| 摘要 |
PURPOSE:To reduce pulsating voltage and to improve stability in output voltage by changing stepwise the amplification of an error amplifying circuit connected to the output terminal of a DC-DC converting circuit. CONSTITUTION:An error amplifier circuit EA is connected to an output terminal of a switching transistor TR2 connected to an input terminal 1. The error amplifying circuit EA is composed of a comparator circuit 61, voltage dividing resistors 64, 65 connected to an input of one side of said 61, voltage dividing resistors 45, 46 connected to the outputts of said 64 and 65. A connecting point 47 of the voltage dividing resistances 45, 46 is connected to an input of one side of the comparator 41 and a master oscillator 44 is connected to an input of the other side of the comparator circuit 41. An output of the comparator circuit 41 is connected to the base of a driving TR31 of said TR2. With such constitution, the amplification of the error amplifying circuit EA changes step wise and pulsation in the output voltage is reduced and stability in the constant voltage is improved. |
