LLC Transformer

Pulse is excited to announce the launch of its first LLC transformer specifically designed for SiC/GaN device switching. The PMT6709NL delivers 2W of power which can be configured with LLC controllers such as the TI UCC25800-Q1 or the MPS MPQ18913 to provide positive and negative outputs for robust switch on/off. The extended creepage UI5 platform provides 3.75kVrms Hi-Pot isolation voltage in a compact (17.2x11x8.5mm max) SMD platform. This IATF design is compatible with full winding automation to fulfil the requirements of high reliability in automotive applications. 


Designed for applications such as inverter motor drives that are driven by high voltage batteries, this platform satisfies the 9.1 mm min creepage requirement of IEC 61558-1 for basic insulation and a working voltage up to 850Vrms, or up to 450Vrms working voltage for applications that require reinforced insulation. A split bobbin is use to keep the interwinding capacitance to less the 2.5pF.


Flyback and Push-Pull topologies have traditionally been used for MOSFET drive circuits. Tight coupling is necessary to minimize transformer leakage inductance, which enhances the efficiency of the drive circuit. However a tightly coupled transformer design results in relatively high interwinding capacitance, limiting higher switching frequency and the full utilization of the benefits of using SiC/GaN Mosfets.

This is overcome with the two section PMT6907 winding construction and the LLC topology, where its higher leakage inductance does not impact on efficiency as it can be used as part of the resonant circuit. It can even potentially eliminate the need for an external resonant inductor. The lower capacitance enables an order of magnitude reduction in the common-mode current injection through the bias transformer and the LLC soft-switching feature further reduces the EMI noise.”

Gerard Healy Product Marketing, Specialized Power PBU, Pulse Electronics


Additionally, PMT6907NL is compliant with the requirements of IEC 60664, for basic insulation and a repetitive peak voltage up to 900Vpk, based on the partial discharge method. Further information is available in our white paper “Partial Discharge Explained” to better understand how this test method is used to define the voltage rating of an insulation barrier.


The new extended creepage UI5 platform is one among the number of high isolation platform developed by Pulse Electronics which are available in our High Isolation Transformer Platform Guide.

To inquire about lead times, competitive pricing, samples and more, just contact us or use our quote form accessed using the button below.