EPR-34 Datasheet, PDF (12/28 Pages) Power Integrations, Inc. – Engineering Prototype Report for EP 34 - Single Output 30 W AC-DC Power Supply

EPR-34 – 12 V, 30 W, Universal Input
7.4 Transformer Build Diagram
Pins Side
Margin
10-Feb-2004
Secondary
Bias
Primary
Figure 5 – EP-34 Transformer Build Diagram.
7.5 Transformer Construction
Bobbin Preparation
Primary Margin
Primary
Basic Insulation
Bifilar Bias Winding
Basic Insulation
12 V Quadrifilar
Secondary Winding
Outer Wrap
Core Preparation
Final Assembly
Pull Pin 8 on bobbin [2] to provide polarization. Bobbin pinout is shown
below.
Apply 1.5 mm wide margin to pin side of bobbin using item [5]. Match
height of primary and bias windings. Margin tape is needed to meet safety
spacing from primary winding to core and core to secondary pins.
Start at Pin 3. Wind 30 turns of item [3] in approximately 1 layer. Bring
finish lead back to start. Wind remaining 28 primary turns, finish on Pin 1.
Note: This “Z” winding technique significantly lowers primary capacitance
to reduce no-load power consumption.
Use two layers of item [6] for basic insulation.
Starting at Pin 5, wind 5 bifilar turns of item [3]. Spread turns evenly
across bobbin. Finish at Pin 4.
Use one layer of item [7] for basic insulation.
Start at Pins 9 and 10. Wind 6 quadrifilar turns of item [4] (about 1.2
layers). Spread turns evenly across bobbin. Finish on Pins 6 and 7.
Wrap windings with 3 layers of tape [item [7].
Wrap bottom of one E core [1] with 2 layers of tape [7] as shown.
Assemble and secure core halves so that the tape wrapped E core is at
the bottom of the transformer. Varnish impregnate (item [8]).
7.6 Transformer Sources
For information on the vendors used to source the transformers used on this board,
please visit the Power Integrations' Web site at the URL below and select “Engineering
Prototype Boards”.
http://www.powerint.com/componentsuppliers.htm
Power Integrations
Tel: [phone] Fax: [phone]
www.powerint.com
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