LTspice: Using Transformers

 Transformers and coupled inductors are key components in many switching regulator designs to include flyback, forward and SEPIC converters. They perform critical function in providing an isolation barrier, enabling high step-down or step-up ratios and accommodating multiple or inverting outputs. Although it is possible to make a dedicated subcircuit for a specific transformer, LTspice preferred method is to define a separate inductor for each transformer winding and then couple them all together magnetically via a single Mutual Inductance (K) statement. This video will provide an overview on how to define a transformer using inductors, specify the mutual inductance via a (K) statement and lastly show how to add multiple windings to a simulation.