Isolator circuit

An isolator circuit comprising:

• a first differential pair circuit having first and second active elements;
• a second differential pair circuit having third and fourth active elements;
• resistors;
• and
• a current comparison circuit;
• wherein a control terminal of said first active element is connected to one input terminal for a balanced input signal, an output terminal of said first active element is connected to one input terminal of said current comparison circuit, and also to one of said resistors;
• wherein a control terminal of said second active element is connected to another input terminal for the balanced input signal, an output terminal of said second active element is connected to another input terminal of said current comparison circuit, and to another one of said resistors;
• wherein a control terminal of said third active element is AC-grounded, an output terminal of said third active element is connected to said output terminal of said first active element;
• and
• wherein a control terminal of said fourth active element is connected to an output terminal of said current comparison circuit, and an output terminal of said fourth active element is connected to said output terminal of said second active element.