| 摘要 |
PURPOSE:To provide a small filter circuit and a simple control circuit in a power supply unit that includes a switching element and a voltage multiplier circuit made of a capacitor and a diode as a switching means, by limiting a change in the number of pulses in a narrow range so that noises are limited in a given range when the pulses are fed to a switching element. CONSTITUTION:A power supply unit includes a first-group output means for generating a maximum voltage of E, 3E, 5E, 7E or 9E, each obtained from a minimum power-supply voltage multiplied by odd numbers, and a second group output means for generating a voltage 2E, 4E, 6E, and 8E, each obtained from an minimum power-supply voltage multiplied by even numbers. Then, the first-group and second-group output means are alloted in different voltage ranges. In addition, the power supply unit includes switching means S21 to S28 for switching the connection between each output means and a load, and control means 1 and 11 for controlling switching elements in a way that the output voltage from the output means changes in the allotted range. |
