Melexis brings reinforced isolation for its integrated current sensors
Melexis has announced a new safety qualification for the MLX91220 (5V) and MLX91221 (3V) current sensors. They can now be used in systems with higher voltage isolation requirements for both SOIC8 (715V BI, 307V RI) and SOIC16 (1415V BI, 707V RI) packages. This upgrade expands the application range and reduces the Bill of Material (BoM) component count. Applications requiring reinforced isolation include OBC and HVAC/compressor.
To guarantee the safety and isolation of high voltage class 3 energy sources, such as 800V EV battery packs and chargers, two isolation barriers must be implemented to reduce it to a low risk. Until now, the MLX91220 and MLX91221 had only been qualified as a basic (i.e. single) isolation device, mandating the need for an engineer to incorporate extra elements like an isolation amplifier into their design.
With the new UL/IEC 62368-1 certification (material group I), engineers can now use Melexis Hall-effect sensors, knowing its reinforced isolation is enough to safeguard the end user from high voltage risk without needing additional isolation barriers. The new voltage ratings are (for a pollution degree 2):
● for the SOIC16 package: 1415 V for basic isolation (BI) and 707 V for reinforced isolation (RI)
● for the SOIC8 package, 715 V for basic isolation (BI) and 307 V for reinforced isolation (RI)
Engineers currently using the MLX91220 or MLX91221 with an extra isolation barrier, can now eliminate the unnecessary isolation components. Additionally, for designs that currently have only basic isolation, it provides the possibility of re-qualifying as a reinforced isolated system without any change in the BoM.
The introduction of this ‘upgrade’, solely in the form of further technical qualification, improves the value of the Hall-effect sensors, streamlining designs and reducing the associated engineering efforts and costs. This solution not only maintains its accurate, flexible, and plug & play nature but also provides reinforced safety measures to diverse applications such as automotive on-board chargers (OBC), DC/DC converters, high voltage chargers, renewable energy inverters, white goods, and robotics.
The current sensors come in cost-effective and miniaturised SOIC8 narrow bodies with 4 mm creepage and larger SOIC16 wide-body packages with an 8 mm creepage. Both devices have a bandwidth of 300 kHz, a short response time of 2 us, and are available with a current range between 0-50 A RMS.
The MLX91220 and MLX91221 are available now.
