Isolated current transducers suit SMD assembly
Open loop, Hall-effect, ASIC-based current transducers from LEM are mounted directly onto a PCB as an SO8 SMD device. This reduces manufacturing costs and saves space, says the company.
The GHS series of miniature, IC transducers for AC and DC isolated current measurement up to 100kHz offer full isolation. They integrate the primary conductor for nominal current measurements of 10, 12, 16 or 20A with a measurement span of 2.5 times the nominal current. They are also able to support high overload currents up to 200A peak for short durations (1ms).
The transducers integrate low resistance primary conductors (minimising power losses) within an ASIC to allow direct current measurement and consistent insulation performance, while still providing high creepage and clearance distances, says the company.
All the models provide a ratiometric analogue voltage output with different sensitivity levels from 40 to 80mV/A according to the model, with a typical response time of 5micro sec.
They have been designed with primary integrated conductors for gradient measurement to provide immunity against the external fields found in power electronic applications.
The designs combine field-proven techniques such as spinning, programmable internal temperature compensation (EEPROM) ensuring performance accuracy over the full range of temperature with a maximum 1.3% offset drift and 1.5% gain drift.
The transducers operates from a single 5V supply and over -40 to +125 degree C, for use in any harsh industrial applications.
Target applications are white goods or air conditioning, and also enable enhanced motor control, reducing energy consumption where other methods, such as a shunt, have traditionally been used, says the company. They can also be used in uninterruptible and switch-mode power supplies, home appliances, static converters for DC motor drives and robotics.