STEP-UP/DOWN TYPE POWER CONTROL CIRCUIT AND DISCHARGE LAMP LIGHTING DEVICE

PROBLEM TO BE SOLVED: To provide a step-up/down type power control circuit adaptable to wide power voltage, highly efficient, and miniaturizable and inexpensive with a smaller number of components, and to provide a discharge lamp lighting device. SOLUTION: The step-up/down type power control circuit comprises a first coil L1, a first switching element Q11, and a second switching element Q12 connected in series to one another in a range from the positive electrode toward the negative electrode of a DC power supply, a third switching element Q13 and a second coil L12 connected in series to each other in a range from between the first switching element and the second switching element toward an output end, a capacitor C1 connected between the downstream side of the second coil and the negative electrode, a pulse width modulator circuit U10, and a gate controller GC for controlling the first to third switching elements to be opened/closed depending on pulse waves output by the pulse width modulator circuit. COPYRIGHT: (C)2009,JPO&INPIT