| 摘要 |
PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device in which at least lamp current is detected with a simple resistive element and the value detected with the resistive element can be inputted to a control circuit directly, and to provide a lighting apparatus in which the discharge lamp lighting device is installed. SOLUTION: The discharge lamp lighting device 1 includes a lamp current detection means 5 which detects the lamp current flowing through a high-pressure discharge lamp 4 by converting the lamp current into correlative voltage Vd with the resistive element R7; a DC voltage generating means 7 which outputs constant DC voltage Vc; a superposing means 8 which superposes the DC voltage Vc on the correlative voltage Vd, and outputs sum voltage Vsum after the superposition; an operation means 10 which calculates lamp electric power from lamp voltage and the sum voltage Vsum; and a control means 11 which controls on-off actions of switching devices FET 2 (Field Effect Transistor 2) and FET 3 of an inverter circuit 3, so that the lamp electric power becomes a target value. COPYRIGHT: (C)2007,JPO&INPIT |
