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Payton is an international group of companies handling and promoting magnetic components, with sales offices and plants in Israel, Europe, United States and the Far East. As a global leader of both conventional and planar transformers, with more than 15 years of research and development experience, Payton offers a wide range of custom designed products that meet all the requirements and standards for a variety of specific product applications.
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Planar Magnetics
benefits
Planar Technology
• The Same Physics - used in an innovative way
• Tremendous decrease in size/volume
• Incredible weight reduction
• Very High efficiency - 98% typical
• Excellent parameter repeatability and consistency
• Operating frequency range 50 kHZ – 2 MHZ
• Unique safety solution.
• Decrease inner temperature of Power Supply
Planar Transformer Structure
Ferrite
Conductors
Bobbin (Optional)
Insulators
Ferrite
Bobbin (Optional)
Conductors
Insulators
Planar Planar
Conventional
SMPS Block Diagram
Dimensions
Transformer dimensions
Cooling Power Frequency
Current Voltage
Cores cross section Ae Turns Ratio Current Density Copper Area
Flux Density Bp
Core Losses Insulation Losses Copper Losses
(Skin & Proximity)
Total
Losses
Temperature
Less Copper Loses
• Skin Effect
• Proximity Effect
• Leakage inductance
Function of the Construction
Smaller Skin Effect
High frequency currents in the conductor
generate a variable magnetic field that induces
voltages and, consequently, currents. The
latter are directed in such a way to reinforce the
current flowing close to the conductor surface
DPEN
JREAL JEQUIVALENT
DW
Current lines
DPEN = skin depth
Current effective area
Less Proximity Effect influence
• The current in a close path distributes itself
in such a way so as to minimize the energy
drawn from the source.
Opposite current direction Same current direction
Current effective area
Current effective area
Leakage inductance less then 0.3%
The same Leakage inductance on different production lots
Conventional transformer
Pri
Sec
Sec
Planar Transformer
Combined Pri
and Sec
Better Leakage inductance
Combined Pri and Sec
0.9%
Magneto-motive Force in the Core Window
m.m.f.
(dc)
0
NIdH.f.m.m
m
Magneto-motive Force in the Core Window
Secondary
winding Primary
winding
Isolation gap
m.m.f.
(dc)
0
LF Current
Distribution in Windings
Multiple winding transformer
with interleaved
primary/secondary windings
Pa Pb Sb Sa
F=NI
Energy
density
[J/m] W [J]
Reduced leakage
inductance
* Interleaving: wide single layer winding folded accordion-wise to fit
available core winding breadth
* Drawing shows windings folded into 6 winding sections
* Each layer is a single turn stamped copper foil
* Same as having 6 times the core winding breadth
* Field is zero at each section boundary
* Each layer can be thicker than skin depth,
reduces DCR, aids heat removal
Interleaving the Windings
Top
Advantages
Large magnetic cross-section
Short winding length
Little winding extending outside core
* Reduced EMI
Disadvantages
Smaller winding breadth
Bottom
Advantages
Greater winding breadth
Manufacturability – cost
Large magnetic cross-section
Disadvantages
Longer winding length
Winding extends beyond core
* EMI
Core Shapes Planar
Core material (Ferrite) Conventional
1.Small winding area
2.Small number of turns (less then 20)
3.Force designing under high Frequency
Planar
Turns ratio
Bigger Surface for heat sink attaching
or cooling area
The two option benefits
1. Smaller dimensions With the same Power
2. Same dimensions With twice the Power
Efficiency = 100%- ΔP/P% ΔP - total losses P- Output Power
Example @ Total Losses are the same
Transformer 1
•Efficiency= 96%
•Losses= 4%
•Output Power=500W
Transformer 2
•Efficiency= 98%
•Losses= 2%
•Output Power=1000W
Example @ Total Losses are half
Transformer 1
•Efficiency= 96%
•Losses= 4%
•Output Power=500W
Transformer 2
•Efficiency= 98%
•Losses= 2%
•Output Power=500W
Main points for design request
• Total output Power
• Input / output voltages
• Working frequency
• Dielectric strength
• Special safety requirements (optional)
• Cooling conditions
• Mechanical dimensions requirements
• Qty & price
Planar Conventional
Payton can offer both solutions