Patent ID: 6137392
Filing Date: 2000-10-24
Classification: H01F,H02M

Abstract:
A transformer for switched mode power supplies and similar applications with very low end for end interwinding capacitance, and very high end for end dielectric isolation, having an electrical input for receiving electrical power from a source of electrical power and having at least a first electrical output for delivering electrical power to an external load, comprisingan input transformer stage characterized for very low input leakage inductance and good coupling without regard for interwinding capacitance and dielectric isolation,and at least a first output transformer stage characterized for very low interwinding capacitance and high dielectric isolation,the input transformer stage comprising an input transformer stage primary winding and an input transformer stage secondary winding wound on an input transformer stage magnetic core,the at least a first output transformer stage comprising an output transformer stage primary winding and an output transformer stage secondary winding wound on an output transformer stage magnetic core,the input transformer stage primary winding comprising at least one of a single winding, a center-tapped winding and a split winding and further comprising at least first and second input transformer stage primary winding terminations which are the electrical input for the transformer,the output transformer stage secondary winding comprising at least one of a single winding, a center-tapped winding and a split winding and further comprising at least first and second output transformer stage secondary winding terminations which are the at least a first electrical output for the transformer,the input transformer stage secondary winding comprising a single winding having first and second input transformer stage secondary winding terminations,the output transformer stage primary winding comprising a single winding having first and second output transformer stage primary winding terminations,the first input transformer stage secondary winding termination being connected to the first output transformer stage primary winding termination,the second input transformer stage secondary winding termination being connected to the second output transformer stage primary winding termination,in the input transformer stage, the input transformer stage secondary winding is very closely wound with the input transformer stage primary winding with minimal insulation and space between them for good coupling and low leakage inductance,and in the at least a first output transformer stage, the output transformer stage primary winding has a minimal surface area and a large spacing to the output transformer stage secondary winding for very low interwinding capacitance and high dielectric isolation,whereby the transformer as a whole will have very low end to end interwinding capacitance and very high end to end dielectric isolation.