| 摘要 |
PURPOSE:To attain constitution suited to integration without using any power supply filter equipped with a large-size capacitor, by providing a power supply noise detecting circuit to produce a signal proportional to the power supply noise and obtaining the sum or difference between the output current of said power supply noise detecting circuit and the detection current of a balancing signal to offset the power supply noises. CONSTITUTION:For a balancing signal detecting circuit shown in the diagram, the output current of a current detector A2 is converted into the opposite direction by a current detector A3 in order to set a power supply noise Iv', which is mixed during detection in the same direction as the output current of a current detector A1. The noise Iv' is contained in a current Io' added with the output of the detector A1. While in a power supply noise detecting circuit, a signal Iv having the same amplitude as and adverse phase to the power supply noise mixed during detection is generated internally. The current Io' of a balancing signal detecting circuit is added with the output current Iv of the power supply noise detecting circuit through an adder circuit (+). Then the noise component Iv' contained in the current Iv is offset to the noise detection output current Iv. Therefore, the current value Io'-Iv'=I3 containing no noise component is obtained. |
