CURRENT SENSING CIRCUIT FOR USE IN A CURRENT MEASUREMENT PROBE

摘要

A current sensing circuit has a transformer where a current to be measured induces a magnetic flux into a magnetic core. The magnetic core has a magneto-electric converter for sensing DC to low frequency current signals and a secondary winding for sensing higher frequency current signals. The magneto-electric converter generates an output that is coupled via an amplifier to a non-inverting input of a transimpedance amplifier. The inverting input of the transimpedance amplifier is coupled to the secondary winding of the transformer. A current signal path having a transimpedance resistor couples the inverting input to the output of the transimpedance amplifier. The transimpedance amplifier functions as a power amplifier for coupling a nulling current to the transformer for DC to low frequency current signals and functions as a transimpedance gain amplifier for higher frequency signals.