| 摘要 |
PURPOSE: To provide a rush current preventive circuitry used for a power circuit which is advantageous for miniaturizing and can easily comply with the standard such as ETSI, etc. CONSTITUTION: An oscillation circuit 7 outputs a high frequency pulse signal at the same time when input voltage is applied to it. A drive circuit 6 receives a high frequency pulse signal and outputs control voltage. MOSFET 5 switches input voltage, according to control voltage. When the switched input voltage is applied to a coil 8, a current flows to MOSFET 5 only in the continuity period of MOSFET 5, and it charges a capacitor 10. In the discontinuity period of the MOSFET 5, the charge to the capacitor 10 stops, and the current of the coil 8 decreases while circulating in the coil 8 and a diode 9. The capacitor 10 is charged with every high frequency pulse signal, and the peak value of this charge current becomes small gradually, and it becomes zero with the completion of charge of the capacitor 10. The curve enveloping the peak value of this current value takes the waveform of a rush current. |
