The LED has become the preferred lighting sourcein Automotive applications. The benefits of small form-factor, high efficiencyand low power consumption has seen their deployment in all Automotive applicationsincluding Head Lights, Day time lights, Fog lamps, Indicators, cabin anddashboard lighting.

LEDs require a DC/DC driver circuit whereinductors are used for energy storage. Making them a critical component in thisapplication. Typical circuit designs include Buck, Boost, Buck-Boost, Flyback,Foward and SEPIC (Single Ended Primary Inductance Converter). SEPIC is the mostpopular as it enables output voltage to vary from the input whilst polarity inunchanged. Usually two inductors, in a single package, are used to minimiseboard space and leakage inductance.

The impact of the inductor to the efficientoperating of these circuits is major consideration. Depending on the drivercircuits inductors can be used with LEDs either separately, in parallel or inseries. The current rating of the inductor is a key parameter to ensure correctoperations and prevent saturation. To allow for sufficient margin it issuggested to always consider the Isat of the inductor. Ambient temperature,inductor temperature range and inductor self-heating are all closely associatedwith saturation.

Other aspects of inductor design to considerinclude, is a shielded type needed to minimise the effect of any noise in thecircuit? Also, DCR may affect performance and it is suggested to check with theIC driver supplier has any recommendations on these parameters.

E&E Magnetic Products Ltd has been supplyinductors for Automotive applications for many years and has developed our ARISand ASIS  standard and custom rangesfeaturing high Isat in a wide choice of Inductances values, with temperatureranges from -55’C to +165’C (sizes dependant). Products are AEC-Q200 compliantand manufactured in our IATF16949:2016 qualified production facilities.