Current Transducer Exploits Open-Loop Hall Effect

LEM S.A.’s HMS model current-transducer uses an ASIC designed for use with open-loop Hall-effect technology to provide performance improvements. These include better offset and gain drifts and linearity, in addition to an extended operating temperature range of -40°C to +85°C. The unit measures 16 mm x 13.5 mm x 12 mm and integrates a primary conductor. It is directly surface-mounted onto a printed circuit board, reducing manufacturing costs.

Four standard models are available to cover nominal ac, dc, pulsed-current, and mixed-isolated current measurement of 5 A, 10 A, 15 A or 20 A, up to 50 kHz, with a measuring span of up to ± 3 x IPN. The same mechanical design is used for all four models. The unit operates from a single +5-V power supply. The internal reference voltage (2.5 V) is provided on a separate pin or can be forced by an external reference (between 2 V and 2.8 V) for reference thermal drift cancellation.