Sensor selection criteria

When selecting a current sensor, it is necessary to evaluate some standards (or key specifications). This includes:

Requirements for nominal current and overcurrent, current source (AC or DC), current direction (unidirectional or bidirectional);

Accuracy over the entire temperature range: The data sheet should display the total error and the percentage of readings compared to the full scale;

Support the bandwidth required for power level switching frequency;

The output step response measured by di/dt provides an idea of how fast the measurement system needs to be;

Temperature range;

Isolation type;

The scale and cost of the solution;

Electrical and mechanical interfaces;

Other aspects include the required power supply, output type, functionality (such as overcurrent detection), di/dt and dv/dt withstand capacity, UL/IEC certification, simple/easy-to-use design.

Most isolated current sensors do not support the typical high switching speed of wide bandgap semiconductors such as SiC and GaN, and sensors that support them are costly. The current trend is to overcome limited bandwidth and low response time by creating magnetic sensors with high bandwidth and low phase delay. In this way, significant advantages can be obtained, such as bandwidth coverage up to 10 times the switching frequency, output step response time less than 500ns, higher accuracy over the entire temperature range, larger dynamic range, reduced losses at higher frequencies, and smaller size.