Abstract: A direct current boost converter which has a simple structure using only one coil, and which can apply a driving voltage to a capacitive load which reciprocates in polarity is discussed. A first direct current branch circuit composed of first and second transistors is connected in parallel to a second direct current branch circuit composed of the third and fourth transistors. A coil is connected between the intermediate nodes of the transistors of these direct current branch circuits, and these nodes are further connected to both terminals of an EL panel through first and second diodes. The nodes between the first and second diodes and the EL panel are grounded through fifth and sixth transistors, respectively. A clock signal is applied to the first and third transistors, and a gate signal with an opposing phase is applied to the second and fourth transistors.