LIGHTING DEVICE FOR HIGH VOLTAGE DISCHARGE LAMP, HIGH PRESSURE DISCHARGE LAMP LIGHTING DEVICES, LIGHTING SYSTEM, AND VEHICLE

摘要

PROBLEM TO BE SOLVED: To provide a lighting device for a high pressure discharge lamp capable to suppress damages on a high pressure discharge lamp by supplying rated lamp current for a prescribed period after high pressure discharge lamp is started and then supplying lamp current corresponding to the lamp voltage and to provide a lighting system an a vehicle. SOLUTION: A high pressure discharge lamp 18 is connected with an output side of an electric power conversion circuit 13 comprising a field-effect transistor FET as a semiconductor switch for chopping direct current while a high voltage generating circuit 17 being connected between them. The circuit 17 applies high voltage pulses to a lamp 18 to start the lamp 18. a lamp voltage detection circuit 15 and a lamp current detection circuit 16 are connected with the output side of the circuit 13. The circuit 15 is connected with the input side of a microcomputer circuit 19 through a buffer 21, the output side of the circuit 19 is connected with a reversible input terminal of an operational amplifier OP2, the non-reversible input terminal of the operational amplifier OP2 is connected with the circuit 16. The circuit 24 of the circuit 19 computes the electric current value by dividing the electric power value such as the rated power value of the lamp 18 stored in a RAM by the lamp voltage and transmits the result to the OP2.