Title:
DISCHARGE LAMP LIGHTING DEVICE
Document Type and Number:
Japanese Patent JPH01189893
Kind Code:
A
Abstract:
PURPOSE:To prevent an over current to a switching element by connecting a voltage detection circuit to both ends of capacitance for pre-heating of a discharge lamp together with controlling the output control part by output of the AND working part at the time of detecting an H level. CONSTITUTION:When both ends of a discharge lamp 2 are not connected, both of the voltage detection circuits 4 and 5 send output of an 1 level to the AND working part 6 so as to make output of the working part 6 L and the output control part 7 stops oscillation of a high frequency power supply device 1. When both ends of the discharge lamp 2 are connected, output both of the circuits 4 and 5 becomes an H level and output of the AND working part 6 also becomes the H level so as to start oscillation of the power supply device 1 with output of the control part 7. As oscillation surely starts from a state of high frequency, an overcurrent is prevented from flowing to a switching element of the device 1 to break the element, while being able to prevent from lowering a life of the discharge lamp by surely providing a pre-heating period.
Inventors:
YAMAMOTO AKIRA
NAGASOE KAZUFUMI
NAGASOE KAZUFUMI
Application Number:
JP1506988A
Publication Date:
July 31, 1989
Filing Date:
January 26, 1988
Export Citation:
Assignee:
MATSUSHITA ELECTRIC WORKS LTD
International Classes:
H05B41/24; (IPC1-7): H05B41/24
Attorney, Agent or Firm:
Ishida Choshichi