| 摘要 |
PROBLEM TO BE SOLVED: To obtain a separately excited switching power supply 21 having a circuit 22 for controlling a switching operation depending on a secondary output voltage Vo in which an operation is stopped in safety without generating noise in the output voltage Vo and without generating an undesired high current even in the power supply 21 arranged to stop the operation stably by interrupting power to the control circuit 22 when the output voltage from a rectifying circuit is lowered by a voltage detecting circuit 24 and a switch circuit 25. SOLUTION: Since a detection voltage is lowered by an amount corresponding to a voltage division ratio as compared with a case where the detection voltage is imparted directly to the voltage detecting circuit 24 from the joint of starting resistors R1 and R2, power to the control circuit 22 is interrupted at a relatively early stage even when a high voltage is used and a switching operation is stopped. Consequently, an undesired high current is generated in a primary circuit and an operation can be stopped in safety. COPYRIGHT: (C)2004,JPO
|
