Open AccessApplication of ferrite layers in low‐profile OLED drivers
Author(s) -
Kundrata Jurica,
Baric Adrijan
Publication year - 2018
Publication title -
iet power electronics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.637
H-Index - 77
eISSN - 1755-4543
pISSN - 1755-4535
DOI - 10.1049/iet-pel.2016.1026
Subject(s) - inductor , electromagnetic coil , inductance , ferrite (magnet) , materials science , ripple , planar , optoelectronics , electrical engineering , electronic engineering , engineering , computer science , composite material , computer graphics (images) , voltage
Driver of a low‐profile organic light‐emitting diode (OLED) luminary due to space constraints uses a planar inductor with ferrite layers to realise desired inductive properties. This study presents the analysis of usage of ferrite layers with single‐coil and double‐coil windings in the OLED driver. The model based on magnetic circuits is used to analyse the inductance and the quality factor. The influence of the winding dimensions and the ferrite layers is analysed. The analysis is verified by electromagnetic simulations and measurements. The results of vector network analyser measurements show that the double‐coil design has the maximum inductance ∼80% and maximum quality factor ∼10% larger than the single‐coil design. The measurements of the planar inductors in the OLED driver show that the best‐case single‐coil and double‐coil inductors have a similar efficiency, but the double‐coil inductor has a 35% smaller current ripple which leads to better EMC performance of the driver. It is concluded that it is sufficient that the ferrite layer covers the inductor, i.e. it does not have to be much larger than the inductor to achieve good performance.