#Toroidal transformer design software how to#

The inter-winding capacitance consists of the individual local inter-winding capacitances as indicated in the diagram. The voltage over the primary winding is V p and the resulting output voltage over the secondary winding is V s = a.V p, where a is the turns ratio.

The primary winding is blue and the secondary winding is orange. A simple single layer E-core transformer is used to demonstrate the concept. In the diagram below the inter-winding capacitance is shown. The transformer capacitance is divided into inter-turn and inter-winding capacitance. Larger voltage differences will result in larger displacements currents and larger equivalent capacitances. The key is to look at the voltage differences within the transformer. The parasitic capacitance of a transformer cannot be calculated using simplified electro-static techniques. Turns ratio, transformer capacitance and the DQ factor Different pulse transformer topologies will have more or less equal DQ factors, but the relative size of the leakage inductance and equivalent transformer capacitance can vary greatly. For high-voltage pulse transformers the DQ factor is also larger due to larger insulation distances required between transformer turns and windings. In most cases the DQ factor becomes larger for larger turns ratios. A well-designed pulse transformer will have a relatively small DQ factor - a good DQ performance. Smaller DQ factors imply faster transformers with larger bandwidths.

The DQ factor translates into the bandwidth of a pulse transformer. Where L leakage is the equivalent leakage inductance and C par is the total equivalent transformer capacitance as seen over the input (primary or secondary) of the transformer. In this respect, the design quality factor, DQ, can be defined: voltage, turns ratio, etc.) the product of the leakage inductance and total equivalent transformer capacitance remains more or less constant. For a given set of design parameters (e.g. A smaller capacitance in most cases implies larger winding separation and a larger leakage inductance. A smaller leakage inductance implies a more closely packed winding configuration with a higher parasitic capacitance. In most cases both quantities cannot be minimised at the same time. A practical, real-world transformer has a finite leakage inductance and capacitance. Unfortunately, this does not happen in the real world. As a result the ideal transformer has an infinite bandwidth. The ideal transformer has no leakage inductance or parasitic capacitance.

In the diagram below the relationship between the leakage inductance and equivalent transformer capacitance is shown for ideal and real transformers. In most cases the magnetisation inductance can be ignored in pulse transformers and the leakage inductance, the inter-turn capacitance and the inter-winding capacitance are dominating the transformer characteristics. When it comes to pulse transformers a third aspect is introduced: the transformer capacitance. We were taught that the magnetisation and leakage inductance are the most notable differences between an ideal and real transformer. Let us now look at the ideal transformer and what happens in a practical, real-world transformer.

#Toroidal transformer design software how to#

This post will focus on certain key aspects to show how to think and approach pulse transformer design. This plays a very important role in the selection of the best pulse transformer topology. It is important to understand the pulse application you are designing for. Before reading this post it is important to maybe first read that post.

Some time ago I wrote a post on different pulse power supply types.