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Prototype Specifics
Determine how many Primary Boards and Secondary Stamps are needed to
satisfy the number of turns in the design.
The number of turns for the primary winding can be determined by using the
following equation:
where:
N = number of turns
V = Voltage
t = time = (1 ÷ frequency) × duty cycle
A
= core area = 0.473 cm
e
B = flux density (Gauss)
The amount of current the prototype can handle depends on the number of
stamps used in the secondary. Each stamp is the equivalent of 16.5 AWG.
Refer to the diagrams of the Primary Boards and Stamps and take note of the
typical DCR rating of each. If the DCR requirement is met, the prototype can be
built. If the DCR of the primary is higher than desired, double the number of
Primary Boards and connect them in parallel. If the DCR of the secondary is
higher than desired, double the number of stamps. Keep in mind the maximum
number of parts that can fit in the core.
Primary turns
Secondary turns
Auxiliary turns
Current handling
Assembling the Prototype
Select all the parts needed to build the prototype, including an insulator washer
to be used between each part of the prototype. The following points should be
taken into account in order to assemble a prototype that will closely match the
final production planar component.
•
To minimize leakage inductance, make sure that the boards, stamps and
insulators are sandwiched tightly together. The tighter all the parts are to
each other, the lower the leakage inductance.
Planar Transformer Prototyping Kit
N = V × t × 10
2
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A
× B
e
Required DCR
Required DCR
Document 355 Revised 08/26/08
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