COMMON-MODE NOISE REDUCTION METHOD FOR INPUT-OUTPUT INSULATION TYPE EQUIPMENT

摘要

PROBLEM TO BE SOLVED: To effectively reduce common-mode noise which is mixed from the ground-side input terminal of input-output insulation type equipment for imbalanced output. SOLUTION: The input-output insulation type equipment includes a signal input part 10 including an imbalance input type operational amplifier OP connected through protection impedance Z1 to a signal-line side input terminal H and a ground-side input terminal L and a signal output part 20 connected to a signal input part 10 through an insulation type coupler 30. The ground side input terminal L of the signal input part 10 and the ground G2 of the signal output part 20 are directly and capacitively coupled together not through the protection impedance Z1.