| 摘要 |
PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device having a DC-DC conversion circuit, capable of reducing power loss and obtaining a stably switching operation by operating in nearly boundary mode in stably lighting in a stationary state, even if the upper fluctuation range of a lamp voltage exceeds a power supply voltage. SOLUTION: The discharge lamp lighting device is provided with: a step-up/down converter 2 having a switching element 22 for switching a current flowing in an inductive element 21, capable of converting input voltage from DC power supply 1 to output voltage from low voltage to high voltage in comparison with the voltage; power conversion circuits 2, 3 for applying the converted electric power to a discharge lamp 5; and a control circuit 6 for performing switching control so that the switching element 22 is turned on again, after providing a predetermined delay time by a delay circuit 650 from the time the current of the inductive element 21 reaches near zero, after the switching element 22 consisting of the step-up/down converter 2 is turned from ON to OFF, under the condition that at least the discharge lamp 5 be lit stably in a stationary state. COPYRIGHT: (C)2010,JPO&INPIT |
