I - The Product

The term "inductor" refer to a wide category of inductive components, with a big variety of applications and goals, but they all act like “energy tanks”. For example, by considering the output filtering stage of a high frequency DC/DC converter, the output inductor continuously swaps the electrical energy with the output capacitor. As the inductor function is to contain the variation of current, the current through the inductor is normally mainly direct current with a superimposed high frequency current ripple (at the switching frequency, or its double value, depending on the topology).

 Similarly, by considering the Power Factor Correction (PFC) stage of a high frequency converter, there is a high frequency energy swap involving the inductor and the capacitor; in that case, the current through the inductor is mainly composed by the mains frequency harmonic and a superimposed current ripple at the working frequency of the PFC stage. Similar inductors are also used in non-isolated high frequency conversion topologies (Buck, Boost, Buck-Boost), in which the current waveforms change depending on the mode of conduction, that is if the converter works in continuous or discontinuous mode.

Industrial applications often require dedicated inductors, as every one needs well defined characteristics. For this reason, Sirio chose to dedicate great efforts to customized choke development, automatic production-oriented, instead of an inductors catalogue, based on standard raw materials, typically available at our wharehouse. This kind of approach makes possible a just in time production of a custom component with the same cost of a catalogue product.
Main features of inductors are the following ones.

  • Ln rated inductance value
  • Rn rated winding resistance
  • In rated current (average value in case of output inductors)
  • Imax maximum current (the core has not to saturate at that peak current value)
  • Irms rms current (thermal current value)
  • ΔI peak-to-peak ripple current
  • fn rated working frequency (ripple frequency)
  • Un maximum working voltage (maximum voltage across the winding)
  • Up isolation voltage between winding and core or between winding and case

In this section, we will not show any standard component. Starting from the customer specification, our Research and Development team will suggest the best solution for the application.