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DI-35

B

7/04

Power Integrations

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Power Integrations may make changes to its products at any time. Power Integrations has no liability arising from your use of any information, device or circuit

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SPECIFICALLY DISCLAIMS ALL WARRANTIES INCLUDING, WITHOUT LIMITATIONS, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A

PARTICULAR PURPOSE, AND NON-INFRINGEMENT OF THIRD PARTY RIGHTS. The products and applications illustrated herein (including circuits external to the

products and transformer construction) may be covered by one or more U.S. and foreign patents or potentially by pending U.S. and foreign patent applications

assigned to Power Integrations. A complete list of Power Integrations' patents may be found at

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Table 1. Transformer Construction Information.

Figure 3. Load Current for Thermal Test (10 ms/div).

Figure 2. 115 VAC V-I Curve.

TRANSFORMER PARAMETERS

Core Material

Nippon Ceramic EF-25-NC-2H

A

2

Bobbin

Miles-Platts FE0100 with

TBS-601 terminals

Winding Details

Primary: 65T, 2 layers, 28 AWG

Secondary: 9T, 2 x 26 AWG,

triple insulated

Bias: 7T, 2 x 28 AWG

Winding Order

(pin numbers)

Primary: 3-1, tape

Secondary: 9, 10-6,7, tape,

Bias: 4-5, tape 3L

Primary

Inductance

1059

µH ±10%

Primary Resonant

Frequency

0.75 MHz (min)

Leakage

Inductance

28

µH (max)

Table 2. Thermal Test with Pulsed Load of Figure 3. 25

°C

Ambient, Open Frame, 85 VAC and 265 VAC Input.

THERMAL TEST RESULTS

Thermal test load current is 1 A for 30 ms, 2.2 A for 10 ms

Test Case

T (

°C) at

85 VAC

T (

°C) at

265 VAC

T1 (Transformer)

57

59

U1 (TOP245P)

64

51

D7 (Op Rectifier)

58

59

C8 (Op Capacitor)

41

40

0

50

100

1

4

3

5

2

Time (ms)

6

7

0

-1

2.2 A

1 A

0

1

1.5

0.5

2

2.5

15.5

15.6

15.1

15.2

15.3

15.4

15

15.9

16

15.7

15.8

16.1

• Keep power loop layouts (primary and secondary) tight to

minimize noise (EMI and output ripple) and power loss.

heatsinking.

• 10,000 µF output buffer capacitor, standard ESR,

improves multi-channel audio transient capability.