| 摘要 |
PROBLEM TO BE SOLVED: To provide a control circuit for a switching power source which can multiplex feed back with a simple circuit configuration and which can accelerate by improving phase characteristics and reducing a gain change. SOLUTION: The control circuit for the switching power source includes a switch element SW for switching a DC voltage, a controller 70 for driving the switch element SW and a rectangular wave signal generator such as an output choke coil L1 for generating a rectangular wave signal substantially proportional to an input voltage and an output voltage by tuning with a switching signal. The control circuit further includes an error amplifier EA which inputs the rectangular signal to an input terminal from the rectangular wave generator through an impedance, and which inputs an output detection signal of the output voltage to the input terminal. The control circuit also includes a light emitting element PCA of a photocoupler PC disposed in a negative feedback circuit between the input terminal and the output terminal of the error amplifier EA, a photodetecting element PCB opposed to the light emitting element PCA, and an integrating circuit 80 for integrating the signal generated from the photodetecting element PCB, and inputs the output of the integrating circuit 80 to the controller 70. COPYRIGHT: (C)2005,JPO&NCIPI
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