Isolator circuit with improved frequency response

Abstract

An isolator circuit of the type designed to accept an input current and to generate a corresponding output current which is isolated from the input. The isolator circuit is formed with a core developing a flux in response to the input current and having a feedback winding for carrying the isolated output current. A magneto-sensitive element, such as a Hall effect element, responds to flux in the core, and an amplifier receives the output of the magneto-sensitive element and supplies a current to the feedback winding so as to cancel the flux produced in the core due to the input current. Improved frequency response is attained by means of a compensation winding disposed to respond to the difference between the flux produced by the input current and the flux produced by the output current. The compensation winding is connected in the isolator circuit with the voltage developed across the compensation winding being superposed on the output of the magneto-sensitive element and supplied to the input of the amplifier. The voltage developed across the compensation winding leads the voltage across the magneto-sensitive element and compensates for phase lags arising in the current, thereby extending accurate frequency response of the circuit.

Dependencies are inferred from the claim text.