DER-37
16W Adapter using TOP245P
April 27, 2004
7.5 Transformer Construction
Pull Pin 6&7 on bobbin [2] to provide polarization. Position bobbin in the
winding machine such that pins 1-4 are on the right side
Start at Pin 2. Wind 10 turns of 36 AWG wire in 1 layer. Spread turns
evenly across the bobbin. Finish on Pin1.
Bobbin Preparation
WDG1: Vbias
Basic Insulation
WDG2: Primary
1st layer
Use one layer of 13.7mm tape for basic insulation.
Start at Pin 3. Wind 46 turns of 31 AWG wire in 1 layer. Avoid
overlapping turns.
Basic Insulation
WDG2: Primary
2nd layer
Use one layer of 13.7mm tape for basic insulation.
Continue winding 13 turns of 31 AWG wire in the second layer. Do not
spread the turns. Finish on Pin 4
Basic Insulation
Use one layer of 13.7mm tape for basic insulation.
Use prepared copper shield shown in Figure 6. Start at Pin 4, wind 2 ½
turns in reverse direction.
Use one layer of 13.7mm tape for basic insulation.
Start at pin 8 temporarily. Starting from the topside of the bobbin wind 5
turns of quadfilar 26 AWG TIW. Finish on pin 5 temporarily.
Use two layers of 13.7mm tape for basic insulation.
Pull out pins 8 and 5, and let the secondary leads to float, mark the start
lead.
WDG3: SHLD
Basic Insulation
WDG4: SEC
Basic Insulation
Core Assembly
Core Wrap
Varnish
Insert gapped cores into the bobbin and glue them together
Wrap the secondary side of the core with two layers of 16.5mm tape as
shown in Figure 7 and Figure 8
Dip varnish the finished transformer
Figure 7 – Core 1st wrapping
Figure 8 – Core 2nd wrapping
Power Integrations
Tel: +1 408 414 9200 Fax: +1 408 414 9201
www.powerint.com
Page 14 of 32
POWERINT [ Power Integrations ]
