49 PC500.C (3/03)
US 858 674 8100
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UK 44 1483 401 700
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France 33 3 84 35 04 04
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Singapore 65 6287 8998
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Taiwan 886 2 2698 0228
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Hong Kong 852 2788 6588
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http://www.pulseeng.com
HIGH FREQUENCY PLANAR
TRANSFORMERS
Spyglass Series (up to 140W)
1. This series of transformers was designed for (but not limited to)
single and two switch forward converter applications. The
power levels stated are for actual demo boards typically operat-
ing between 200-400kHz with 100-200LFM of airflow. Other
turns ratios and auxiliary windings may be available. Please
contact Pulse Power Applications Engineering for details.
2. The leakage inductance is measured at the primary terminals
with all other windings shorted.
3. The listed transformers are designed to meet basic insulation
(1.4mm creepage and clearance with 1500Vdc isolation). Lower
cost transformers with operational insulation (1500Vdc isolation
with no creepage and clearance spacings) are available. Please
contact Pulse Power Applications Engineering for details.
4. To determine if the transformer is suitable for your application,
it is necessary to ensure that the temperature rise of the
component (ambieint plus temperature rise) does not exceed
its operating temperature. To determine the temperature rise
of the component it is necessary to calculate the total power
losses (core and copper) in the application.
Total Copper Losses (Pcu total(W)):
Pcu total(W) = sum of the losses in each winding
The losses in each winding can be calculated by:
Pcu(W) = .001* DCR(mΩ) * (Irms2)
Core Losses (Pcore(W))
To calculate core loss, use the following formula:
CoreLoss (W) = 1.589E-13 (∆B)2.5 * (Freq kHz)1.8
where:
∆B = 179211.46 * Vin min * Dutycycle max / (Freq kHz *
Primary Turns)
Total Losses:
P total = Pcu total + CoreLoss
Temperature Rise:
The approximate temperature rise can be found by looking
up the calculated total losses in the temperature rise vs.
power dissipation curve.
Notes from Tables