGE LAMP LIGHTING DEVICE, LIGHTING SYSTEM

摘要

PURPOSE: To prevent breakage of an element even when an electrodeless discharge lamp becomes no-lighting after start. CONSTITUTION: A main matching circuit 5 connected to an excitating coil L which supplies energy to an electrodeless discharge lamp 6, an auxiliary matching circuit 10 which makes an absolute value of an input impedance containing the main matching circuit 5 larger than that before connection when connected to the main matching circuit 5, and a switching means SW2 which separates the auxiliary matching circuit 10 from the main matching circuit 5 when the electrodeless discharge lamp 6 starts, then connects the auxiliary matching circuit to the main matching circuit 5 are arranged. The switching means SW2 is operated so that the auxiliary matching circuit 10 is separated from the main matching circuit 5 in the start of the electrodeless discharge lamp 6, then connected in non-lighting, and flowing of large current to an element on power supply side after start of power supply is prevented.