Download - Planar inductor - FER
Inductor design for an ultra low profile DC-DC converter in OLED
lighting applications
Jurica Kundrata, Adrijan Barić
Integrated Circuits and Electromagnetic Compatibility Laboratory
Faculty of Electrical Engineering and Computing
University of Zagreb
January 2013
IC & EMC Lab
Outline
• The FP7 project IMOLA
• Planar inductor: – Design approaches:
• Electrical
• Electromagnetic
• Thermal
– Analysis approaches:
• Mathematical models
• Numerical models (simulations)
• Measurements
• Current work
• Conclusion
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The FP7 project IMOLA – General info
• “Intelligent light management for OLED on foil applications”
• Project objective: – Large-area OLED-based lighting modules with built-in intelligent light
management
• Applications: automotive (dome and tail lightning), wall light
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• Funding: – Seventh Framework
Programme (FP7)
• Project duration: – 2011-10-01 to 2014-09-30
The FP7 project IMOLA – Partners
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The FP7 project IMOLA – Motivation
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• Responsibilities: – Embedded inductor design
(DC-DC converter)
– Electromagnetic compatibility (the whole module)
• Objectives: – Embedded inductor design of:
• Low series resistance (≤ 1 Ω)
• High inductivity (5-10 µH)
• High resonant frequency (≥ 50 MHz)
– Conformity of the lighting modules to EMC standards (CISPR 15)
Planar inductor – Design approaches
Electrical properties
Electromagnetic properties
Thermal properties
Heat spreading layer application
Inductor parameter space analysis
(w, s, R)
Two-layer inductor structures
Ferrite (FPC) layer application
Multi-coil inductor
structures
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Planar inductor – Analysis approaches
Electrical properties
Electromagnetic properties
Thermal properties
COMSOL Multiphysics RF & Heating Module
VNA measurements
Agilent ADS Momentum
Large Loop Antenna (LLA) setup
COMSOL Multiphysics RF Module
Mathematical models
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Planar inductor – Electrical properties (I)
• Electrical analysis: 1. Agilent ADS and COMSOL Multiphysics simulations (2-port S-params)
2. Electrical modelling
3. Verification (VNA measurements)
• Inductor parameter space analysis: 1. Rectangular grid in w-s-R space
2. Identifying parameter-response relationships
3. Mathematical modelling
4. Analysis in the context of the DC-DC converter requirements
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Planar inductor – Electrical properties (II)
Qmax
high Q
C3,min
C3,min low C3 low C3
fr,min limit
The w-s-R space center-point
gradients
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Planar inductor – Electrical properties (III)
Single layer structure Double layer structure
Alternative double layer structure
Ls = 0,233 µH
fr = 181 MHz
Ls = 0,594 µH
fr = 48 MHz
Ls = 0,543 µH
fr = 77 MHz
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Planar inductor – Electrical properties (IV)
• FPC layer application: – “Ferrite Polymer Compound” FPC
– A composite of ferrite particles (D ~ 10 µm) and polymeric filler
– Ferrite NiZn, MnZn, CoZrO, CoNiFe, …
FPC application effects FPC layer thickness effect
Brandon et al., 2003
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Planar inductor – Electromagnetic properties (I)
• Electromagnetic analysis: – COMSOL Multiphysics simulations
– Explicit EM field equations (MATLAB)
– Verification Large Loop Antenna System
(CISPR 16 Annex C, [300 kHz, 30 MHz])
• Multi-coil inductor structures:
+
CISPR 15 limit
noise margin
1L
4L
2L
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Planar inductor – Electromagnetic properties (II)
• Modelling EM field via explicit equations
1L 2L 4L
Magne
tic
fie
ld lin
es
Fa
r-fie
ld
rad
iatio
n
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Planar inductor – Electromagnetic properties(III)
• FPC layer application:
GND
FPC
CISPR 15 limit
noise margin
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Planar inductor – Thermal properties (I)
• Motivation: – Inductor is embedded in an OLED cell backplane
– The OLED cell is sensitive to thermal influences
– Increasing the operating temperature by 10 °C shortens the life span by 1,5 times
– Maximum temperature difference < 2 °C
• Thermal analysis: – Coupled elektromagneic i thermal simulations in COMSOL Multiphysics
– The heating effects of the inductor structure and the DC-DC converter IC
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Planar inductor – Thermal properties (II)
Aluminum heat spreading
layer application
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• DoE-based FPC layer analysis: – ferrite filler percentage, FPC layer thickness, track width and fill ratio
• Discrete DC-DC converter (1+ MHz) design
• EM radiation analysis of an OLED matrix
• OLED modules DALI Interface
• COMSOL Multiphysics Structural Mechanics
module
Current work
UPWM
IOLED
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Conclusion
• General information on the FP7 project IMOLA
• Description of the OLED lighting module
• Planar inductor design approaches: – Inductor design in w-s-R parameter space
– Different inductor structures (double-layer and multi-coil structures)
– Application of different layers (ferrite and heat-spreading layers)
• Planar inductor analysis approaches: – Mathematical models (EM-field and electrical parameters)
– Numerical models (simulations in ADS Momentum and COMSOL)
– Measurements (VNA and Large Loop Antenna)
• Current work
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