| 摘要 |
PROBLEM TO BE SOLVED: To prevent occurrence of overshooting of output voltage at an early stage of starting in a soft start power supply unit comprising a DC/DC converter. SOLUTION: The soft start power supply unit is provided with a control circuit (control IC4) comparing detection voltage detecting output voltage of the DC/DC converter 1 with comparison reference voltage and controlling the DC/DC converter 1, a control IC soft start circuit 5 inputting voltage which gradually drops at the time of starting to a dead time terminal T1 of the control circuit, an external soft start circuit 6 inputting voltage which gradually rises to a prescribed value at the time of starting to a comparison reference voltage input terminal T4 of the control circuit and a diode D1 connected so that input voltage of the dead time terminal T1 is inputted to a detection voltage input terminal T3 to which detection voltage detecting output voltage of the DC/DC converter 1 of the control circuit is inputted. COPYRIGHT: (C)2008,JPO&INPIT
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