07-May-2004
EPR-54 – LinkSwitch 2.75 W Low Cost Charger / Adapter
7.5 Transformer Construction
Pull Pin 8-10 on bobbin [2] to provide polarization.
Set bobbin with pins 1-5 on right hand side.
Start at Pin 1. Wind 33 turns of item [3] from right to left in 1 layer across
the entire width of the bobbin.
Bobbin Preparation
Shield Winding #1
Temporarily terminate wire on left hand side of bobbin.
Apply 1 layer of tape item [7].
Basic Insulation
Terminate
Terminate item [3] on pin 3.
Shield Winding #1 Cut pin 3 below termination to prevent contact with pcb trace.
Basic Insulation
(continued)
Apply an additional 3 layers of tape item [7].
Start at pin 2. Wind 100 turns of item [3] in 3 layers, plus 3 to 5 additional
turns. Wind uniformly across the entire width of the bobbin with no empty
space or gaps in any layer. Finish at pin 1.
Primary
Winding #2
Assemble and apply foil shield [4] starting 3 mm from bottom side of
bobbin [2]; such that foil termination wire aligns with pin 4. Insert the foil
shield assembly [4] beneath a 10-15 mm long piece of tape (to hold in
place).
Foil Shield
Wrap beneath 1 layer item [7] and terminate foil at pin 4.
Apply 4 layers of item [11] on both sides of the bobbin ensuring no space
to either bobbin wall.
Margin Tape
Change the bobbin [2] orientation with pins 6-10 on right hand side.
Maintain same spindle rotation direction.
Bobbin Preparation
Temporarily start at pin 1. Wind 8 turns item [5] in 1 layer from left to
right. Wind uniformly across the entire width of the bobbin with no empty
space or gaps in the layer. Finish at pin 7.
Secondary
Winding #3
Remove start from pin 1 and reattach to pin 6.
Basic Insulation
Apply 2 layers tape item [7].
Apply 4 layers of item [11] on left side of the bobbin ensuring no space to
bobbin wall.
Margin Tape
L and R
Apply 4 layers of item [12] on right side of the bobbin ensuring no space
to bobbin wall.
Start at pin 4. Wind 14 turns item [6] from left to right. Wind uniformly
across the entire width of the bobbin with no empty space or gaps in the
layer.
Bias
Winding #4
Apply 1 layer of tape item [6], maintaining bias winding exit at edge of
margin tape barrier.
Basic Insulation
Bias
Continue winding item [6] from right to left. Wind a total of 26 turns
item [6]. Finish on pin 5.
Winding #4
(continued)
Outer
Apply 2 layers of tape item [7].
Insulation
Assemble and secure core halves with item [12].
Dip varnish and cure (do not vacuum impregnate).
Final Assembly
Power Integrations
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