A wide-band current sensor for power electronics

A resistive current sensor with a wide frequency band (from DC to several MHz) has been developed for the use in power electronics. The sensor is constructed as a volume resistor (1-10 m/spl Omega/) with minimum parasitic parameters in a wide frequency range and it can be used as a current sensor in circuits with an effective current range of tens of amperes. The resistor is realised from a wafer of sintered graphite on which are soldered copper strips using soft soldering with a lead-free solder. The temperature coefficient of resistance is negative and not higher than 10/sup -4/ K/sup -1/. An advantage of this type of current sensor is its resistive character allowing to measure also DC current. At high frequencies, the measurement accuracy is units % at 1 MHz and 10% at 10 MHz due to parasitic parameters. The sensor is suitable for the in impulse circuits with respect to its frequency characteristics (a transmission loss at higher frequencies), because of distortion of pulses resulting in moderation of impulse front edge and not in overshoots.