Current sensor boosts accuracy and speed

The CSNA111 closed-loop linear current sensor has improved accuracy and faster response times than open-loop current sensors.

The CSNA111 closed-loop linear current sensor has improved accuracy and faster response times than open-loop current sensors.

A low-cost, high-value sensing solution for use in through-hole printed circuit board assembly applications, the CSNA series closed-loop sensors have been used for overcurrent protection in variable speed drives, as part of feedback control systems in frequency convertors, and for battery management in uninterruptible power supplies (UPSs).

The CSNA111 current sensor's primary features include: AC, DC or impulse current sensing up to 70A with no limitation on the measured current waveform; rapid response time of less than 1us allowing the output signal to closely track the input signal; through-hole sensing which allows the signal to be sensed using a noninvasive connection; galvanic/electrical isolation between primary and secondary; and high overload capability which limits the possibility for sensor damage.

The CSN Series of closed-loop current sensors is based on Hall effect principles and the null balance or zero magnetic flux method (feedback system).

The magnetic flux in the sensor core is constantly controlled at zero.

The amount of current required to balance zero flux is the measure of the primary current flowing through the conductor, multiplied by the ratio of the primary to secondary windings.

This closed loop current is the output from the device and presents an image of the primary current reduced by the number of secondary turns at any time.

This current can be expressed as a voltage by passing it through a resistor.

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