| 摘要 |
PURPOSE:To decrease the number of parts of a rectifying element and also to reduce the power consumption by supplying the output of a constant current controller to an input terminal for detected power supply voltage of a constant voltage controller via a resistance. CONSTITUTION:When the potential different of a current detecting resistance 8 is smaller than that of a reference voltage source 4, resistance 7 is substantially grounded to the negative side of a power supply 11. As a result, the potential at the joint between a voltage detecting resistance 6 and the resistance 7 is proportional to the voltage of the supply 11 which supplies a direct current to a load 12. When the potential of said joint is higher than that of a reference voltage source 3, the output of the power supply 11 is reduced by an error amplifier 1 for acquisition of the constant voltage control characteristics. When the potential difference of the resistance 8 is larger than that of the source 4, the amplifier 2 supplied the due voltage to the resistance 6 via the resistance 7. Thus the potential at the joint between both resistance 6 and 7 is higher than that of the source 3. Then the output of the power supply 11 is reduced by the amplifier 1 for acquisition of the constant current control characteristics.
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