| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a switching power source circuit in which an output voltage can reach a target value, even if the switching period of operation/shutdown of the voltage fluctuation operation, according to the external signal is short. <P>SOLUTION: An on/off circuit 21 switches the operation/shutdown of the switching control operation of a drive circuit 13 according to the external signal. A soft start circuit 24 has a discharge unit which has a capacitor C1, a switch SW2 and a constant current source I2, controls the output potential of an error amplifier 18 according to the both ends of the capacitor C1 so that the capacity C1 is charged and the output voltage rises gently, when the switching control operation is started and output voltage starts rising, and discharges the capacitor C1 by the discharge unit during the stoppage of the switching control operation. The time duration taken to complete the discharge is longer than the switching period of the operation/shutdown of the switching control operation by the on/off circuit 21. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
