| 摘要 |
PURPOSE:To eliminate the damage of a switching element by limiting a current flowed to the switching element in case of starting. CONSTITUTION:A negative input voltage is applied to a terminal 15. The set value of an input voltage is detected by a Zener diode 13 and a resistor 14. The detected set voltage is inputted to a time constant circuit which has a resistor 11 and a capacitor 12, and the output of the circuit applies an external modulation to an oscillator 7. The output of the oscillator 7 and the output of a pulse width modulator 8 are taken in NAND by a gate circuit 10, and the output of the NAND is inputted to a drive circuit 9. The ON time of a switching element 4 at the starting time after the input voltage is applied is gradually increased, and the DC output is gradually approached to the set voltage. |
