For power electronics applications, TDK-Epcos has introduced a new surface mount current detection transformer. Various types of B78417A series devices are based on EP7 ferrite cores, are compact in size only 10.6mm x 12.2mm x 11mm, and are designed to measure pulse currents up to 20A.
The maximum DC resistance on the primary winding is 1.9mohm. The SMT current sensing transformer in the B78419A series is designed with an EP10 ferrite core. These components measure 12.8mm x 13.6mm x 14.4mm and their measurement range can be extended to 30A. The DC resistance is only 0.5mohm.
Each series has a different turns ratio: there are four versions of EP7-based transformers with turns ratios between 1:50 and 1: 125, while EP10 transformers are available in five versions with turns ratios of 1:50 And 1:25. 1: 180. Allowable operating temperature range is -40C to + 150C. This transformer is suitable for measuring current in the frequency range from 50kHz to 250kHz.
Possible applications include switched-mode power supplies and all types of converters. The test voltage between the primary and secondary sides is 2400VAC, and the creepage distance meets the requirements of IEC 60664 for basic insulation. Because these components meet the requirements of AEC-Q200, they can also be used in xEV applications, such as for measuring currents, the company said, for applications in DC-DC inverters.
