| 摘要 |
PROBLEM TO BE SOLVED: To prevent a rush current at the time of power-on in a step-up power-supply device.SOLUTION: A step-up power-supply device includes: a coil L0 having one end connected to a power-supply line Lp to which a power-supply voltage VB is supplied; a step-up switch T0 provided in series on a path between the other end of the coil L0 and a reference potential; a diode D0 having an anode connected to a path connecting the other end of the coil and the step-up switch T0; a capacitor C0 provided in series on a path between a cathode of the diode D0 and the reference potential; and step-up control means 36 for charging the capacitor C0 by performing step-up control that repeats on/off of the step-up switch T0. A current limiting resistor R1 is connected in series to the capacitor C0, and a switch T1 is connected in parallel to the resistor R1. A microcomputer 38 turns off the switch T1 at the time of power-on to the power-supply line Lp, then switches the switch T1 to an on-state, and then causes the step-up control means 36 to start the step-up control. |
