SMT Current-Sense Transformers for Automotive ElectronicsOctober 30, 2014 by Jeff Shepard
TDK Corporation has added two new EPCOS SMT current sense transformers for automotive electronics. The first type (B78417A2185A003) is based on an EP7 ferrite core and has dimensions of only 10.6 mm x 12.2 mm x 11 mm. It is designed to measure pulse currents of up to 20A. The dc resistance is 1.3 mΩ on the primary side and 3.7 Ω on the secondary side. The second SMT current sense transformer (B78419A2251A003) contains an EP10 ferrite core and measures 12.8 mm x 13.6 mm x 14.4 mm. The measurement range of the larger type extends to 30 A. Its dc resistance is 0.5 mΩ on the primary side and 2.7 Ω on the secondary side.
Both transformers have a turn ratio of 1:100 and are suitable for the wide temperature range from -40 to +150 degrees C. The test voltage between the primary and secondary sides is 2800 V DC. The creepage and clearance distances meet the requirements for basic insulation according to IEC 60664. The new transformers are qualified to AEC-Q200.
The SMT current sense transformers are designed for use in emerging 48-V automotive power systems as well as for all xEV applications, where the components can be used to measure the currents of the electric drives.